Researchers have uncovered the complete genetic make-up of the cavity-causing bacterium Bifidobacterium dentium Bd1, revealing the genetic adaptations that allow this microorganism to live and cause decay in the human oral cavity. The study, led by Marco Ventura's Probiogenomics laboratory at the University of Parma, and Prof. Douwe van Sinderen and Dr Paul O'Toole of the Alimentary Pharmabiotic Centre at University College Cork, is published December 24 in the open-access journal PLoS Genetics.
Bifidobacteria, largely known as long-term beneficial gut bacteria, are often included as probiotic components of food to aid digestion and boost the immune system. However, not all species within the genus Bifidobacterium provide beneficial effects to the host's health. In fact, the Bifidobacterium dentium species is an opportunistic pathogen since it has been linked to the development of tooth decay. The genome sequence of B. dentium Bd1 reveals how this microorganism has adapted to the oral environment through specialized nutrient acquisition features, acid tolerance, defences against antimicrobial substances and other gene products that increase fitness and competitiveness within the oral niche.
This report identifies, through various genomic approaches, specific adaptations of a Bifidobacterium taxon to a lifestyle as a tooth decay-causing bacterium. The data in this study indicate that the genome of this opportunistic pathogen has evolved through only a small number of horizontal gene acquisition events, highlighting the narrow boundary that separates bacteria that are long-term residents on or in the human body from opportunistic pathogens.
Saturday, December 26, 2009
Thursday, December 24, 2009
Cracking The Root Of Tooth Strength
After years of biting and chewing, how are human teeth able to remain intact and functional? A team of researchers from The George Washington University and other international scholars have discovered several features in enamel—the outermost tooth tissue—that contribute to the resiliency of human teeth.
A human molar compared to a sea otter molar. (Credit: The George Washington University)
Human enamel is brittle. Like glass, it cracks easily; but unlike glass, enamel is able to contain cracks and remain intact for most individuals’ lifetimes. The research team discovered that the major reason why teeth do not break apart is due to the presence of tufts—small, crack-like defects found deep in the enamel. Tufts arise during tooth development, and all human teeth contain multiple tufts before the tooth has even erupted into the mouth.
Many cracks in teeth do not start at the outer surface of the tooth, as has always been assumed. Instead cracks arise from tufts located deep inside the enamel. From here, cracks can grow towards the outer tooth surface. Once reaching the surface, these cracks can potentially act as sites for dental decay. Acting together like a forest of small flaws, tufts suppress the growth of these cracks by distributing the stress amongst themselves.
“This is the first time that enigmatic developmental features, such as enamel tufts, have been shown to have any significance in tooth function” said GW researcher Paul Constantino. “Crack growth is also hampered by the “basket weave” microstructure of enamel, and by a ‘self-healing’ process whereby organic material fills cracks extended from the tufts, which themselves also become closed by organic matter. This type of infilling bonds the opposing crack walls, which increases the amount of force required to extend the crack later on.”
This research evolved as part of an interdisciplinary collaboration between anthropologists from The George Washington University and physical scientists from the National Institute of Standards and Technology in Gaithersburg, Md. The team studied tooth enamel in humans and also sea otters, mammals with teeth showing remarkable resemblances to those of humans.
A human molar compared to a sea otter molar. (Credit: The George Washington University)
Human enamel is brittle. Like glass, it cracks easily; but unlike glass, enamel is able to contain cracks and remain intact for most individuals’ lifetimes. The research team discovered that the major reason why teeth do not break apart is due to the presence of tufts—small, crack-like defects found deep in the enamel. Tufts arise during tooth development, and all human teeth contain multiple tufts before the tooth has even erupted into the mouth.
Many cracks in teeth do not start at the outer surface of the tooth, as has always been assumed. Instead cracks arise from tufts located deep inside the enamel. From here, cracks can grow towards the outer tooth surface. Once reaching the surface, these cracks can potentially act as sites for dental decay. Acting together like a forest of small flaws, tufts suppress the growth of these cracks by distributing the stress amongst themselves.
“This is the first time that enigmatic developmental features, such as enamel tufts, have been shown to have any significance in tooth function” said GW researcher Paul Constantino. “Crack growth is also hampered by the “basket weave” microstructure of enamel, and by a ‘self-healing’ process whereby organic material fills cracks extended from the tufts, which themselves also become closed by organic matter. This type of infilling bonds the opposing crack walls, which increases the amount of force required to extend the crack later on.”
This research evolved as part of an interdisciplinary collaboration between anthropologists from The George Washington University and physical scientists from the National Institute of Standards and Technology in Gaithersburg, Md. The team studied tooth enamel in humans and also sea otters, mammals with teeth showing remarkable resemblances to those of humans.
Proline Repeats Help Protein Grow Tooth Enamel
A simple amino acid that is repeated in the center of proteins found in tooth enamel makes teeth stronger and more resilient, according to new research at the University of Illinois at Chicago.
Researchers compared proline repeats in amphibian and animal models and discovered that when the repeats are short, such as in frogs, teeth will not have the enamel prisms that are responsible for the strength of human enamel. In contrast, when the proline repeats are long, they contract groups of molecules that help enamel crystals grow.
The findings will be published in the December 21 online version of the Journal PLoS Biology.
"Proline repeats are amazing," said Tom Diekwisch, professor and head of oral biology in the UIC College of Dentistry and lead researcher on the study. "They hold the key to understanding the structure and function of many natural proteins, including mucins, antifreeze proteins, Alzheimer amyloid, and prion proteins.
"We hope that our findings will help many other important areas of scientific research, including the treatment of neurodegenerative diseases."
When tooth enamel is grown it is bathed in bubble-shaped groupings of proteins, Diekwisch said. The size of the protein bubbles varies in different animals, from 5 nanometers in cows to 20 nanometers in mice and 40 nanometers in frogs.
Diekwisch's team discovered that the longer the stretch of proline repeats, the more the protein bubbles contracted. The study also showed that the smaller protein bubbles were associated with longer enamel crystals, he said.
The new discovery, Diekwisch said, will give new clues to engineer tooth enamel.
"We hope that one day these findings will help people replace lost parts of the tooth with a healthy layer of new enamel."
Researchers compared proline repeats in amphibian and animal models and discovered that when the repeats are short, such as in frogs, teeth will not have the enamel prisms that are responsible for the strength of human enamel. In contrast, when the proline repeats are long, they contract groups of molecules that help enamel crystals grow.
The findings will be published in the December 21 online version of the Journal PLoS Biology.
"Proline repeats are amazing," said Tom Diekwisch, professor and head of oral biology in the UIC College of Dentistry and lead researcher on the study. "They hold the key to understanding the structure and function of many natural proteins, including mucins, antifreeze proteins, Alzheimer amyloid, and prion proteins.
"We hope that our findings will help many other important areas of scientific research, including the treatment of neurodegenerative diseases."
When tooth enamel is grown it is bathed in bubble-shaped groupings of proteins, Diekwisch said. The size of the protein bubbles varies in different animals, from 5 nanometers in cows to 20 nanometers in mice and 40 nanometers in frogs.
Diekwisch's team discovered that the longer the stretch of proline repeats, the more the protein bubbles contracted. The study also showed that the smaller protein bubbles were associated with longer enamel crystals, he said.
The new discovery, Diekwisch said, will give new clues to engineer tooth enamel.
"We hope that one day these findings will help people replace lost parts of the tooth with a healthy layer of new enamel."
Monday, December 21, 2009
Adding raisin to cereals = no extra plaque
Elevated dental plaque acid is a risk factor that contributes to cavities in children. But eating bran flakes with raisins containing no added sugar does not promote more acid in dental plaque than bran flakes alone, according to new research at the University of Illinois at Chicago.
Some dentists believe sweet, sticky foods such as raisins cause cavities because they are difficult to clear off the tooth surfaces, said Christine Wu, professor and director of cariology research at UIC and lead investigator of the study.
But studies have shown that raisins are rapidly cleared from the surface of the teeth just like apples, bananas and chocolate, she said.
In the study, published in the journal Pediatric Dentistry, children ages 7 to 11 compared four food groups -- raisins, bran flakes, commercially marketed raisin bran cereal, and a mix of bran flakes with raisins lacking any added sugar.
Sucrose, or table sugar, and sorbitol, a sugar substitute often used in diet foods, were also tested as controls.
Children chewed and swallowed the test foods within two minutes. The acid produced by the plaque bacteria on the surface of their teeth was measured at intervals.
All test foods except the sorbitol solution promoted acid production in dental plaque over 30 minutes, with the largest production between 10 to 15 minutes.
Wu says there is a "well-documented" danger zone of dental plaque acidity that puts a tooth's enamel at risk for mineral loss that may lead to cavities. Achint Utreja, a research scientist and dentist formerly on Wu's team, said plaque acidity did not reach that point after children consumed 10 grams of raisins. Adding unsweetened raisins to bran flakes did not increase plaque acid compared to bran flakes alone.
However, eating commercially marketed raisin bran led to significantly more acid in the plaque, he said, reaching into what Wu identified as the danger zone.
Plaque bacteria on tooth surfaces can ferment various sugars such as glucose, fructose or sucrose and produce acids that may promote decay. But sucrose is also used by bacteria to produce sticky sugar polymers that help the bacteria remain on tooth surfaces, Wu said. Raisins themselves do not contain sucrose.
In a previous study at UIC, researchers identified several natural compounds from raisins that can inhibit the growth of some oral bacteria linked to cavities or gum disease.
Some dentists believe sweet, sticky foods such as raisins cause cavities because they are difficult to clear off the tooth surfaces, said Christine Wu, professor and director of cariology research at UIC and lead investigator of the study.
But studies have shown that raisins are rapidly cleared from the surface of the teeth just like apples, bananas and chocolate, she said.
In the study, published in the journal Pediatric Dentistry, children ages 7 to 11 compared four food groups -- raisins, bran flakes, commercially marketed raisin bran cereal, and a mix of bran flakes with raisins lacking any added sugar.
Sucrose, or table sugar, and sorbitol, a sugar substitute often used in diet foods, were also tested as controls.
Children chewed and swallowed the test foods within two minutes. The acid produced by the plaque bacteria on the surface of their teeth was measured at intervals.
All test foods except the sorbitol solution promoted acid production in dental plaque over 30 minutes, with the largest production between 10 to 15 minutes.
Wu says there is a "well-documented" danger zone of dental plaque acidity that puts a tooth's enamel at risk for mineral loss that may lead to cavities. Achint Utreja, a research scientist and dentist formerly on Wu's team, said plaque acidity did not reach that point after children consumed 10 grams of raisins. Adding unsweetened raisins to bran flakes did not increase plaque acid compared to bran flakes alone.
However, eating commercially marketed raisin bran led to significantly more acid in the plaque, he said, reaching into what Wu identified as the danger zone.
Plaque bacteria on tooth surfaces can ferment various sugars such as glucose, fructose or sucrose and produce acids that may promote decay. But sucrose is also used by bacteria to produce sticky sugar polymers that help the bacteria remain on tooth surfaces, Wu said. Raisins themselves do not contain sucrose.
In a previous study at UIC, researchers identified several natural compounds from raisins that can inhibit the growth of some oral bacteria linked to cavities or gum disease.
Monday, December 14, 2009
90% with Gum Disease Are at Risk for Diabetes
Study Finds Over 90% of People with Gum Disease Are at Risk for Diabetes; Concludes That at Least Half Could Be Screened in Dental Offices
An overwhelming majority of people who have periodontal (gum) disease are also at high risk for diabetes and should be screened for diabetes, a New York University nursing-dental research team has found. The researchers also determined that half of those at risk had seen a dentist in the previous year, concluded that dentists should consider offering diabetes screenings in their offices, and described practical approaches to conducting diabetes screenings in dental offices.
The study, led by Dr. Shiela Strauss, Associate Professor of Nursing and Co-Director of the Statistics and Data Management Core for NYU’s Colleges of Dentistry and Nursing, examined data from 2,923 adult participants in the 2003-2004 National Health and Nutrition Examination Survey who had not been diagnosed with diabetes. The survey, conducted by the National Center for Health Statistics of the Centers for Disease Control and Prevention, was designed to assess the health and nutritional status of adults and children in the United States.
Using guidelines established by the American Diabetes Association, Dr. Strauss determined that 93 percent of subjects who had periodontal disease, compared to 63 percent of those without the disease, were considered to be at high risk for diabetes and should be screened for diabetes. The guidelines recommend diabetes screening for people at least 45 years of age with a body mass index (a comparative measure of weight and height) of 25 or more, as well as for those under 45 years of age with a BMI of 25 or more who also have at least one additional diabetes risk factor. In Dr. Strauss’s study, two of those additional risk factors - high blood pressure and a first-degree relative (a parent or sibling) with diabetes - were reported in a significantly greater number of subjects with periodontal disease than in subjects without the disease. Dr. Strauss’s findings, published today in the online edition of the Journal of Public Health Dentistry, add to a growing body of evidence linking periodontal infections to an increased risk for diabetes.
Dr. Strauss also examined how often those with gum disease and a risk for diabetes visit a dentist, finding that three in five reported a dental visit in the past two years; half in the past year; and a third in the past six months.
“In light of these findings, the dental visit could be a useful opportunity to conduct an initial diabetes screening — an important first step in identifying those patients who need follow-up testing to diagnose the disease.”
“It’s been estimated that 5.7 million Americans with diabetes were undiagnosed in 2007,” Dr. Strauss added, “with the number expected to increase dramatically in coming years. The issue of undiagnosed diabetes is especially critical because early treatment and secondary prevention efforts may help to prevent or delay the long-term complications of diabetes that are responsible for reduced quality of life and increased levels of mortality among these patients. Thus, there is a critical need to increase opportunities for diabetes screening and early diabetes detection.”
Dr. Strauss said that dentists could screen patients for diabetes by evaluating them for risk factors such as being overweight; belonging to a high-risk ethnic group (African-American, Latino, Native American, Asian-American, or Pacific Islander); having high cholesterol; high blood pressure; a first-degree relative with diabetes; or gestational diabetes mellitus; or having given birth to a baby weighing more than nine pounds.
Alternatively, dentists could use a glucometer — a diagnostic instrument for measuring blood glucose — to analyze finger-stick blood samples, or use the glucometer to evaluate blood samples taken from pockets of inflammation in the gums.
“The oral blood sample would arguably be more acceptable to dentists because providers and patients anticipate oral intervention in the dental office,” Dr. Strauss noted. In an earlier study involving 46 subjects with periodontal disease published in June 2009 by the Journal of Periodontology, an NYU nursing-dental research team led by Dr. Strauss determined that the glucometer can provide reliable glucose-level readings for blood samples drawn from deep pockets of gum inflammation, and that those readings were highly correlated with glucometer readings for finger-stick blood samples.
An overwhelming majority of people who have periodontal (gum) disease are also at high risk for diabetes and should be screened for diabetes, a New York University nursing-dental research team has found. The researchers also determined that half of those at risk had seen a dentist in the previous year, concluded that dentists should consider offering diabetes screenings in their offices, and described practical approaches to conducting diabetes screenings in dental offices.
The study, led by Dr. Shiela Strauss, Associate Professor of Nursing and Co-Director of the Statistics and Data Management Core for NYU’s Colleges of Dentistry and Nursing, examined data from 2,923 adult participants in the 2003-2004 National Health and Nutrition Examination Survey who had not been diagnosed with diabetes. The survey, conducted by the National Center for Health Statistics of the Centers for Disease Control and Prevention, was designed to assess the health and nutritional status of adults and children in the United States.
Using guidelines established by the American Diabetes Association, Dr. Strauss determined that 93 percent of subjects who had periodontal disease, compared to 63 percent of those without the disease, were considered to be at high risk for diabetes and should be screened for diabetes. The guidelines recommend diabetes screening for people at least 45 years of age with a body mass index (a comparative measure of weight and height) of 25 or more, as well as for those under 45 years of age with a BMI of 25 or more who also have at least one additional diabetes risk factor. In Dr. Strauss’s study, two of those additional risk factors - high blood pressure and a first-degree relative (a parent or sibling) with diabetes - were reported in a significantly greater number of subjects with periodontal disease than in subjects without the disease. Dr. Strauss’s findings, published today in the online edition of the Journal of Public Health Dentistry, add to a growing body of evidence linking periodontal infections to an increased risk for diabetes.
Dr. Strauss also examined how often those with gum disease and a risk for diabetes visit a dentist, finding that three in five reported a dental visit in the past two years; half in the past year; and a third in the past six months.
“In light of these findings, the dental visit could be a useful opportunity to conduct an initial diabetes screening — an important first step in identifying those patients who need follow-up testing to diagnose the disease.”
“It’s been estimated that 5.7 million Americans with diabetes were undiagnosed in 2007,” Dr. Strauss added, “with the number expected to increase dramatically in coming years. The issue of undiagnosed diabetes is especially critical because early treatment and secondary prevention efforts may help to prevent or delay the long-term complications of diabetes that are responsible for reduced quality of life and increased levels of mortality among these patients. Thus, there is a critical need to increase opportunities for diabetes screening and early diabetes detection.”
Dr. Strauss said that dentists could screen patients for diabetes by evaluating them for risk factors such as being overweight; belonging to a high-risk ethnic group (African-American, Latino, Native American, Asian-American, or Pacific Islander); having high cholesterol; high blood pressure; a first-degree relative with diabetes; or gestational diabetes mellitus; or having given birth to a baby weighing more than nine pounds.
Alternatively, dentists could use a glucometer — a diagnostic instrument for measuring blood glucose — to analyze finger-stick blood samples, or use the glucometer to evaluate blood samples taken from pockets of inflammation in the gums.
“The oral blood sample would arguably be more acceptable to dentists because providers and patients anticipate oral intervention in the dental office,” Dr. Strauss noted. In an earlier study involving 46 subjects with periodontal disease published in June 2009 by the Journal of Periodontology, an NYU nursing-dental research team led by Dr. Strauss determined that the glucometer can provide reliable glucose-level readings for blood samples drawn from deep pockets of gum inflammation, and that those readings were highly correlated with glucometer readings for finger-stick blood samples.
Wednesday, December 9, 2009
Older mercury-based fillings unlikely to be toxic
A new study, "The Chemical Forms of Mercury in Aged and Fresh Dental Amalgam Surfaces," on the surface chemistry of silver-colored, mercury-based dental fillings suggests that the surface forms of mercury may be less toxic than previously thought. It appears online in ACS' journal Chemical Research in Toxicology.
In the study, Graham George and colleagues note that mercury-based fillings, also called amalgams, have been used by dentists to repair teeth for well-over a century. In recent decades their use has become controversial because of concerns about exposure to potentially toxic mercury. However, mercury can potentially exist in several different chemical forms, each with a different toxicity. Prior to this report, little was known about how the chemical forms of mercury in dental amalgam might change over time.
Using a special X-ray technique, the scientists analyzed the surface of freshly prepared metal fillings and compared these with the surface of aged fillings (about 20 years old) from a dental clinic. Fresh fillings contained metallic mercury, which can be toxic. Aged fillings, however, typically contain a form of mercury, called beta-mercuric sulfide or metacinnabar, which is unlikely to be toxic in the body. The scientists found that the surfaces of metal fillings seem to lose up to 95 percent of their mercury over time. Loss of potentially toxic mercury from amalgam may be due to evaporation, exposure to some kinds of dental hygiene products, exposure to certain foods, or other factors. The scientists caution that "human exposure to mercury lost from fillings is still of concern."
In the study, Graham George and colleagues note that mercury-based fillings, also called amalgams, have been used by dentists to repair teeth for well-over a century. In recent decades their use has become controversial because of concerns about exposure to potentially toxic mercury. However, mercury can potentially exist in several different chemical forms, each with a different toxicity. Prior to this report, little was known about how the chemical forms of mercury in dental amalgam might change over time.
Using a special X-ray technique, the scientists analyzed the surface of freshly prepared metal fillings and compared these with the surface of aged fillings (about 20 years old) from a dental clinic. Fresh fillings contained metallic mercury, which can be toxic. Aged fillings, however, typically contain a form of mercury, called beta-mercuric sulfide or metacinnabar, which is unlikely to be toxic in the body. The scientists found that the surfaces of metal fillings seem to lose up to 95 percent of their mercury over time. Loss of potentially toxic mercury from amalgam may be due to evaporation, exposure to some kinds of dental hygiene products, exposure to certain foods, or other factors. The scientists caution that "human exposure to mercury lost from fillings is still of concern."
Tuesday, December 8, 2009
The state of pediatric oral health in US
Special issue of Academic Pediatrics reports on state of pediatric oral health in US
Oral disease, primarily dental caries, is the most common pediatric disease and can lead to physical and psychological disabilities as well as significant morbidity in adulthood. In May 2000, Dr David Satcher's landmark report, Oral Health in America: A Report of the Surgeon General, highlighted the state of oral health for children and adults in the United States and offered strategies to improve oral health outcomes. The November/December issue of Academic Pediatrics, devoted entirely to children's oral health, represents a ''midterm examination'' of how far the US has come since the 2000 Surgeon General's report in meeting Healthy People 2010 oral health objectives and other key recommendations.
Bringing together 19 contributions from experts in dentistry, medicine, nursing, and public policy, guest editors Wendy E. Mouradian and Rebecca L. Slayton have assembled an impressive summary of the state of children's oral health in the US and urge healthcare professionals to make oral health a pediatric priority. A number of papers were presented at the landmark American Academy of Pediatrics' (AAP) National Summit on Children's Oral Health: A New Era of Collaboration, held November 7-8, 2008 in Chicago.
In his commentary, Editor-in-Chief Peter G. Szilagyi, University of Rochester Medical Center, asks the question, "Why should Academic Pediatrics devote an entire issue to children's oral health now?" His answers: "First, oral health is health, and children's oral health is part of pediatrics...Second, we are far from achieving our Healthy People 2010 oral health objectives in reducing the prevalence of caries in children...Third, substantial disparities exist in children's oral health and access to care...Fourth, oral health represents an excellent paradigm in which the traditional pediatric community needs to work more closely with other health professionals—in this case dental professionals—to advance the health of children."
Szilagyi continues, "I look forward to the day when a future issue of Academic Pediatrics or a future Surgeon General's report proclaims victory on the plight of dental caries and declares that children's mouths are largely absent of dental or oral disease."
Wendy E. Mouradian and her co-authors then present an overview of the papers and comment on progress made in meeting Surgeon General David Satcher's goals set in 2000, calling for "dentists, physicians, and other health professionals who work with children to embrace a shared responsibility for children's oral health and work to overcome the historic separation between dentistry and medicine...." Dr. Satcher himself follows with a renewed call to arms to improve children's oral health.
Rebecca L. Slayton and Harold C. Slavkin address how scientific and technological advances in sequencing of the human genome, tissue engineering and saliva diagnostics may have significant potential to impact oral health.
Paul S. Casamassimo relates the medical history of a young man with special-needs, to illustrate how oral health may be mishandled by both community dentists and physicians in a health care system with too many gaps, in "A Life Without Teeth."
The Science and Surveillance section includes articles that discuss tooth decay, especially in younger children, and the lack of improvement in reducing this disease. Children's diets, a subject of recent concern for obesity, can also increase dental caries.
Three articles dealing with Access and Barriers to Care are included. These review current measures of access to dental care for children, including those with special health care needs, and the ethical and policy issues in the care of children with craniofacial conditions including quality of life, costs of care, and prenatal diagnosis of craniofacial defects,
The Oral Health Workforce, including dental and medical education issues, is covered in six articles. Authors review the state of the oral health workforce, including new models of mid-level dental practitioners, and stress the need to better educate both dentists (especially general and pediatric dentists) and primary care medical providers (pediatricians, family physicians, nurse practitioners, physicians' assistants) to promote children's oral health and ensure they have adequate access to dental care.
Finally, two articles on Policy Achievements and Challenges discuss how government actions and policy decisions have affected children's oral health. Burton Edelstein writes about congressional action to reauthorize CHIP (Child's Health Insurance Program) and to include funding for oral care. James J. Crall discusses how the Surgeon General's Report on Oral Health drove Congress and State Legislatures, Federal and State Agencies, the Federal Courts, and various professional societies and associations to adopt policies and procedures to enhance children's oral health, and reflects on the work remaining to fully address children's oral health needs.
Oral disease, primarily dental caries, is the most common pediatric disease and can lead to physical and psychological disabilities as well as significant morbidity in adulthood. In May 2000, Dr David Satcher's landmark report, Oral Health in America: A Report of the Surgeon General, highlighted the state of oral health for children and adults in the United States and offered strategies to improve oral health outcomes. The November/December issue of Academic Pediatrics, devoted entirely to children's oral health, represents a ''midterm examination'' of how far the US has come since the 2000 Surgeon General's report in meeting Healthy People 2010 oral health objectives and other key recommendations.
Bringing together 19 contributions from experts in dentistry, medicine, nursing, and public policy, guest editors Wendy E. Mouradian and Rebecca L. Slayton have assembled an impressive summary of the state of children's oral health in the US and urge healthcare professionals to make oral health a pediatric priority. A number of papers were presented at the landmark American Academy of Pediatrics' (AAP) National Summit on Children's Oral Health: A New Era of Collaboration, held November 7-8, 2008 in Chicago.
In his commentary, Editor-in-Chief Peter G. Szilagyi, University of Rochester Medical Center, asks the question, "Why should Academic Pediatrics devote an entire issue to children's oral health now?" His answers: "First, oral health is health, and children's oral health is part of pediatrics...Second, we are far from achieving our Healthy People 2010 oral health objectives in reducing the prevalence of caries in children...Third, substantial disparities exist in children's oral health and access to care...Fourth, oral health represents an excellent paradigm in which the traditional pediatric community needs to work more closely with other health professionals—in this case dental professionals—to advance the health of children."
Szilagyi continues, "I look forward to the day when a future issue of Academic Pediatrics or a future Surgeon General's report proclaims victory on the plight of dental caries and declares that children's mouths are largely absent of dental or oral disease."
Wendy E. Mouradian and her co-authors then present an overview of the papers and comment on progress made in meeting Surgeon General David Satcher's goals set in 2000, calling for "dentists, physicians, and other health professionals who work with children to embrace a shared responsibility for children's oral health and work to overcome the historic separation between dentistry and medicine...." Dr. Satcher himself follows with a renewed call to arms to improve children's oral health.
Rebecca L. Slayton and Harold C. Slavkin address how scientific and technological advances in sequencing of the human genome, tissue engineering and saliva diagnostics may have significant potential to impact oral health.
Paul S. Casamassimo relates the medical history of a young man with special-needs, to illustrate how oral health may be mishandled by both community dentists and physicians in a health care system with too many gaps, in "A Life Without Teeth."
The Science and Surveillance section includes articles that discuss tooth decay, especially in younger children, and the lack of improvement in reducing this disease. Children's diets, a subject of recent concern for obesity, can also increase dental caries.
Three articles dealing with Access and Barriers to Care are included. These review current measures of access to dental care for children, including those with special health care needs, and the ethical and policy issues in the care of children with craniofacial conditions including quality of life, costs of care, and prenatal diagnosis of craniofacial defects,
The Oral Health Workforce, including dental and medical education issues, is covered in six articles. Authors review the state of the oral health workforce, including new models of mid-level dental practitioners, and stress the need to better educate both dentists (especially general and pediatric dentists) and primary care medical providers (pediatricians, family physicians, nurse practitioners, physicians' assistants) to promote children's oral health and ensure they have adequate access to dental care.
Finally, two articles on Policy Achievements and Challenges discuss how government actions and policy decisions have affected children's oral health. Burton Edelstein writes about congressional action to reauthorize CHIP (Child's Health Insurance Program) and to include funding for oral care. James J. Crall discusses how the Surgeon General's Report on Oral Health drove Congress and State Legislatures, Federal and State Agencies, the Federal Courts, and various professional societies and associations to adopt policies and procedures to enhance children's oral health, and reflects on the work remaining to fully address children's oral health needs.
Monday, December 7, 2009
Nearly 1/3 of human genome is involved in gingivitis
Gingivitis, which may affect more than one-half of the U.S. adult population, is a condition commonly attributed to lapses in simple oral hygiene habits. However, a new study shows that development and reversal of gingivitis at the molecular level is apparently much more complicated than its causes might indicate.
Research conducted jointly by the University of North Carolina at Chapel Hill and Procter & Gamble (P&G) Oral Care has found that more than 9,000 genes – nearly 30 percent of the genes found in the human body – are expressed differently during the onset and healing process associated with gingivitis. Biological pathways associated with activation of the immune system were found to be the major pathways being activated and critical to controlling the body's reaction to plaque build-up on the teeth. Additionally, other gene expression pathways activated during plaque overgrowth include those involved in wound healing, neural processes and skin turnover.
Results of the study are published today in the December 2009 edition of the Journal of Periodontology. This study is the first to successfully identify gene expression and biological pathways involved with the onset and healing process of gingivitis.
Gingivitis is characterized by gums that are red, swollen and tender and that bleed easily during brushing and flossing. If untreated, gingivitis can lead to periodontal disease, which has been studied extensively for its possible relation to heart disease, diabetes and pre-term birth. Researchers said that understanding how gingivitis develops and resolves on a molecular level can possibly provide critical insights into gum disease prevention, as well as new treatments.
"The study's findings demonstrate that clinical symptoms of gingivitis reflect complicated changes in cellular and molecular processes within the body," said Steven Offenbacher, D.D.S., Ph.D., the study's lead author and director of the UNC School of Dentistry-based Center for Oral and Systemic Diseases. "Understanding the thousands of individual genes and multiple systems involved in gingivitis will help explain exactly what is occurring in a person's body at the onset of the disease and how it relates to their overall health."
The build-up of plaque formed during the onset of gingivitis represents the overgrowth of bacteria as a biofilm on the teeth above and below the gum line. Biofilms can form in other parts of the body and are known to be involved with health conditions, such as urinary tract infections, ear infections and chronic sinusitis. Researchers believe learning about how the body interacts with bacteria overgrowth during gingivitis could provide insight into a variety of bio-film-associated diseases.
"Data generated by the study will be crucial in developing new approaches to treating gingivitis," said Leslie Winston, D.D.S., Ph.D., co-author of the study and Director of Professional and Scientific Relations at P&G Oral Care (makers of Crest and Oral-B). "We plan to conduct additional research to identify biomarkers of gum disease in at risk individuals and hope that this will lead to new and more advanced treatment options and preventative measures."
About the Study
The objective of this study was to understand gingivitis on a molecular level by identifying changes in gene expression taking place in the mouth during gingivitis onset and the healing process. Fourteen healthy individuals with mild gingivitis participated in the study. After baseline tooth cleanings, gingivitis was induced in each study participant, followed by the participants adhering to an oral hygiene regimen of twice-daily brushing and regular flossing. Gum tissue was collected at baseline, four weeks after the induction of gingivitis and one week after resuming the oral hygiene regimen of brushing and flossing.
Gene expression data was analyzed using gene chip technology that enabled the investigators to detect changes in the expression of more than 30,000 genes. By applying advanced genomics bioinformatics tools, the investigators were able to identify the biological pathways and gene expression patterns associated with gingivitis.
As part of the study findings, researchers identified several biological pathways triggered by the onset and healing of gingivitis, including those associated with immune response, energy metabolism, neural processes, vasculature, chemotaxis, wound healing and steroid metabolism.
Research conducted jointly by the University of North Carolina at Chapel Hill and Procter & Gamble (P&G) Oral Care has found that more than 9,000 genes – nearly 30 percent of the genes found in the human body – are expressed differently during the onset and healing process associated with gingivitis. Biological pathways associated with activation of the immune system were found to be the major pathways being activated and critical to controlling the body's reaction to plaque build-up on the teeth. Additionally, other gene expression pathways activated during plaque overgrowth include those involved in wound healing, neural processes and skin turnover.
Results of the study are published today in the December 2009 edition of the Journal of Periodontology. This study is the first to successfully identify gene expression and biological pathways involved with the onset and healing process of gingivitis.
Gingivitis is characterized by gums that are red, swollen and tender and that bleed easily during brushing and flossing. If untreated, gingivitis can lead to periodontal disease, which has been studied extensively for its possible relation to heart disease, diabetes and pre-term birth. Researchers said that understanding how gingivitis develops and resolves on a molecular level can possibly provide critical insights into gum disease prevention, as well as new treatments.
"The study's findings demonstrate that clinical symptoms of gingivitis reflect complicated changes in cellular and molecular processes within the body," said Steven Offenbacher, D.D.S., Ph.D., the study's lead author and director of the UNC School of Dentistry-based Center for Oral and Systemic Diseases. "Understanding the thousands of individual genes and multiple systems involved in gingivitis will help explain exactly what is occurring in a person's body at the onset of the disease and how it relates to their overall health."
The build-up of plaque formed during the onset of gingivitis represents the overgrowth of bacteria as a biofilm on the teeth above and below the gum line. Biofilms can form in other parts of the body and are known to be involved with health conditions, such as urinary tract infections, ear infections and chronic sinusitis. Researchers believe learning about how the body interacts with bacteria overgrowth during gingivitis could provide insight into a variety of bio-film-associated diseases.
"Data generated by the study will be crucial in developing new approaches to treating gingivitis," said Leslie Winston, D.D.S., Ph.D., co-author of the study and Director of Professional and Scientific Relations at P&G Oral Care (makers of Crest and Oral-B). "We plan to conduct additional research to identify biomarkers of gum disease in at risk individuals and hope that this will lead to new and more advanced treatment options and preventative measures."
About the Study
The objective of this study was to understand gingivitis on a molecular level by identifying changes in gene expression taking place in the mouth during gingivitis onset and the healing process. Fourteen healthy individuals with mild gingivitis participated in the study. After baseline tooth cleanings, gingivitis was induced in each study participant, followed by the participants adhering to an oral hygiene regimen of twice-daily brushing and regular flossing. Gum tissue was collected at baseline, four weeks after the induction of gingivitis and one week after resuming the oral hygiene regimen of brushing and flossing.
Gene expression data was analyzed using gene chip technology that enabled the investigators to detect changes in the expression of more than 30,000 genes. By applying advanced genomics bioinformatics tools, the investigators were able to identify the biological pathways and gene expression patterns associated with gingivitis.
As part of the study findings, researchers identified several biological pathways triggered by the onset and healing of gingivitis, including those associated with immune response, energy metabolism, neural processes, vasculature, chemotaxis, wound healing and steroid metabolism.
Wednesday, November 25, 2009
Dentists Can Help Prevent Heart Attacks
Dentists can help to identify patients who are in danger of dying of a heart attack or stroke, reveals a new study from the Sahlgrenska Academy. Thanks to the study, six men who thought they were completely healthy were able to start preventive treatment in time.
"Dentists are really proud of their profession and feel no need to encroach upon doctors' territory," says senior dental officer and professor Mats Jontell at the Sahlgrenska Academy. "However, we wanted to find out if we as a profession could identify patients at risk of cardiovascular disease."
The study involved 200 men and women over the age of 45 who did not have any known cardiovascular problems. During a routine visit to their normal dentists in Borås and Gothenburg they were also checked out for known risk factors for cardiovascular disease.
"These risk factors are not normally manifested in the mouth, which is why the dentists went beyond their normal check-up routine," says Jontell. "They also took the patients' blood pressure and checked total cholesterol and blood sugar levels."
The risk of a fatal cardiovascular disease was calculated using a software known as HeartScore. The dentists felt that twelve men had a ten per cent risk of developing a fatal cardiovascular disease over the next ten years and advised them to see their doctors. Six of the twelve were subsequently prescribed medication to lower their blood pressure.
"Dentists regularly see a very large percentage of the Swedish population, and if there is sufficient interest they could also screen for cardiovascular risk factors which, untreated, could lead to a heart attack or stroke," says Jontell.
"Dentists are really proud of their profession and feel no need to encroach upon doctors' territory," says senior dental officer and professor Mats Jontell at the Sahlgrenska Academy. "However, we wanted to find out if we as a profession could identify patients at risk of cardiovascular disease."
The study involved 200 men and women over the age of 45 who did not have any known cardiovascular problems. During a routine visit to their normal dentists in Borås and Gothenburg they were also checked out for known risk factors for cardiovascular disease.
"These risk factors are not normally manifested in the mouth, which is why the dentists went beyond their normal check-up routine," says Jontell. "They also took the patients' blood pressure and checked total cholesterol and blood sugar levels."
The risk of a fatal cardiovascular disease was calculated using a software known as HeartScore. The dentists felt that twelve men had a ten per cent risk of developing a fatal cardiovascular disease over the next ten years and advised them to see their doctors. Six of the twelve were subsequently prescribed medication to lower their blood pressure.
"Dentists regularly see a very large percentage of the Swedish population, and if there is sufficient interest they could also screen for cardiovascular risk factors which, untreated, could lead to a heart attack or stroke," says Jontell.
Tuesday, November 24, 2009
Oral health legislation
by Sterling K. Speirn, president and CEO of the W.K. Kellogg Foundation:
The W.K. Kellogg Foundation commends Congress for its recognition of the urgent need to comprehensively and substantially strengthen oral health care for our most vulnerable children.
Most recently, the Senate version of health reform represents a high water mark for oral health legislation, with more than two dozen important provisions aimed at improving oral health care, which include:
Expanding insurance coverage for pediatric oral health services and eligibility for preventive oral health services without co-payments.
Launching new dental disease prevention initiatives including public education, school- based sealant programs in all 50 states, and research grants for dental caries management.
Addressing critical dental care workforce issues and the cultural competence and diversity of the provider teams through expanded training programs and education resources for general, pediatric and public health dentists and for the exploration of new solutions for dental professionals to reach rural and underserved areas.
Access issues are particularly severe in many rural and urban communities, and particularly impact children and families of color. The rate of untreated decay in American Indian and Alaska Native children is more than 3 times higher than that of all children in the United States. It is known that those who lack affordable health insurance are at increased risk for unmet dental needs, and together with children from poor and/or minority families, these two categories amount to 52 percent of children in this country.
Untreated dental disease many times leads to serious, life-threatening medical situations. For too long, oral health has long been separated from the rest of the body in most health policy conversations, even though oral health is essential to overall health.
We are pleased that Congress is bringing oral health into the conversation to improve our nation's overall health. These issues have historically received broad bi-partisan support, and we look forward to continued progress.
The W.K. Kellogg Foundation supports children, families, and communities as they strengthen and create conditions that propel vulnerable children to achieve success as individuals and as contributors to the larger community and society. Improving oral health for children and families is an important component of our work to improve overall health, eliminate racial disparities in health, and provide needed health care to those who are underserved.
The W.K. Kellogg Foundation commends Congress for its recognition of the urgent need to comprehensively and substantially strengthen oral health care for our most vulnerable children.
Most recently, the Senate version of health reform represents a high water mark for oral health legislation, with more than two dozen important provisions aimed at improving oral health care, which include:
Expanding insurance coverage for pediatric oral health services and eligibility for preventive oral health services without co-payments.
Launching new dental disease prevention initiatives including public education, school- based sealant programs in all 50 states, and research grants for dental caries management.
Addressing critical dental care workforce issues and the cultural competence and diversity of the provider teams through expanded training programs and education resources for general, pediatric and public health dentists and for the exploration of new solutions for dental professionals to reach rural and underserved areas.
Access issues are particularly severe in many rural and urban communities, and particularly impact children and families of color. The rate of untreated decay in American Indian and Alaska Native children is more than 3 times higher than that of all children in the United States. It is known that those who lack affordable health insurance are at increased risk for unmet dental needs, and together with children from poor and/or minority families, these two categories amount to 52 percent of children in this country.
Untreated dental disease many times leads to serious, life-threatening medical situations. For too long, oral health has long been separated from the rest of the body in most health policy conversations, even though oral health is essential to overall health.
We are pleased that Congress is bringing oral health into the conversation to improve our nation's overall health. These issues have historically received broad bi-partisan support, and we look forward to continued progress.
The W.K. Kellogg Foundation supports children, families, and communities as they strengthen and create conditions that propel vulnerable children to achieve success as individuals and as contributors to the larger community and society. Improving oral health for children and families is an important component of our work to improve overall health, eliminate racial disparities in health, and provide needed health care to those who are underserved.
Monday, November 23, 2009
Long-Term Cavity Protection
Tooth-Binding Micelles Containing Antimicrobials May Provide Long-Term Cavity Protection
A new study suggests that tooth-binding micelles (or particles) may provide long-term cavity protection by adhering to tooth surfaces and gradually releasing encapsulated antimicrobials. Formulation of a mouthwash-based delivery system is anticipated, ultimately simplifying application and increasing at-home patient compliance. The researchers from the University of Nebraska Medical Center, Omaha and the University of Florida, Gainesville report their findings in the November 2009 issue of the journal Antimicrobial Agents and Chemotherapy.
One of the main contributing factors to dental cavities is overpopulation of acid-producing bacteria in the oral cavity that causes localized destruction of compromised dental hard tissue. Due to the episodic nature of cavities, long-term benefits of periodic treatments administered during routine office visits are minimal. Other delivery systems developed to maintain drug concentrations, including bioadhesive tablets, patches, films, and gels, aren't very effective on the tooth surface and often cause irritation resulting in poor patient compliance. Emphasis on the need for therapeutic strategies that target the bacterial aspect of the disease and a delivery platform that would maintain the drug concentration on the tooth surface is warranted.
In the study tooth-binding micelles (molecular particles) were developed and encapsulated with farnesol, an antimicrobial recently found to be effective against the cavity causing bacterium Streptococcus mutans UA159. When tested on a model tooth surface the micelles were able to swiftly bind and gradually release the encapsulated farnesol. Additionally, biofilm inhibition studies of the farnesol-containing tooth-binding micelles demonstrated that they were able to inhibit S. mutans UA159 at much higher levels than untreated blank control micelles.
"A tooth-binding micelle delivery platform for the prevention and treatment of dental carries has been designed and prepared in this study," say the researchers. "It is anticipated that the tooth-binding micelles have the potential to be formulated into mouth rinses that may have the merits of simple application, cultural acceptance, and improved patient compliance."
A new study suggests that tooth-binding micelles (or particles) may provide long-term cavity protection by adhering to tooth surfaces and gradually releasing encapsulated antimicrobials. Formulation of a mouthwash-based delivery system is anticipated, ultimately simplifying application and increasing at-home patient compliance. The researchers from the University of Nebraska Medical Center, Omaha and the University of Florida, Gainesville report their findings in the November 2009 issue of the journal Antimicrobial Agents and Chemotherapy.
One of the main contributing factors to dental cavities is overpopulation of acid-producing bacteria in the oral cavity that causes localized destruction of compromised dental hard tissue. Due to the episodic nature of cavities, long-term benefits of periodic treatments administered during routine office visits are minimal. Other delivery systems developed to maintain drug concentrations, including bioadhesive tablets, patches, films, and gels, aren't very effective on the tooth surface and often cause irritation resulting in poor patient compliance. Emphasis on the need for therapeutic strategies that target the bacterial aspect of the disease and a delivery platform that would maintain the drug concentration on the tooth surface is warranted.
In the study tooth-binding micelles (molecular particles) were developed and encapsulated with farnesol, an antimicrobial recently found to be effective against the cavity causing bacterium Streptococcus mutans UA159. When tested on a model tooth surface the micelles were able to swiftly bind and gradually release the encapsulated farnesol. Additionally, biofilm inhibition studies of the farnesol-containing tooth-binding micelles demonstrated that they were able to inhibit S. mutans UA159 at much higher levels than untreated blank control micelles.
"A tooth-binding micelle delivery platform for the prevention and treatment of dental carries has been designed and prepared in this study," say the researchers. "It is anticipated that the tooth-binding micelles have the potential to be formulated into mouth rinses that may have the merits of simple application, cultural acceptance, and improved patient compliance."
Saturday, November 14, 2009
Mouth Is Indicator of Overall Health,
— One day in medical clinics, the big picture of a patient's state of health may be found in little pictures from the mouth, says Li Mao, MD, a new professor at the University of Maryland Dental School.
The mouth or oral cavity area is an excellent indicator of the whole body's health, says Mao, who is the chair of the new Department of Oncology and Diagnostic Sciences at the School.
Mao recently joined the Dental School to be at the forefront of a movement to retool dental education, he says, to make dentists practice more within the bigger health care community.
Future lung cancer prevention trials, for example, could soon be designed so that surface tissues inside the cheek could be checked to detect tobacco-induced damage in the lungs, according to a study led by Mao last year published in the journal Cancer Prevention Research.
"We hypothesized that tobacco-induced molecular alterations in the oral epithelium are similar to those in the lungs," says Mao. "This might have broader implications for using the mouth as a diagnostic indicator for general health."
University of Maryland Dental School Dean Christian S. Stohler, DMD, DrMedDent, a leader in the movement to retool dental education, says, "I feel that dentists should play a major role in prevention of cancer and Dr. Mao is the leading oral cancer researcher in the country. He crosses the bridge between medicine and dentistry. Being a physician helps expand dental health care and he wants to change how patients are being treated because his background is in head and neck cancer."
Mao believes that system biology-based approaches -- the pinpointing of molecular changes in living tissue -- is becoming an important technology in cancer studies and biomarker discovery. He says that 50 percent of oral cancer patients get diagnosed too late.
The mouth or oral cavity area is an excellent indicator of the whole body's health, says Mao, who is the chair of the new Department of Oncology and Diagnostic Sciences at the School.
Mao recently joined the Dental School to be at the forefront of a movement to retool dental education, he says, to make dentists practice more within the bigger health care community.
Future lung cancer prevention trials, for example, could soon be designed so that surface tissues inside the cheek could be checked to detect tobacco-induced damage in the lungs, according to a study led by Mao last year published in the journal Cancer Prevention Research.
"We hypothesized that tobacco-induced molecular alterations in the oral epithelium are similar to those in the lungs," says Mao. "This might have broader implications for using the mouth as a diagnostic indicator for general health."
University of Maryland Dental School Dean Christian S. Stohler, DMD, DrMedDent, a leader in the movement to retool dental education, says, "I feel that dentists should play a major role in prevention of cancer and Dr. Mao is the leading oral cancer researcher in the country. He crosses the bridge between medicine and dentistry. Being a physician helps expand dental health care and he wants to change how patients are being treated because his background is in head and neck cancer."
Mao believes that system biology-based approaches -- the pinpointing of molecular changes in living tissue -- is becoming an important technology in cancer studies and biomarker discovery. He says that 50 percent of oral cancer patients get diagnosed too late.
Monday, November 9, 2009
Mercury in Older Fillings Unlikely to be Toxic
Amid the on-going controversy over the safety of mercury-containing dental fillings, a University of Saskatchewan research team has shed new light on how the chemical forms of mercury at the surface of fillings change over time.
Their work, just published in the American Chemical Society journal Chemical Research in Toxicology, shows that the surface forms of mercury in older “silver” fillings (also known as amalgams) may be less toxic than previously thought.
“The dental amalgam on the surface of an old tooth filling may have lost as much as 95 per cent of its mercury but what’s left is in a form that is unlikely to be toxic in the body,” said U of S Canada Research Chair Graham George who led the study.
But the team cautions that due to the significant mercury loss over time, human exposure to mercury lost from fillings is “still of concern” and that further research is needed to determine when, how and in what form mercury is lost from fillings.
Mercury-based fillings have been used by dentists to repair teeth for well over a century. But in recent decades, their use has become controversial due to concerns about exposure to potentially toxic mercury.
“Mercury can potentially exist in several different chemical forms, each with a different toxicity,” said George. “Prior to our work, little was known about how the chemical forms of mercury in dental amalgam might change over time.”
The team used a special X-ray technique at the Stanford Sychrotron Radiation Lightsource to probe the amount and chemical nature of mercury at the surface of both freshly prepared metal fillings and aged fillings (about 20 years old) obtained from the U of S dental clinic’s tooth bank.
While the fresh fillings contained metallic mercury, which can be toxic, aged fillings contained a form of mercury called beta-mercuric sulfide or metacinnabar which is unlikely to be toxic in the body. For this reason, grinding or polishing during dental cleaning is unlikely to cause any toxic effects.
But of potential greater concern is the nature of the surface mercury lost from fillings. This may be due to evaporation (with subsequent inhalation and leaching of mercury into saliva), exposure to some kinds of dental hygiene products such as those containing peroxides, exposure to certain sulphur-containing foods (such as onion and garlic or coffee), or other factors.
“Possibly this missing mercury is in the less toxic form of mercury (metacinnabar) abraded from the surface of the filling. Or alternatively, it may be mercury lost prior to formation of the metacinnabar through various types of exposures,” said George.
In North America, the traditional view is that the advantages of mercury-containing amalgam outweigh any possible health risks, and for this reason, mercury-containing dental amalgams are still widely used.
Their work, just published in the American Chemical Society journal Chemical Research in Toxicology, shows that the surface forms of mercury in older “silver” fillings (also known as amalgams) may be less toxic than previously thought.
“The dental amalgam on the surface of an old tooth filling may have lost as much as 95 per cent of its mercury but what’s left is in a form that is unlikely to be toxic in the body,” said U of S Canada Research Chair Graham George who led the study.
But the team cautions that due to the significant mercury loss over time, human exposure to mercury lost from fillings is “still of concern” and that further research is needed to determine when, how and in what form mercury is lost from fillings.
Mercury-based fillings have been used by dentists to repair teeth for well over a century. But in recent decades, their use has become controversial due to concerns about exposure to potentially toxic mercury.
“Mercury can potentially exist in several different chemical forms, each with a different toxicity,” said George. “Prior to our work, little was known about how the chemical forms of mercury in dental amalgam might change over time.”
The team used a special X-ray technique at the Stanford Sychrotron Radiation Lightsource to probe the amount and chemical nature of mercury at the surface of both freshly prepared metal fillings and aged fillings (about 20 years old) obtained from the U of S dental clinic’s tooth bank.
While the fresh fillings contained metallic mercury, which can be toxic, aged fillings contained a form of mercury called beta-mercuric sulfide or metacinnabar which is unlikely to be toxic in the body. For this reason, grinding or polishing during dental cleaning is unlikely to cause any toxic effects.
But of potential greater concern is the nature of the surface mercury lost from fillings. This may be due to evaporation (with subsequent inhalation and leaching of mercury into saliva), exposure to some kinds of dental hygiene products such as those containing peroxides, exposure to certain sulphur-containing foods (such as onion and garlic or coffee), or other factors.
“Possibly this missing mercury is in the less toxic form of mercury (metacinnabar) abraded from the surface of the filling. Or alternatively, it may be mercury lost prior to formation of the metacinnabar through various types of exposures,” said George.
In North America, the traditional view is that the advantages of mercury-containing amalgam outweigh any possible health risks, and for this reason, mercury-containing dental amalgams are still widely used.
Look ma, no mercury in fillings!
Tooth enamel is hardest material in the human body because it's made almost entirely of minerals. As tough as it may be, however, enamel can be broken down by bacteria, forming cavities and eventually destroying the tooth. That's why dentists repair cavities by filling them with a material to replace the lost enamel. The most common such restorative is a material invented in the 19th-century known as amalgam -- the classic silver-black fillings many people have.
Amalgam works well because it is very durable, easy to use, and cheap. The dark fillings are sometimes unsightly, however, and they contain mercury. Because of the mercury, amalgam has raised health and environmental questions -- though according to the American Dental Association, the scientific consensus is that the material poses no health hazards. Dentists would love to have a perfectly white material that mimics natural enamel for repairing cavities in teeth, but for the most part, they still use amalgam. Other filling materials have been developed in recent years, but they often have problems with shrinkage or durability.
Kent Coulter and his colleagues at Southwest Research Institute in San Antonio have developed a new proof-of-concept dental restorative material under a program funded by the National Institutes of Health that seeks to replace amalgam with other materials. They will describe the material on November 9 at a meeting of the scientific society AVS in San Jose. The new fillings are made with a plastic-like material containing zirconia nanoplatelets -- tiny crystals made of the same sort of material used to make fake diamonds and gem stones. Unlike their costume jewelry cousins, the zirconia nanoplatelets super hard because of a difference in the particular arrangements of the atoms in the material.
Coulter and his colleagues designed a way to make a roll of this material under vacuum. They envision that this material would be lifted from the roll and packed in a dental cavity and then cured -- using an ultraviolet lamp or some other means -- so that it hardens in place without shrinking. In San Jose, they will describe how they have been developing and testing the performance of these materials in the laboratory. Its use is still several years away from the dentist's chair, however, and the next steps will be first to see if the new material performs as hoped for people with cavities.
Abstract: http://www.avssymposium.org/Open/SearchPapers.aspx?PaperNumber=NS+BI-MoM-1
Amalgam works well because it is very durable, easy to use, and cheap. The dark fillings are sometimes unsightly, however, and they contain mercury. Because of the mercury, amalgam has raised health and environmental questions -- though according to the American Dental Association, the scientific consensus is that the material poses no health hazards. Dentists would love to have a perfectly white material that mimics natural enamel for repairing cavities in teeth, but for the most part, they still use amalgam. Other filling materials have been developed in recent years, but they often have problems with shrinkage or durability.
Kent Coulter and his colleagues at Southwest Research Institute in San Antonio have developed a new proof-of-concept dental restorative material under a program funded by the National Institutes of Health that seeks to replace amalgam with other materials. They will describe the material on November 9 at a meeting of the scientific society AVS in San Jose. The new fillings are made with a plastic-like material containing zirconia nanoplatelets -- tiny crystals made of the same sort of material used to make fake diamonds and gem stones. Unlike their costume jewelry cousins, the zirconia nanoplatelets super hard because of a difference in the particular arrangements of the atoms in the material.
Coulter and his colleagues designed a way to make a roll of this material under vacuum. They envision that this material would be lifted from the roll and packed in a dental cavity and then cured -- using an ultraviolet lamp or some other means -- so that it hardens in place without shrinking. In San Jose, they will describe how they have been developing and testing the performance of these materials in the laboratory. Its use is still several years away from the dentist's chair, however, and the next steps will be first to see if the new material performs as hoped for people with cavities.
Abstract: http://www.avssymposium.org/Open/SearchPapers.aspx?PaperNumber=NS+BI-MoM-1
Thursday, November 5, 2009
Dentists Can Identify Risk for Heart Attack
A new study indicates dentists can play a potentially life-saving role in health care by identifying patients at risk of fatal heart attacks and referring them to physicians for further evaluation.
Published in the November issue of the Journal of the American Dental Association, followed 200 patients (101 women and 99 men) in private dental practices in Sweden whose dentists used a computerized system, “HeartScore,” to calculate the risk of a patient dying from a cardiovascular event within a 10-year period.
Designed by the European Society of Cardiology, HeartScore measures cardiovascular disease risk in persons aged 40-65 by factoring the person’s age, sex, total cholesterol level, systolic blood pressure and smoking status.
Patients with HeartScores of 10 percent or higher, meaning they had a 10 percent or higher risk of having a fatal heart attack or stroke within a 10-year period, were told by dentists to seek medical advice regarding their condition.
Twelve patients in the study, all of them men, had HeartScores of 10 percent or higher. All women participating in the study had HeartScores of 5 percent or less.
Of the 12 male patients with HeartScores of 10 percent or higher, nine sought further evaluation by a medical care provider who decided that intervention was indicated for six of the patients. Two patients did not follow the dentist’s recommendation to seek further medical evaluation and one patient was only encouraged by his dentist to discontinue smoking. Physicians for three patients were not able to confirm their risk for cardiovascular disease,
All 200 patients enrolled in the study were 45 years of age or older with no history of cardiovascular disease, medications for high blood pressure, high cholesterol or diabetes and had not visited a physician during the previous year to assess their glucose, cholesterol or blood pressure levels.
The study’s authors conclude that oral health care professionals can identify patients who are unaware of their risk of developing serious complications as a result of cardiovascular disease and who are in need of medical interventions.
According to the authors, “With emerging data suggesting an association between oral and non-oral diseases, and with the possibility of performing chairside screening tests for diseases such as cardiovascular disease and diabetes, oral health care professionals may find themselves in an opportune position to enhance the overall health and well-being of their patients.”
Published in the November issue of the Journal of the American Dental Association, followed 200 patients (101 women and 99 men) in private dental practices in Sweden whose dentists used a computerized system, “HeartScore,” to calculate the risk of a patient dying from a cardiovascular event within a 10-year period.
Designed by the European Society of Cardiology, HeartScore measures cardiovascular disease risk in persons aged 40-65 by factoring the person’s age, sex, total cholesterol level, systolic blood pressure and smoking status.
Patients with HeartScores of 10 percent or higher, meaning they had a 10 percent or higher risk of having a fatal heart attack or stroke within a 10-year period, were told by dentists to seek medical advice regarding their condition.
Twelve patients in the study, all of them men, had HeartScores of 10 percent or higher. All women participating in the study had HeartScores of 5 percent or less.
Of the 12 male patients with HeartScores of 10 percent or higher, nine sought further evaluation by a medical care provider who decided that intervention was indicated for six of the patients. Two patients did not follow the dentist’s recommendation to seek further medical evaluation and one patient was only encouraged by his dentist to discontinue smoking. Physicians for three patients were not able to confirm their risk for cardiovascular disease,
All 200 patients enrolled in the study were 45 years of age or older with no history of cardiovascular disease, medications for high blood pressure, high cholesterol or diabetes and had not visited a physician during the previous year to assess their glucose, cholesterol or blood pressure levels.
The study’s authors conclude that oral health care professionals can identify patients who are unaware of their risk of developing serious complications as a result of cardiovascular disease and who are in need of medical interventions.
According to the authors, “With emerging data suggesting an association between oral and non-oral diseases, and with the possibility of performing chairside screening tests for diseases such as cardiovascular disease and diabetes, oral health care professionals may find themselves in an opportune position to enhance the overall health and well-being of their patients.”
Wednesday, November 4, 2009
Hybrid composite for root canal treatment
Unrelenting toothache means a visit to the dentist is inevitable, and if the tooth decay is really bad root canal treatment is often the only option. The dentist first removes the nerve completely and then closes the ensuing canal with a filler. This must be airtight to prevent bacteria from entering and causing renewed inflammation. On the other hand, the material must also be removable. If the natural crown is severely damaged, the dentist will anchor a root post in the previously filled canal using dental cement. The post provides an anchor for the composite material used to rebuild the remaining part of the tooth, the core, which serves as the base for the core build-up material and the prosthetik treatment e.g. a crown. In root canal procedures, therefore, various materials are combined, each fulfilling different requirements. The problem is that the materials are not always compatible with each other or do not bond properly with the hard dental tissue. As a result, the post may break, the core and the crown may not adhere to the post properly, and the expensive crown may need replacing. Such faults are not rare and generally occur in the single-digit percent range.
Researchers at the Fraunhofer Institute for Silicate Research ISC in Würzburg working in collaboration with their research partners at VOCO GmbH have now developed a material that can be used for all the components used in root canal treatment. "The basis of this material is provided by ORMOCER®s," explains Dr. Herbert Wolter, group manager at the ISC. "We have combined these ORMOCER®s with various nano- and microparticles to achieve the highly diverse properties needed." Materials used in filling the root canal, for instance, should not shrink as they harden, should form an airtight bond with the dental material and be visible in x-rays. The material used to rebuild the tooth, on the other hand, should have the same properties as the tooth itself. "Hybrid materials are well suited to these requirements. For instance, they only shrink by about 1.3 percent as they harden, while standard materials generally shrink by 2 to 4 percent. ORMOCER®s can also be adapted to adhere to the different parts of the tooth," says Wolter. VOCO GmbH is already producing dental preparations and product development is making good progress. Market launch could therefore be just a few years away.
Researchers at the Fraunhofer Institute for Silicate Research ISC in Würzburg working in collaboration with their research partners at VOCO GmbH have now developed a material that can be used for all the components used in root canal treatment. "The basis of this material is provided by ORMOCER®s," explains Dr. Herbert Wolter, group manager at the ISC. "We have combined these ORMOCER®s with various nano- and microparticles to achieve the highly diverse properties needed." Materials used in filling the root canal, for instance, should not shrink as they harden, should form an airtight bond with the dental material and be visible in x-rays. The material used to rebuild the tooth, on the other hand, should have the same properties as the tooth itself. "Hybrid materials are well suited to these requirements. For instance, they only shrink by about 1.3 percent as they harden, while standard materials generally shrink by 2 to 4 percent. ORMOCER®s can also be adapted to adhere to the different parts of the tooth," says Wolter. VOCO GmbH is already producing dental preparations and product development is making good progress. Market launch could therefore be just a few years away.
Videos Online For Patient Education
Family & Cosmetic Dentistry of Fairfield CT offers videos and images for dental conditions and procedures, enabling the office to make patient education very easy with visual, engaging treatment plans, for greater comprehension and compliance. To help patients better understand procedures, and to put them at ease, Dr. Mariana Conant has launched 3 new websites to help educate her patients looking for answers on the following 3 major procedures; Dental Implants, Tooth Whitening, and Braces.
http://www.dentalimplantsfairfeild.com - explains in detail the process in which a missing tooth is fixed as well as information on dentures and bridges:
http://www.toothwhiteingfairfeild.com - offers ideas on whitening your smile.
http://www.clearbracesfairfield.com - teaches you everything you need to know about braces, both metal and clear brace technologies.
Studies show that most people put off visiting a dental office because they aren't sure what to expect and they are terrified. The videos offer details on exactly what you can expect, in a clear and informative format.
Dr. Mariana Conant's office created the 3 websites to help educate patients. Dr. Conant said "Over the years we have watched expressions of fear, doubt and worry cross our patient's face when we mention certain dental procedures". "With the launch of our website patients can watch in the comfort of their own home with calm and relief as they feel no pressure or anxiety."
Family & Cosmetic Dentistry of Fairfield offers cosmetic procedures such as ZOOM! Whitening and Dr. Mariana Conant also performs cosmetic treatments such as Fillings, Crowns, Bridges, Dentures, Dental Implants & Veneers.
http://www.dentalimplantsfairfeild.com - explains in detail the process in which a missing tooth is fixed as well as information on dentures and bridges:
http://www.toothwhiteingfairfeild.com - offers ideas on whitening your smile.
http://www.clearbracesfairfield.com - teaches you everything you need to know about braces, both metal and clear brace technologies.
Studies show that most people put off visiting a dental office because they aren't sure what to expect and they are terrified. The videos offer details on exactly what you can expect, in a clear and informative format.
Dr. Mariana Conant's office created the 3 websites to help educate patients. Dr. Conant said "Over the years we have watched expressions of fear, doubt and worry cross our patient's face when we mention certain dental procedures". "With the launch of our website patients can watch in the comfort of their own home with calm and relief as they feel no pressure or anxiety."
Family & Cosmetic Dentistry of Fairfield offers cosmetic procedures such as ZOOM! Whitening and Dr. Mariana Conant also performs cosmetic treatments such as Fillings, Crowns, Bridges, Dentures, Dental Implants & Veneers.
Tuesday, November 3, 2009
Guideline on oral health for people with diabetes
New clinical guidelines released by the International Diabetes Foundation (IDF) emphasize the importance of periodontal health for people with diabetes. Diabetes affects approximately 246 million people worldwide, and this number is only expected to increase. The IDF is an organization of 200 national diabetes associations from 160 countries.
The new IDF oral health clinical guideline supports what research has already suggested: that management of periodontal disease - which affects the gums and other supporting tissues around the teeth - can help reduce the risk of developing diabetes; and can also help people with diabetes control their blood sugar levels. Studies have suggested there is a two-way relationship between diabetes and periodontal disease, and the IDF guideline outlines helpful guidance for health professionals who treat people living with and at risk for diabetes.
The IDF guideline contains clinical recommendations on periodontal care, written in collaboration with the World Dental Federation (FDI), that encourage health professionals to conduct annual inquiries for symptoms of periodontal disease such as swollen or red gums, or bleeding during tooth brushing; and to educate their patients with diabetes about the implications of the condition on oral health, and especially periodontal health.
"Everyone should maintain healthy teeth and gums to avoid periodontal disease, but people with diabetes should pay extra attention," said Samuel Low, DDS, MS, Associate Dean and professor of periodontology at the University of Florida College of Dentistry, and President of the American Academy of Periodontology (AAP). "Periodontal disease triggers the body's inflammatory response which can affect insulin sensitivity and ultimately lead to unhealthy blood sugar levels. Establishing routine periodontal care is one way to help keep diabetes under control."
In recognition of American Diabetes Month, the American Academy of Periodontology commends the International Diabetes Foundation on the release of the Guideline on Oral Health for People with Diabetes, and supports its encouragement of continued collaboration and communication between diabetes and oral healthcare professionals.
In addition to helping increase awareness about the importance of oral care for people with diabetes, Dr. Low believes the guideline presents more opportunities for medicine and dentistry to work together. "I know that these clinical recommendations will be helpful for those professionals who work with and treat people with diabetes. I also encourage the medical and dental communities to work together to provide the best possible care for our patients."
The new IDF oral health clinical guideline supports what research has already suggested: that management of periodontal disease - which affects the gums and other supporting tissues around the teeth - can help reduce the risk of developing diabetes; and can also help people with diabetes control their blood sugar levels. Studies have suggested there is a two-way relationship between diabetes and periodontal disease, and the IDF guideline outlines helpful guidance for health professionals who treat people living with and at risk for diabetes.
The IDF guideline contains clinical recommendations on periodontal care, written in collaboration with the World Dental Federation (FDI), that encourage health professionals to conduct annual inquiries for symptoms of periodontal disease such as swollen or red gums, or bleeding during tooth brushing; and to educate their patients with diabetes about the implications of the condition on oral health, and especially periodontal health.
"Everyone should maintain healthy teeth and gums to avoid periodontal disease, but people with diabetes should pay extra attention," said Samuel Low, DDS, MS, Associate Dean and professor of periodontology at the University of Florida College of Dentistry, and President of the American Academy of Periodontology (AAP). "Periodontal disease triggers the body's inflammatory response which can affect insulin sensitivity and ultimately lead to unhealthy blood sugar levels. Establishing routine periodontal care is one way to help keep diabetes under control."
In recognition of American Diabetes Month, the American Academy of Periodontology commends the International Diabetes Foundation on the release of the Guideline on Oral Health for People with Diabetes, and supports its encouragement of continued collaboration and communication between diabetes and oral healthcare professionals.
In addition to helping increase awareness about the importance of oral care for people with diabetes, Dr. Low believes the guideline presents more opportunities for medicine and dentistry to work together. "I know that these clinical recommendations will be helpful for those professionals who work with and treat people with diabetes. I also encourage the medical and dental communities to work together to provide the best possible care for our patients."
Friday, October 30, 2009
Ohio and Georgia Pay Less for Dental Care
than the National Average
The annual amount spent by Georgians and Ohioans or their insurers for dental care in 2006 averaged about $150 less than the national average of $607, according to the latest News and Numbers from the Agency for Healthcare Research and Quality. The average annual dental expenditure for each Georgian who had dental care was $466, while for Ohioans, it was $474.
The federal agency’s analysis of average annual dental expenditures in the 10 states with the highest populations in 2006 also found that:
• Michigan had the highest proportion of residents with dental expenses (52.5 percent) and Texas had the least (30 percent).
• Compared to the national average of 49 percent for out-of-pocket payment for dental care, Floridians paid more (62.5 percent) and Pennsylvanians paid less (42 percent).
• Nationally, private insurers paid 43 percent of all dental expenditures.
AHRQ, which is part of the U.S. Department of Health and Human Services, improves the quality, safety, efficiency, and effectiveness of health care for all Americans. The data in this AHRQ News and Numbers summary are taken from the Medical Expenditure Panel Survey (MEPS), a detailed source of information on the health services used by Americans, the frequency with which they are used, the cost of those services, and how they are paid.
For more information, go to Dental Expenditures in the 10 Largest States, 2006.
The annual amount spent by Georgians and Ohioans or their insurers for dental care in 2006 averaged about $150 less than the national average of $607, according to the latest News and Numbers from the Agency for Healthcare Research and Quality. The average annual dental expenditure for each Georgian who had dental care was $466, while for Ohioans, it was $474.
The federal agency’s analysis of average annual dental expenditures in the 10 states with the highest populations in 2006 also found that:
• Michigan had the highest proportion of residents with dental expenses (52.5 percent) and Texas had the least (30 percent).
• Compared to the national average of 49 percent for out-of-pocket payment for dental care, Floridians paid more (62.5 percent) and Pennsylvanians paid less (42 percent).
• Nationally, private insurers paid 43 percent of all dental expenditures.
AHRQ, which is part of the U.S. Department of Health and Human Services, improves the quality, safety, efficiency, and effectiveness of health care for all Americans. The data in this AHRQ News and Numbers summary are taken from the Medical Expenditure Panel Survey (MEPS), a detailed source of information on the health services used by Americans, the frequency with which they are used, the cost of those services, and how they are paid.
For more information, go to Dental Expenditures in the 10 Largest States, 2006.
Tuesday, October 27, 2009
Alkaline substances can damage teeth
It has long been known that acids can erode tooth enamel but a new Swedish study from the Sahlgrenska Academy at the University of Gothenburg shows that strong alkaline substances can damage teeth too - substances with high pH values can destroy parts of the organic content of the tooth, leaving the enamel more vulnerable.
The study was carried out at the Department of Occupational and Environmental Medicine at the Sahlgrenska Academy and published in the Journal of Dentistry.
"The study shows that exposure to alkaline substances can result in damaged teeth, but that the process is different to that caused by exposure to acidic drinks or acidic industrial vapours," says Fabian Taube, occupational hygienist and one of the researchers behind the study.
It was occupational injuries from reconditioning of cars that attracted the attention of the researchers. The common denominator was exposure to an alkaline degreaser that was sprayed onto various parts of the cars. The spray turned out to have a pH value of between 12 and 14, which is very alkaline.
"Exposure to this substance damaged the surface of the teeth resulting in “flaked” enamel," says Jörgen Norén, professor/senior dental officer at the Sahlgrenska Academy. "This type of damage markedly increases the risk of caries and other dental damage."
Alkaline degreasers are used in the food industry, among other things to clean professional kitchens, but are also common in car care industry and to remove vandalism painting.
"Occupational damage to teeth from exposure to alkaline substances is probably not as common as damage from acidic substances, but it becomes a problem when employers fail to inform employees of the risks or do not give them access to the right protective equipment," says Taube.
The study exposed extracted teeth to degreasers and other alkaline solutions. Enamel samples were then examined with a scanning electron microscope and analysed using various spectroscopic methods. The researchers found that organic material on the surface of the tooth dissolves rapidly. The results indicate that the organic components of the enamel are also affected, as the enamel becomes more porous.
"However, we were not able to show that alkaline substances change the composition of the minerals that constitute the main component of enamel," says Taube. "In that sense, it differs from the effects of exposure to acids."
The study was carried out with funding from the Swedish Council for Working Life and Social Research (FAS) and the Magnus Bergvall Foundation, among others.
TOOTH ENAMEL
Enamel, the body's hardest tissue, forms a layer over the teeth that is up to two millimetres thick. Just two per cent of the enamel is organic material, with the rest comprising various minerals and water. The organic component is made up of protein, lipids and citrate, whilst the inorganic component is made up of calcium hydroxylapatite and calcium fluorapatite.
The study was carried out at the Department of Occupational and Environmental Medicine at the Sahlgrenska Academy and published in the Journal of Dentistry.
"The study shows that exposure to alkaline substances can result in damaged teeth, but that the process is different to that caused by exposure to acidic drinks or acidic industrial vapours," says Fabian Taube, occupational hygienist and one of the researchers behind the study.
It was occupational injuries from reconditioning of cars that attracted the attention of the researchers. The common denominator was exposure to an alkaline degreaser that was sprayed onto various parts of the cars. The spray turned out to have a pH value of between 12 and 14, which is very alkaline.
"Exposure to this substance damaged the surface of the teeth resulting in “flaked” enamel," says Jörgen Norén, professor/senior dental officer at the Sahlgrenska Academy. "This type of damage markedly increases the risk of caries and other dental damage."
Alkaline degreasers are used in the food industry, among other things to clean professional kitchens, but are also common in car care industry and to remove vandalism painting.
"Occupational damage to teeth from exposure to alkaline substances is probably not as common as damage from acidic substances, but it becomes a problem when employers fail to inform employees of the risks or do not give them access to the right protective equipment," says Taube.
The study exposed extracted teeth to degreasers and other alkaline solutions. Enamel samples were then examined with a scanning electron microscope and analysed using various spectroscopic methods. The researchers found that organic material on the surface of the tooth dissolves rapidly. The results indicate that the organic components of the enamel are also affected, as the enamel becomes more porous.
"However, we were not able to show that alkaline substances change the composition of the minerals that constitute the main component of enamel," says Taube. "In that sense, it differs from the effects of exposure to acids."
The study was carried out with funding from the Swedish Council for Working Life and Social Research (FAS) and the Magnus Bergvall Foundation, among others.
TOOTH ENAMEL
Enamel, the body's hardest tissue, forms a layer over the teeth that is up to two millimetres thick. Just two per cent of the enamel is organic material, with the rest comprising various minerals and water. The organic component is made up of protein, lipids and citrate, whilst the inorganic component is made up of calcium hydroxylapatite and calcium fluorapatite.
Wednesday, September 30, 2009
Reducing early childhood caries by 77 percent
Training clinicians helps reduce rates of early childhood cavities
Researchers at Boston University School of Medicine (BUSM) have found that pediatricians provided with the proper communication, educational and information technology tools and training could reduce the rates of children developing early childhood caries (ECC) or cavities by 77 percent. This study appears in the October issue of the Journal Medical Care.
ECC, the most common chronic illness among children, can lead to serious complications if untreated, including abscesses requiring costly surgery. Infection and pain caused by ECC can also impair growth, weight gain and limit school attendance.
BUSM researchers provided pediatric clinicians with communication skills training to help them more effectively counsel parents and caregivers to reduce children's ECC risk. Pediatricians as well as clinical nurses participated in a one hour study training session, and they were also provided with educational brochures to give to parents. The electronic medical record was also adapted to prompt clinicians to remember to counsel. After the educational program, a simultaneous recruitment of children affected with ECC was conducted at a comparison site, where the clinicians did not receive training.
Parents and caregivers of children aged six months to five years were asked to participate in a clinical exam and interview that consisted of a series of questions inquiring about the parent or caregiver's discussion with the child's doctor or nurse. This interview assessed the degree the clinician covered the topics on which they had been trained to counsel regarding ECC risk reduction. This process was repeated approximately one year later.
The findings show that providers at the intervention site had greater knowledge and conducted more counseling, and patients at that site had significantly reduced odds of developing ECC over time. "Pediatric clinicians at Boston Medical Center are committed to children's oral health, and to addressing the deficit in clinical preparation to help prevent ECC," explained lead author, Nancy R. Kressin, PhD, an associate professor of General Internal Medicine at Boston University School of Medicine. "We developed and implemented a multi-faceted pediatric practice based intervention where children especially vulnerable to ECC received enhanced care to prevent this disease from occurring or reoccurring, and it had marked effects on reducing children's rates of developing ECC" said Kressin.
###
This study was funded by the National Institutes of Health the National Institute of Dental and Craniofacial Research.
Researchers at Boston University School of Medicine (BUSM) have found that pediatricians provided with the proper communication, educational and information technology tools and training could reduce the rates of children developing early childhood caries (ECC) or cavities by 77 percent. This study appears in the October issue of the Journal Medical Care.
ECC, the most common chronic illness among children, can lead to serious complications if untreated, including abscesses requiring costly surgery. Infection and pain caused by ECC can also impair growth, weight gain and limit school attendance.
BUSM researchers provided pediatric clinicians with communication skills training to help them more effectively counsel parents and caregivers to reduce children's ECC risk. Pediatricians as well as clinical nurses participated in a one hour study training session, and they were also provided with educational brochures to give to parents. The electronic medical record was also adapted to prompt clinicians to remember to counsel. After the educational program, a simultaneous recruitment of children affected with ECC was conducted at a comparison site, where the clinicians did not receive training.
Parents and caregivers of children aged six months to five years were asked to participate in a clinical exam and interview that consisted of a series of questions inquiring about the parent or caregiver's discussion with the child's doctor or nurse. This interview assessed the degree the clinician covered the topics on which they had been trained to counsel regarding ECC risk reduction. This process was repeated approximately one year later.
The findings show that providers at the intervention site had greater knowledge and conducted more counseling, and patients at that site had significantly reduced odds of developing ECC over time. "Pediatric clinicians at Boston Medical Center are committed to children's oral health, and to addressing the deficit in clinical preparation to help prevent ECC," explained lead author, Nancy R. Kressin, PhD, an associate professor of General Internal Medicine at Boston University School of Medicine. "We developed and implemented a multi-faceted pediatric practice based intervention where children especially vulnerable to ECC received enhanced care to prevent this disease from occurring or reoccurring, and it had marked effects on reducing children's rates of developing ECC" said Kressin.
###
This study was funded by the National Institutes of Health the National Institute of Dental and Craniofacial Research.
Tuesday, September 29, 2009
American Dental Association Podcast Programs
The American Dental Association (ADA) is launching “Straight from the Mouth,” a new video podcast series for the public, to provide oral health information in amusing three to five-minute Webisodes.
Posted monthly, the podcasts are a new resource for people seeking health information online and will be available on iTunes and the ADA Web site ADA.org. The podcasts feature such dental health topics as tooth whitening, overcoming dental anxiety, dental care for children and dental care while traveling to other countries.
“We’re having a lot of fun with these, but at the heart of each episode is sound clinical and scientific information to help people maintain their oral health,” said Ruchi Nijjar Sahota, D.D.S., a practicing dentist in Freemont, Calif., who co-hosts the show with Eric Grove, D.D.S, who graduated from Loma Linda University School of Dentistry just this year.
The first episode of “Straight from the Mouth” focuses on overcoming dental anxiety.
“Movies and TV shows make fun of dental anxiety,” said Dr. Grove. “But people who suffer from it also can suffer the consequences of neglecting their teeth and gums, and that’s no joke. In our podcast, we joke around a little, but we also offer practical tips to help people overcome anxiety. Regular dental care is important, and dentists want to make their patients’ visits as comfortable as possible.”
Posted monthly, the podcasts are a new resource for people seeking health information online and will be available on iTunes and the ADA Web site ADA.org. The podcasts feature such dental health topics as tooth whitening, overcoming dental anxiety, dental care for children and dental care while traveling to other countries.
“We’re having a lot of fun with these, but at the heart of each episode is sound clinical and scientific information to help people maintain their oral health,” said Ruchi Nijjar Sahota, D.D.S., a practicing dentist in Freemont, Calif., who co-hosts the show with Eric Grove, D.D.S, who graduated from Loma Linda University School of Dentistry just this year.
The first episode of “Straight from the Mouth” focuses on overcoming dental anxiety.
“Movies and TV shows make fun of dental anxiety,” said Dr. Grove. “But people who suffer from it also can suffer the consequences of neglecting their teeth and gums, and that’s no joke. In our podcast, we joke around a little, but we also offer practical tips to help people overcome anxiety. Regular dental care is important, and dentists want to make their patients’ visits as comfortable as possible.”
Tuesday, September 22, 2009
Stem cell studies at the U. of MD. Dental School
New stem cell studies at the University of Maryland Dental School demonstrate that surgeons could one day routinely use strong, moldable, and injectable pastes to regenerate needed bone tissue to repair broken bones, fractures, genetic defects, even combat bone wounds.
Human stem cells seeded in a tissue engineering scaffolding exhibited “excellent attachment and osteogenic differentiation,” which is the process of laying down new bone material.
The researchers said the new findings buoy hopes that an injectable paste of stem cells will be available one day to fill any shape of cavity from bone defects, breaks or wounds by regenerating needed bone tissue.
In test tube studies, stem cells from bone marrow, when placed into an injectable scaffold of calcium phosphate and chitosan, started growing and forming minerals needed for new bone tissue.
Xu, an associate professor, is the principal investigator of a $230,000 grant from the Maryland Stem Cell Research Fund for “Stem Cell Delivery via Injectable, Nano-apatite Scaffolds for Bone Engineering,” and a $1.84 million grant from the National Institute of Dental and Craniofacial Research.
The Dental School researchers have so far tested four scaffolding materials for gripping and holding the stem cells. “Which of the materials will be used in a commercial product really depends on where you want to place the material, whether in the jaw bone, the cranium or other bones,” said Weir, a research assistant professor.
Weir said, “Ultimately we want this to be an injectable paste so we can put it into voids that are not square, rectangular or circular, that they are irregular shapes that need to be filled. The paste will include the cells.”
Xu added that such a product could also be used in periodontal bone repair, mandibular and maxillary ridge augmentation, reconstruction of frontal sinus and craniofacial skeletal defects, and other stress-bearing orthopedic applications. After a tumor removal or traffic accident, there may be a need to repair the damage or void left. It will beneficial, he said, to have a paste that can be shaped easily to achieve a high degree of aesthetics. After shaping, the paste hardens to form a solid scaffold full of pores and channels and still containing stem cells throughout, still living and growing to form new bone. Eventually the scaffold material degrades and is replaced entirely by new bone tissue grown from the stem cells.
The researchers found that a significant number of the cells were alive after a few weeks in the scaffolding material. They then discovered that the cells were differentiating into osteoblasts, essentially turning into bone cells. (From Greek words for bone, an osteoblast cell is responsible for bone formation.)
After staining the scaffold, the researchers found the osteoblasts forming “a lot” of the mineral, which then forms the bone after only 21 days, said Weir. In a subsequent experiment, the cells survived even better when mixed in a gel of the scaffolding material.
The researchers have recorded similar success with umbilical cord-derived stem cells, which “appear to be more potent in terms of growth and transforming into osteoblasts on the scaffold than the cells from bone marrow,” said Xu. It is likely that the umbilical cord cells are more vital because they are younger than stem cells obtained from the adult bone marrow and in theory will act more quickly to repair wounds or bone defects.
Xu explained: “When a 16-year-old breaks a bone, it usually takes a few weeks to heal. In a 60-year-old, it likely takes a few months. Umbilical cord stem cells are only 9 months old and hence are fast in healing.” Xu said human umbilical cord stem cells have the promise to be a superior alternative to bone marrow-derived stem cells, the latter requiring an invasive procedure to harvest. For combat medics, the umbilical cord derived stem cells could potentially be on the shelf and used in the field without causing immunuorejection, said Xu.
Xu said that after a literature search, he believes his laboratory is the first to investigate the seeding of umbilical cord-derived stem cells in injectable and load-bearing scaffolding for bone tissue engineering.
“We are excited about the promise of encapsulating umbilical cord stem cells in an injectable scaffold for stem cell delivery and bone regeneration.” Xu said. “Our research is still in an early stage. We will perform more systematic investigations and animal studies. If indeed human umbilical cord stem cells delivered using injectable scaffolds are more effective in bone regeneration than the commonly studied bone marrow stem cells, it will broadly impact the field of stem cell-based regenerative medicine.”
Human stem cells seeded in a tissue engineering scaffolding exhibited “excellent attachment and osteogenic differentiation,” which is the process of laying down new bone material.
The researchers said the new findings buoy hopes that an injectable paste of stem cells will be available one day to fill any shape of cavity from bone defects, breaks or wounds by regenerating needed bone tissue.
In test tube studies, stem cells from bone marrow, when placed into an injectable scaffold of calcium phosphate and chitosan, started growing and forming minerals needed for new bone tissue.
Xu, an associate professor, is the principal investigator of a $230,000 grant from the Maryland Stem Cell Research Fund for “Stem Cell Delivery via Injectable, Nano-apatite Scaffolds for Bone Engineering,” and a $1.84 million grant from the National Institute of Dental and Craniofacial Research.
The Dental School researchers have so far tested four scaffolding materials for gripping and holding the stem cells. “Which of the materials will be used in a commercial product really depends on where you want to place the material, whether in the jaw bone, the cranium or other bones,” said Weir, a research assistant professor.
Weir said, “Ultimately we want this to be an injectable paste so we can put it into voids that are not square, rectangular or circular, that they are irregular shapes that need to be filled. The paste will include the cells.”
Xu added that such a product could also be used in periodontal bone repair, mandibular and maxillary ridge augmentation, reconstruction of frontal sinus and craniofacial skeletal defects, and other stress-bearing orthopedic applications. After a tumor removal or traffic accident, there may be a need to repair the damage or void left. It will beneficial, he said, to have a paste that can be shaped easily to achieve a high degree of aesthetics. After shaping, the paste hardens to form a solid scaffold full of pores and channels and still containing stem cells throughout, still living and growing to form new bone. Eventually the scaffold material degrades and is replaced entirely by new bone tissue grown from the stem cells.
The researchers found that a significant number of the cells were alive after a few weeks in the scaffolding material. They then discovered that the cells were differentiating into osteoblasts, essentially turning into bone cells. (From Greek words for bone, an osteoblast cell is responsible for bone formation.)
After staining the scaffold, the researchers found the osteoblasts forming “a lot” of the mineral, which then forms the bone after only 21 days, said Weir. In a subsequent experiment, the cells survived even better when mixed in a gel of the scaffolding material.
The researchers have recorded similar success with umbilical cord-derived stem cells, which “appear to be more potent in terms of growth and transforming into osteoblasts on the scaffold than the cells from bone marrow,” said Xu. It is likely that the umbilical cord cells are more vital because they are younger than stem cells obtained from the adult bone marrow and in theory will act more quickly to repair wounds or bone defects.
Xu explained: “When a 16-year-old breaks a bone, it usually takes a few weeks to heal. In a 60-year-old, it likely takes a few months. Umbilical cord stem cells are only 9 months old and hence are fast in healing.” Xu said human umbilical cord stem cells have the promise to be a superior alternative to bone marrow-derived stem cells, the latter requiring an invasive procedure to harvest. For combat medics, the umbilical cord derived stem cells could potentially be on the shelf and used in the field without causing immunuorejection, said Xu.
Xu said that after a literature search, he believes his laboratory is the first to investigate the seeding of umbilical cord-derived stem cells in injectable and load-bearing scaffolding for bone tissue engineering.
“We are excited about the promise of encapsulating umbilical cord stem cells in an injectable scaffold for stem cell delivery and bone regeneration.” Xu said. “Our research is still in an early stage. We will perform more systematic investigations and animal studies. If indeed human umbilical cord stem cells delivered using injectable scaffolds are more effective in bone regeneration than the commonly studied bone marrow stem cells, it will broadly impact the field of stem cell-based regenerative medicine.”
Friday, September 11, 2009
International Report: No Amalgam Bans in Effect
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Dentists around the world are using amalgams (silver fillings)
every day to fill decayed teeth, despite some erroneous news reports
stating that many countries have banned the use of amalgams.
International dental experts meeting recently at the American Dental
Association (ADA) headquarters in Chicago discussed the use of amalgam
in their respective countries.
Sweden is often cited as an example of a country that has banned
amalgam, but that is not true, according to Professor Maud Bergman of
University. Professor Bergman said it is unlikely Sweden will ban the
use of amalgams in the near future. Nor do Sweden's neighbors, Norway
and Denmark ban the use of the filling material. Representatives from
Germany and the Netherlands also said amalgam is not banned in their
countries. Dr. Elmar Reich of Germany's University of Saarland said
that some limited restrictions on the use of amalgam may even be
loosened when the classification of amalgam changes in mid-1998 to a
medical device from its current designation as a therapeutic
agent. Dentists from South Africa, Australia, New Zealand, Japan and
Canada reported that amalgam is not banned in their countries either.
Although the Canadian government has recommended some restrictions on
the use of amalgam, the Canadian Dental Association (CDA) has requested
that the government provide scientific documentation to back up some of
the recommendations that the CDA is questioning.
The World Health Organization, FDI World Dental Federation and the ADA
all support the continued use of dental amalgam as a safe, durable and
cost-effective material to restore teeth based on current scientific
knowledge. There is currently no credible scientific evidence that
exposure to mercury from amalgam restorations poses a serious health
risk in humans, except for the exceedingly small number of allergic
reactions. In 150 years of use, there have been only about 100
documented cases of allergic reactions to amalgam in the dental
literature. A joint WHO/FDI meeting is scheduled in Geneva,
Switzerland, in March, 1997, to review the latest scientific evidence on
the safety of dental amalgam.
Contact Newswise
Register
PressPass
Libraries
Latest News
Science News
Medical News
Life News
Business News
Video/Audio
RSS Feeds
Dentists around the world are using amalgams (silver fillings)
every day to fill decayed teeth, despite some erroneous news reports
stating that many countries have banned the use of amalgams.
International dental experts meeting recently at the American Dental
Association (ADA) headquarters in Chicago discussed the use of amalgam
in their respective countries.
Sweden is often cited as an example of a country that has banned
amalgam, but that is not true, according to Professor Maud Bergman of
University. Professor Bergman said it is unlikely Sweden will ban the
use of amalgams in the near future. Nor do Sweden's neighbors, Norway
and Denmark ban the use of the filling material. Representatives from
Germany and the Netherlands also said amalgam is not banned in their
countries. Dr. Elmar Reich of Germany's University of Saarland said
that some limited restrictions on the use of amalgam may even be
loosened when the classification of amalgam changes in mid-1998 to a
medical device from its current designation as a therapeutic
agent. Dentists from South Africa, Australia, New Zealand, Japan and
Canada reported that amalgam is not banned in their countries either.
Although the Canadian government has recommended some restrictions on
the use of amalgam, the Canadian Dental Association (CDA) has requested
that the government provide scientific documentation to back up some of
the recommendations that the CDA is questioning.
The World Health Organization, FDI World Dental Federation and the ADA
all support the continued use of dental amalgam as a safe, durable and
cost-effective material to restore teeth based on current scientific
knowledge. There is currently no credible scientific evidence that
exposure to mercury from amalgam restorations poses a serious health
risk in humans, except for the exceedingly small number of allergic
reactions. In 150 years of use, there have been only about 100
documented cases of allergic reactions to amalgam in the dental
literature. A joint WHO/FDI meeting is scheduled in Geneva,
Switzerland, in March, 1997, to review the latest scientific evidence on
the safety of dental amalgam.
Wednesday, September 9, 2009
Prevent Periodontitis To Reduce The Risk Of Cancer
Chronic periodontitis, a form of gum disease, is an independent risk factor for head and neck squamous cell carcinoma. This suggests the need for increased efforts to prevent and treat periodontitis as a possible means to reduce the risk of this form of cancer.
"Prevent periodontitis; if you have it already, get treatment and maintain good oral hygiene," said Mine Tezal, D.D.S., Ph.D., assistant professor in the Department of Oral Diagnostic Sciences, School of Dental Medicine, University at Buffalo, and NYS Center of Excellence in Bioinformatics and Life Sciences at the University of Buffalo. She is also a research scientist in the Department of Dentistry and Maxillofacial Prosthetics at Roswell Park Cancer Institute, which is where the study was conducted.
Results of this study are published in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research.
Chronic periodontitis is characterized by progressive loss of the bone and soft tissue attachment that surround the teeth. The researchers assessed the role of chronic periodontitis on head and neck squamous cell carcinoma, as well as the individual roles on three subsites: oral cavity, oropharyngeal and laryngeal. They used radiographic measurement of bone loss to measure periodontitis among 463 patients; 207 of whom were controls.
Findings showed that chronic periodontitis might represent a clinical high-risk profile for head and neck squamous cell carcinoma. The strength of the association was greatest in the oral cavity, followed by the oropharynx and larynx, according to Tezal.
When they stratified the relationship by tobacco use, they found that the association persisted in those patients who never used tobacco. The researchers did not expect the periodontitis-head and neck squamous cell carcinoma association to be weaker in current smokers compared to former and never smokers, according to Tezal. However, this interaction, although statistically significant, was not very strong.
"Confirmatory studies with more comprehensive assessment of smoking, such as duration, quantity and patterns of use, as well as smokeless tobacco history are needed," she said.
"Our study also suggests that chronic periodontitis may be associated with poorly differentiated tumor status in the oral cavity. Continuous stimulation of cellular proliferation by chronic inflammation may be responsible for this histological type. However, grading is subjective and we only observed this association in the oral cavity. Therefore, this association may be due to chance and needs further exploration," Tezal added.
Andrew Olshan, Ph.D., said these results lend further support to the potential importance of poor oral health in this form of cancer. Olshan is professor and chair of the Department of Epidemiology at the Gillings School of Global Public Health, and professor in the Department of Otolaryngology/Head and Neck Surgery, School of Medicine, University of North Carolina at Chapel Hill.
"The study of poor oral health including the possible carcinogenic role of microorganisms is part of a rapidly growing interest in how a community of microbes that live in the various environments of the human body can affect health," Olshan said. "Although the study is comparatively small, the researchers were able to also see an association between bone loss and the risk of head and neck cancer."
"Prevent periodontitis; if you have it already, get treatment and maintain good oral hygiene," said Mine Tezal, D.D.S., Ph.D., assistant professor in the Department of Oral Diagnostic Sciences, School of Dental Medicine, University at Buffalo, and NYS Center of Excellence in Bioinformatics and Life Sciences at the University of Buffalo. She is also a research scientist in the Department of Dentistry and Maxillofacial Prosthetics at Roswell Park Cancer Institute, which is where the study was conducted.
Results of this study are published in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research.
Chronic periodontitis is characterized by progressive loss of the bone and soft tissue attachment that surround the teeth. The researchers assessed the role of chronic periodontitis on head and neck squamous cell carcinoma, as well as the individual roles on three subsites: oral cavity, oropharyngeal and laryngeal. They used radiographic measurement of bone loss to measure periodontitis among 463 patients; 207 of whom were controls.
Findings showed that chronic periodontitis might represent a clinical high-risk profile for head and neck squamous cell carcinoma. The strength of the association was greatest in the oral cavity, followed by the oropharynx and larynx, according to Tezal.
When they stratified the relationship by tobacco use, they found that the association persisted in those patients who never used tobacco. The researchers did not expect the periodontitis-head and neck squamous cell carcinoma association to be weaker in current smokers compared to former and never smokers, according to Tezal. However, this interaction, although statistically significant, was not very strong.
"Confirmatory studies with more comprehensive assessment of smoking, such as duration, quantity and patterns of use, as well as smokeless tobacco history are needed," she said.
"Our study also suggests that chronic periodontitis may be associated with poorly differentiated tumor status in the oral cavity. Continuous stimulation of cellular proliferation by chronic inflammation may be responsible for this histological type. However, grading is subjective and we only observed this association in the oral cavity. Therefore, this association may be due to chance and needs further exploration," Tezal added.
Andrew Olshan, Ph.D., said these results lend further support to the potential importance of poor oral health in this form of cancer. Olshan is professor and chair of the Department of Epidemiology at the Gillings School of Global Public Health, and professor in the Department of Otolaryngology/Head and Neck Surgery, School of Medicine, University of North Carolina at Chapel Hill.
"The study of poor oral health including the possible carcinogenic role of microorganisms is part of a rapidly growing interest in how a community of microbes that live in the various environments of the human body can affect health," Olshan said. "Although the study is comparatively small, the researchers were able to also see an association between bone loss and the risk of head and neck cancer."
Thursday, August 20, 2009
Flying by the Skin of Our Teeth
TAU says that teeth give us clues for building lighter airplanes and space vehicles
It's been a mystery: how can our teeth withstand such an enormous amount of pressure, over many years, when tooth enamel is only about as strong as glass? A new study by Prof. Herzl Chai of Tel Aviv University's School of Mechanical Engineering and his colleagues at the National Institute of Standards and Technology and George Washington University gives the answer.
The researchers applied varying degrees of mechanical pressure to hundreds of extracted teeth, and studied what occurred on the surface and deep inside them. The study, published in the May 5, 2009, issue of the Proceedings of the National Academy of Science, shows that it is the highly-sophisticated structure of our teeth that keeps them in one piece — and that structure holds promising clues for aerospace engineers as they build the aircraft and space vehicles of the future.
"Teeth are made from an extremely sophisticated composite material which reacts in an extraordinary way under pressure," says Prof. Chai. "Teeth exhibit graded mechanical properties and a cathedral-like geometry, and over time they develop a network of micro-cracks which help diffuse stress. This, and the tooth's built-in ability to heal the micro-cracks over time, prevents it from fracturing into large pieces when we eat hard food, like nuts."
News the aviation industry can bite into
The automotive and aviation industries already use sophisticated materials to prevent break-up on impact. For example, airplane bodies are made from composite materials — layers of glass or carbon fibers — held together by a brittle matrix.
In teeth, though, fibers aren't arranged in a grid, but are "wavy" in structure. There are hierarchies of fibers and matrices arranged in several layers, unlike the single-thickness layers used in aircrafts. Under mechanical pressure, this architecture presents no clear path for the release of stress. Therefore, "tufts" — built-in micro cracks — absorb pressure in unison to prevent splits and major fractures. As Prof. Chai puts it, tooth fractures "have a hard time deciding which way to go," making the tooth more resistant to cracking apart. Harnessing this property could lead to a new generation of much stronger composites for planes.
Prof. Chai, himself an aerospace engineer, suggests that if engineers can incorporate tooth enamel's wavy hierarchy, micro-cracking mechanism, and capacity to heal, lighter and stronger aircraft and space vehicles can be developed. And while creating a self-healing airplane is far in the future, this significant research on the composite structure of teeth can already begin to inspire aerospace engineers — and, of course, dentists.
Creating a super-smile
Dental specialists looking for new ways to engineer that picture-perfect Hollywood smile can use Dr. Chai's basic research to help invent stronger crowns, better able to withstand oral wear-and-tear. "They can create smart materials that mimic the properties found in real teeth," he says.
In natural teeth, there may not be any way to speed up the self-healing ability of tooth enamel, which the Tel Aviv University research found is accomplished by a glue-like substance that fills in micro-cracks over time. But fluoride treatments and healthy brushing habits can help to fill in the tiny cracks and keep teeth strong.
It's been a mystery: how can our teeth withstand such an enormous amount of pressure, over many years, when tooth enamel is only about as strong as glass? A new study by Prof. Herzl Chai of Tel Aviv University's School of Mechanical Engineering and his colleagues at the National Institute of Standards and Technology and George Washington University gives the answer.
The researchers applied varying degrees of mechanical pressure to hundreds of extracted teeth, and studied what occurred on the surface and deep inside them. The study, published in the May 5, 2009, issue of the Proceedings of the National Academy of Science, shows that it is the highly-sophisticated structure of our teeth that keeps them in one piece — and that structure holds promising clues for aerospace engineers as they build the aircraft and space vehicles of the future.
"Teeth are made from an extremely sophisticated composite material which reacts in an extraordinary way under pressure," says Prof. Chai. "Teeth exhibit graded mechanical properties and a cathedral-like geometry, and over time they develop a network of micro-cracks which help diffuse stress. This, and the tooth's built-in ability to heal the micro-cracks over time, prevents it from fracturing into large pieces when we eat hard food, like nuts."
News the aviation industry can bite into
The automotive and aviation industries already use sophisticated materials to prevent break-up on impact. For example, airplane bodies are made from composite materials — layers of glass or carbon fibers — held together by a brittle matrix.
In teeth, though, fibers aren't arranged in a grid, but are "wavy" in structure. There are hierarchies of fibers and matrices arranged in several layers, unlike the single-thickness layers used in aircrafts. Under mechanical pressure, this architecture presents no clear path for the release of stress. Therefore, "tufts" — built-in micro cracks — absorb pressure in unison to prevent splits and major fractures. As Prof. Chai puts it, tooth fractures "have a hard time deciding which way to go," making the tooth more resistant to cracking apart. Harnessing this property could lead to a new generation of much stronger composites for planes.
Prof. Chai, himself an aerospace engineer, suggests that if engineers can incorporate tooth enamel's wavy hierarchy, micro-cracking mechanism, and capacity to heal, lighter and stronger aircraft and space vehicles can be developed. And while creating a self-healing airplane is far in the future, this significant research on the composite structure of teeth can already begin to inspire aerospace engineers — and, of course, dentists.
Creating a super-smile
Dental specialists looking for new ways to engineer that picture-perfect Hollywood smile can use Dr. Chai's basic research to help invent stronger crowns, better able to withstand oral wear-and-tear. "They can create smart materials that mimic the properties found in real teeth," he says.
In natural teeth, there may not be any way to speed up the self-healing ability of tooth enamel, which the Tel Aviv University research found is accomplished by a glue-like substance that fills in micro-cracks over time. But fluoride treatments and healthy brushing habits can help to fill in the tiny cracks and keep teeth strong.
Tuesday, August 18, 2009
Clinically assess condition of tooth enamel using lasers
A group of researchers in Australia and Taiwan has developed a new way to analyze the health of human teeth using lasers. As described in the latest issue of Optics Express, the Optical Society's (OSA) open-access journal, by measuring how the surface of a tooth responds to laser-generated ultrasound, they can evaluate the mineral content of tooth enamel -- the semi-translucent outer layer of a tooth that protects the underlying dentin.
This is the first time anyone has been able to non-destructively measure the elasticity of human teeth, creating a method that can be used to assess oral health and predict emerging dental problems, such as tooth decay and cavities.
"The ultimate goal is to come up with a quick, efficient, cost-effective, and non-destructive way to evaluate the mineralization of human dental enamel," says David Hsiao-Chuan Wang, a graduate student at the University of Sydney in Australia and first author on the paper in Optics Express. Wang and his advisor Simon Fleming, a physics professor at the University of Sydney's Institute of Photonics and Optical Science, collaborated on the study with dental researchers at the University of Sydney and ultrasonic evaluation researchers at National Cheng Kung University in Tainan City, Taiwan.
Stronger than bone, enamel is the hardest and the most mineralized substance of the human body -- one of the reasons why human teeth can survive for centuries after a person has died. It envelops teeth in a protective layer that shields the underlying dentin from decay.
Throughout a person's lifetime, enamel constantly undergoes a cycle of mineral loss and restoration, in which healthy teeth maintain a high mineral content. If the balance between mineral loss and gain is lost, however, teeth can develop areas of softened enamel -- known as carious lesions -- which are precursors to cavities and permanently damaged teeth.
Enamel demineralization is caused by bad oral hygiene. Not brushing, for instance, can lead to the build-up of dental plaques, and bacteria in these plaques will absorb sugars and other carbohydrates a person chews and produce acids that will dissolve the minerals in tooth enamel.
Quantifying the mineral content of tooth enamel can help dentists determine the location and the severity of developing dental lesions. Existing methods for evaluating enamel are limited, however. Dentists can visually assess the teeth, but dental lesions can be hard to spot in certain parts of the mouth because they are obscured by dental plaque, saliva, or the structure of a tooth itself. Dentists can use sharp instruments to probe the enamel, but this can be destructive to the teeth and gums. X-ray scans can reveal dental lesions, but they give no information on the level of mineralization.
For research purposes, "nano-indentation" is commonly used for gaining information on the elasticity of tooth enamel -- a measure of its mineral content -- but nano-indentation destroys the measured regions of the enamel in the process and is only used to look at extracted teeth.
What Wang, Fleming, and their colleagues wanted to do was to develop a clinical method that would give as much information as nano-indentation and could be used to assess tooth enamel in actual patients while being completely non-destructive. So they developed a way to measure the elasticity of tooth enamel by adapting laser ultrasonic surface wave velocity dispersion, a method similar to what industrial engineers use to evaluate the integrity of thin films and metals.
The method uses short duration laser pulses to excite ultrasonic waves that propagate along the surface and penetrate only a small distance into a tooth. The velocity of these waves is influenced by the elastic properties of the enamel on a tooth, and by detecting the ultrasonic waves with fiber optics at various points, they can determine the enamel's elasticity, which is directly related to its mineralization.
In their Optics Express article, Wang, Fleming, and their colleagues showed that they could use this technique on extracted human teeth. They have not yet tested the technique on a living person's teeth, and it will likely take several years before any eventual device is ready for use in the dentist's office.
This is the first time anyone has been able to non-destructively measure the elasticity of human teeth, creating a method that can be used to assess oral health and predict emerging dental problems, such as tooth decay and cavities.
"The ultimate goal is to come up with a quick, efficient, cost-effective, and non-destructive way to evaluate the mineralization of human dental enamel," says David Hsiao-Chuan Wang, a graduate student at the University of Sydney in Australia and first author on the paper in Optics Express. Wang and his advisor Simon Fleming, a physics professor at the University of Sydney's Institute of Photonics and Optical Science, collaborated on the study with dental researchers at the University of Sydney and ultrasonic evaluation researchers at National Cheng Kung University in Tainan City, Taiwan.
Stronger than bone, enamel is the hardest and the most mineralized substance of the human body -- one of the reasons why human teeth can survive for centuries after a person has died. It envelops teeth in a protective layer that shields the underlying dentin from decay.
Throughout a person's lifetime, enamel constantly undergoes a cycle of mineral loss and restoration, in which healthy teeth maintain a high mineral content. If the balance between mineral loss and gain is lost, however, teeth can develop areas of softened enamel -- known as carious lesions -- which are precursors to cavities and permanently damaged teeth.
Enamel demineralization is caused by bad oral hygiene. Not brushing, for instance, can lead to the build-up of dental plaques, and bacteria in these plaques will absorb sugars and other carbohydrates a person chews and produce acids that will dissolve the minerals in tooth enamel.
Quantifying the mineral content of tooth enamel can help dentists determine the location and the severity of developing dental lesions. Existing methods for evaluating enamel are limited, however. Dentists can visually assess the teeth, but dental lesions can be hard to spot in certain parts of the mouth because they are obscured by dental plaque, saliva, or the structure of a tooth itself. Dentists can use sharp instruments to probe the enamel, but this can be destructive to the teeth and gums. X-ray scans can reveal dental lesions, but they give no information on the level of mineralization.
For research purposes, "nano-indentation" is commonly used for gaining information on the elasticity of tooth enamel -- a measure of its mineral content -- but nano-indentation destroys the measured regions of the enamel in the process and is only used to look at extracted teeth.
What Wang, Fleming, and their colleagues wanted to do was to develop a clinical method that would give as much information as nano-indentation and could be used to assess tooth enamel in actual patients while being completely non-destructive. So they developed a way to measure the elasticity of tooth enamel by adapting laser ultrasonic surface wave velocity dispersion, a method similar to what industrial engineers use to evaluate the integrity of thin films and metals.
The method uses short duration laser pulses to excite ultrasonic waves that propagate along the surface and penetrate only a small distance into a tooth. The velocity of these waves is influenced by the elastic properties of the enamel on a tooth, and by detecting the ultrasonic waves with fiber optics at various points, they can determine the enamel's elasticity, which is directly related to its mineralization.
In their Optics Express article, Wang, Fleming, and their colleagues showed that they could use this technique on extracted human teeth. They have not yet tested the technique on a living person's teeth, and it will likely take several years before any eventual device is ready for use in the dentist's office.
Friday, July 31, 2009
FDA Dental Mercury Report
Mercury Released By Dental Amalgam Fillings Are Not High Enough To Cause Harm, FDA Finds
The U.S. Food and Drug Administration today issued a final regulation classifying dental amalgam and its component parts – elemental mercury and a powder alloy—used in dental fillings. While elemental mercury has been associated with adverse health effects at high exposures, the levels released by dental amalgam fillings are not high enough to cause harm in patients.
The regulation classifies dental amalgam into Class II (moderate risk). By classifying a device into Class II, the FDA can impose special controls (in addition to general controls such as good manufacturing practices that apply to all medical devices regardless of risk) to provide reasonable assurance of the safety and effectiveness of the device.
The special controls that the FDA is imposing on dental amalgam are contained in a guidance document that contains, among other things, recommendations on performance testing, device composition, and labeling statements.
Specifically, the FDA recommended that the product labeling include:
* A warning against the use of dental amalgam in patients with mercury allergy;
* A warning that dental professionals use adequate ventilation when handling dental amalgam;
* A statement discussing the scientific evidence on the benefits and risk of dental amalgam, including the risks of inhaled mercury vapor. The statement will help dentists and patients make informed decisions about the use of dental amalgam.
Dental amalgam is a “pre-amendment device,” which means that it was in use prior to May 28, 1976, when the FDA was given broad authority to regulate medical devices. That law required the FDA to issue regulations classifying pre-amendment devices according to their risk into class I, II, or III. Although the FDA previously had classified the two separate parts of amalgam – elemental mercury and the metal powder alloy – it had not issued a separate regulation classifying the combination of the two, dental amalgam. During this time, however, dental amalgam has been subject to all applicable provisions of the law.
Today’s regulation also reclassifies the mercury component of dental amalgam from Class I (low risk) to Class II (moderate risk).
Over the past six years, the FDA has taken several steps to assure that the classification of dental amalgam is supported by strong science.
In 2002, the agency issued a proposed rule to classify dental amalgam and identify any special controls necessary for its safe and effective use.
Due to a high number of comments on that rule, the agency held an advisory committee meeting in 2006, inviting dental and neurology experts to review existing scientific data on dental amalgam, especially with regard to its toxicity in pregnant women and children.
The agency drafted a review of recent and relevant peer-reviewed scientific literature on exposure to dental amalgam mercury. The advisory committee asked that the agency conduct an even deeper review of the scientific literature on this topic. In all, the agency considered some 200 scientific studies.
On April 28, 2008, the FDA reopened the comment period on the 2002 proposed classification in order to elicit the most up-to-date comments and information related to classification of dental amalgam. Today’s rule reflects the years of agency review on this topic.
FDA’s Web site on dental amalgam.
The U.S. Food and Drug Administration today issued a final regulation classifying dental amalgam and its component parts – elemental mercury and a powder alloy—used in dental fillings. While elemental mercury has been associated with adverse health effects at high exposures, the levels released by dental amalgam fillings are not high enough to cause harm in patients.
The regulation classifies dental amalgam into Class II (moderate risk). By classifying a device into Class II, the FDA can impose special controls (in addition to general controls such as good manufacturing practices that apply to all medical devices regardless of risk) to provide reasonable assurance of the safety and effectiveness of the device.
The special controls that the FDA is imposing on dental amalgam are contained in a guidance document that contains, among other things, recommendations on performance testing, device composition, and labeling statements.
Specifically, the FDA recommended that the product labeling include:
* A warning against the use of dental amalgam in patients with mercury allergy;
* A warning that dental professionals use adequate ventilation when handling dental amalgam;
* A statement discussing the scientific evidence on the benefits and risk of dental amalgam, including the risks of inhaled mercury vapor. The statement will help dentists and patients make informed decisions about the use of dental amalgam.
Dental amalgam is a “pre-amendment device,” which means that it was in use prior to May 28, 1976, when the FDA was given broad authority to regulate medical devices. That law required the FDA to issue regulations classifying pre-amendment devices according to their risk into class I, II, or III. Although the FDA previously had classified the two separate parts of amalgam – elemental mercury and the metal powder alloy – it had not issued a separate regulation classifying the combination of the two, dental amalgam. During this time, however, dental amalgam has been subject to all applicable provisions of the law.
Today’s regulation also reclassifies the mercury component of dental amalgam from Class I (low risk) to Class II (moderate risk).
Over the past six years, the FDA has taken several steps to assure that the classification of dental amalgam is supported by strong science.
In 2002, the agency issued a proposed rule to classify dental amalgam and identify any special controls necessary for its safe and effective use.
Due to a high number of comments on that rule, the agency held an advisory committee meeting in 2006, inviting dental and neurology experts to review existing scientific data on dental amalgam, especially with regard to its toxicity in pregnant women and children.
The agency drafted a review of recent and relevant peer-reviewed scientific literature on exposure to dental amalgam mercury. The advisory committee asked that the agency conduct an even deeper review of the scientific literature on this topic. In all, the agency considered some 200 scientific studies.
On April 28, 2008, the FDA reopened the comment period on the 2002 proposed classification in order to elicit the most up-to-date comments and information related to classification of dental amalgam. Today’s rule reflects the years of agency review on this topic.
FDA’s Web site on dental amalgam.
Wednesday, July 29, 2009
Worm-like Structures Inside Dissected Molar
Micro-images Of Strange, Worm-like Structures Uncovered Inside Dissected Molar
New, micro-images of strange, worm-like structures uncovered inside a dissected molar might have been held in ancient times as proof that gnawing tooth worms were the cause of tooth decay, a theory widely believed in many cultures before modern times.
The structures are not worms, but what they are is still in question.
Studies by University of Maryland Dental School researchers’ presented today at the annual meeting of the Microscopy Society of America in Richmond revealed cylindrical objects extending or ‘growing’ out of the natural pores or tubules of teeth. Inside a human tooth, more than 50,000 such tubules per square millimeter act as channels running from the nerve up through the tooth. They are associated with transporting hot or cold sensitivity to the tooth nerve. [A human hair by comparison is 40 micrometers wide.]
For years, scientists have debated the exact nature of the worm-like structures, which were photographed in clear detail by Ru-Ching Hsia, director of the electron microscope core facility at the School.
Dentists’ explanations vary on nature and origin of the structures. “Most say ‘I have no idea.’ Others say they are made of bacteria, or minerals, or hyphal branches of yeast cells (C. albicans) which have infected the tooth structure, or perhaps they are a cellular process of the dentinal tubules,” said co-presenter Gary Hack, DDS, associate professor in the Dental School. For the sake of humoring his students, Hack says, “I call them tooth worms and I’m sticking to it.”
The aim of the Maryland study was to investigate the structures with scanning electron imagery and different specimen preparation techniques. The researchers’ observations raised new questions in the controversy over nature of the strange structures. For example, they found two of the cylinder structures within a single tubule, a discovery that challenges the hypothesis that the structures are cellular extensions.
The tubules ranged from 2.6 to 3.5 micrometers in diameter and the worm-like structures were smaller in the tubules in which they appeared. The structures were as long as 9 micrometers, extending out of the tubule opening. Whereas the majority of the structures appear to be hollow and devoid of any content, a number of these structures appear to be solid. The majority of the structures have a diameter ranging from 1.5 to 1.9 micrometers. Some of the structures appeared to be solid. Other pictures revealed a comparatively thin, hollow structure emerging from a single dentinal tubule.
Across the ages, both advanced civilizations and as far back as the Roman Empire and the Middle Ages believed in the tooth worm, with physicians prescribing various herbs, rinsings and fumigations.
Tuesday, July 14, 2009
Oral health care within health care reform
For largely historical reasons, the dental profession has evolved parallel to, but separately from, the medical profession. Medicine and dentistry have different educational, health care delivery and payment systems. But the mouth and body are not separate biologic systems. Recent dental research findings are uncovering the full extent to which oral health is linked to general health.
The two most common dental diseases, dental caries (tooth decay) and periodontal disease (gum disease) are the sequelae of microbial infections. Yet, for the more than 80 million American who have medical insurance, but no dental insurance, that infection is not covered. Further, periodontal infections result in a full body inflammatory response that may explain the association with other systemic diseases of inflammatory origin, such as cardiovascular disease.
Oral health research is the underpinning for good oral health, and has greatly affected the way oral health care is delivered. However, advances in care and treatment models have not been shared equally by all Americans, and the physical and economic burden of oral disease continues to outweigh that of other more commonly covered diseases and conditions. More than 51 million school hours and 164 million hours of work are lost each year due to dental related absences. While continued dental research is essential to managing and one day eliminating oral disease, putting current knowledge into practice now is critical to improving oral health for all Americans.
In 2000, the U.S. Surgeon General called the nation's attention to the importance of oral health with the landmark report "Oral Health in America." The report recognized the associations between oral health and general health and called upon policy makers to "build an effective health infrastructure that meets the oral health needs of all Americans and integrates oral health effectively into overall health." Nearly a decade later, it's time to respond to the Surgeon General.
The American Association for Dental Research has made the following policy recommendations:
Provide accessible and affordable oral health care to facilitate the application of dental research findings and to improve the oral health of all Americans
As research has shown the interconnectedness between oral health and overall health, include the prevention, diagnosis, and treatment of oral diseases in health care reform.
Continue a sustained investment in biomedical research, including in the NIH National Institute of Dental and Craniofacial Research to further reduce the burden of oral diseases for all Americans.
The entire Statement is available here.
The two most common dental diseases, dental caries (tooth decay) and periodontal disease (gum disease) are the sequelae of microbial infections. Yet, for the more than 80 million American who have medical insurance, but no dental insurance, that infection is not covered. Further, periodontal infections result in a full body inflammatory response that may explain the association with other systemic diseases of inflammatory origin, such as cardiovascular disease.
Oral health research is the underpinning for good oral health, and has greatly affected the way oral health care is delivered. However, advances in care and treatment models have not been shared equally by all Americans, and the physical and economic burden of oral disease continues to outweigh that of other more commonly covered diseases and conditions. More than 51 million school hours and 164 million hours of work are lost each year due to dental related absences. While continued dental research is essential to managing and one day eliminating oral disease, putting current knowledge into practice now is critical to improving oral health for all Americans.
In 2000, the U.S. Surgeon General called the nation's attention to the importance of oral health with the landmark report "Oral Health in America." The report recognized the associations between oral health and general health and called upon policy makers to "build an effective health infrastructure that meets the oral health needs of all Americans and integrates oral health effectively into overall health." Nearly a decade later, it's time to respond to the Surgeon General.
The American Association for Dental Research has made the following policy recommendations:
Provide accessible and affordable oral health care to facilitate the application of dental research findings and to improve the oral health of all Americans
As research has shown the interconnectedness between oral health and overall health, include the prevention, diagnosis, and treatment of oral diseases in health care reform.
Continue a sustained investment in biomedical research, including in the NIH National Institute of Dental and Craniofacial Research to further reduce the burden of oral diseases for all Americans.
The entire Statement is available here.
Saturday, July 11, 2009
Diets bad for the teeth are also bad for the body
Beyond the immediate distress, dental pain may portend future medical problems
Dental disease may be a wake-up call that your diet is harming your body.
"The five-alarm fire bell of a tooth ache is difficult to ignore," says Dr. Philippe P. Hujoel, professor of dental public health sciences at the University of Washington (UW) School of Dentistry in Seattle. Beyond the immediate distress, dental pain may portend future medical problems. It may be a warning that the high-glycemic diet that led to dental problems in the short term may, in the long term, lead to potentially serious chronic diseases.
Hujoel reviewed the relationships between diet, dental disease, and chronic systemic illness in a report published July 1 in the Journal of Dental Research. He weighed two contradictory viewpoints on the role of dietary carbohydrates in health and disease. The debate surrounds fermentable carbohydates: foods that turn into simple sugars in the mouth. Fermentable carbohydrates are not just sweets like cookies, doughnuts, cake and candy. They also include bananas and several tropical fruits, sticky fruits like raisins and other dried fruits, and starchy foods like potatoes, refined wheat flour, yams, rice, pasta, pretzels, bread, and corn.
One viewpoint is that certain fermentable carbohydrates are beneficial to general health and that the harmful dental consequences of such a diet should be managed by the tools found in the oral hygiene section of drugstores. A contrasting viewpoint suggests that fermentable carbohydrates are bad for both dental and general health, and that both dental and general health need to be maintained by restricting fermentable carbohydrates.
The differing perspectives on the perceived role of dietary carbohydrates have resulted in opposing approaches to dental disease prevention, Hujoel notes, and have prompted debates in interpreting the link between dental diseases and such systemic diseases as obesity, diabetes, and some forms of cancer.
Over the past twenty years or so, Hujoel says, people have been advised to make fermentable dietary carbohydrates the foundation of their diet. Fats were considered the evil food. A high-carbohydrate diet was assumed to prevent a number of systemic chronic diseases. Unfortunately, such a diet - allegedly good for systemic health - was bad for dental health. As a result, cavities or gingival bleeding from fermentable carbohydrates could be avoided only – and not always successfully, as Hujoel points out -- by conscientious brushing, fluorides, and other types of dental preventive measures. When these measures are not successful, people end up with cavities and gum disease.
Hujoel observed that the dental harms of fermentable carbohydrates have been recognized by what looks like every major health organization. Even those fermentable carbohydrates assumed to be good for systemic health break down into simple sugars in the mouth and promote tooth decay. All fermentable carbohydrates have the potential to induce dental decay, Hujoel notes.
But what if fermentable carbohydrates are also bad for systemic health? Hujoel asks. What if dietary guidelines would start incorporating the slew of clinical trial results suggesting that a diet low in fermentable carbohydrates improves cardiovascular markers of disease and decreases body fat? Such a change in perspective on fermentable carbohydrates, and by extension, on people's diets, could have a significant impact on the dental profession, as a diet higher in fat and protein does not cause dental diseases, he notes. Dentists would no longer be pressed to recommend to patients diets that are bad for teeth or remain mum when it comes to dietary advice. Dentists often have been reluctant, Hujoel says, to challenge the prevailing thinking on nutrition. Advising patients to reduce the amount or frequency of fermentable carbohydrate consumption is difficult when official guidelines suggested the opposite.
The close correlation between the biological mechanisms that cause dental decay and the factors responsible for high average levels of glucose in the blood is intriguing. Hujoel explains that eating sugar or fermentable carbohydrates drops the acidity levels of dental plaque and is considered an initiating cause of dental decay.
"Eating these same foods, he says, is also associated with spikes in blood sugar levels. There is fascinating evidence that suggests that the higher the glycemic level of a food, the more it will drop the acidity of dental plaque, and the higher it will raise blood sugar. So, possibly, dental decay may really be a marker for the chronic high-glycemic diets that lead to both dental decay and chronic systemic diseases. This puts a whole new light on studies that have linked dental diseases to such diverse illnesses as Alzheimer's disease and pancreatic cancer."
The correlations between dental diseases and systemic disease, he adds, provide indirect support for those researchers who have suggested that Alzheimer's disease and pancreatic cancer are due to an abnormal blood glucose metabolism.
The hypotheses on dental diseases as a marker for the diseases of civilization were postulated back in the mid-20th century by two physicians: Thomas Cleave and John Yudkin. Tragically, their work, although supported by epidemiological evidence, became largely forgotten, Hujoel notes. This is unfortunate, he adds, because dental diseases really may be the most noticeable and rapid warning sign to an individual that something is going awry with his or her diet.
"Dental problems from poor dietary habits appear in a few weeks to a few years," Hujoel explains. "Dental improvement can be rapid when habits are corrected. For example, reducing sugar intake can often improve gingivitis scores (a measurement of gum disease) in a couple of weeks. Dental disease reveals very early on that eating habits are putting a person at risk for systemic disease. Because chronic medical disease takes decades to become severe enough to be detected in screening tests, dental diseases may provide plenty of lead-time to change harmful eating habits and thereby decrease the risk of developing the other diseases of civilization."
In planning a daily or weekly menu, Hujoel suggests: "What's good for your oral health looks increasingly likely to also benefit your overall health."
Dental disease may be a wake-up call that your diet is harming your body.
"The five-alarm fire bell of a tooth ache is difficult to ignore," says Dr. Philippe P. Hujoel, professor of dental public health sciences at the University of Washington (UW) School of Dentistry in Seattle. Beyond the immediate distress, dental pain may portend future medical problems. It may be a warning that the high-glycemic diet that led to dental problems in the short term may, in the long term, lead to potentially serious chronic diseases.
Hujoel reviewed the relationships between diet, dental disease, and chronic systemic illness in a report published July 1 in the Journal of Dental Research. He weighed two contradictory viewpoints on the role of dietary carbohydrates in health and disease. The debate surrounds fermentable carbohydates: foods that turn into simple sugars in the mouth. Fermentable carbohydrates are not just sweets like cookies, doughnuts, cake and candy. They also include bananas and several tropical fruits, sticky fruits like raisins and other dried fruits, and starchy foods like potatoes, refined wheat flour, yams, rice, pasta, pretzels, bread, and corn.
One viewpoint is that certain fermentable carbohydrates are beneficial to general health and that the harmful dental consequences of such a diet should be managed by the tools found in the oral hygiene section of drugstores. A contrasting viewpoint suggests that fermentable carbohydrates are bad for both dental and general health, and that both dental and general health need to be maintained by restricting fermentable carbohydrates.
The differing perspectives on the perceived role of dietary carbohydrates have resulted in opposing approaches to dental disease prevention, Hujoel notes, and have prompted debates in interpreting the link between dental diseases and such systemic diseases as obesity, diabetes, and some forms of cancer.
Over the past twenty years or so, Hujoel says, people have been advised to make fermentable dietary carbohydrates the foundation of their diet. Fats were considered the evil food. A high-carbohydrate diet was assumed to prevent a number of systemic chronic diseases. Unfortunately, such a diet - allegedly good for systemic health - was bad for dental health. As a result, cavities or gingival bleeding from fermentable carbohydrates could be avoided only – and not always successfully, as Hujoel points out -- by conscientious brushing, fluorides, and other types of dental preventive measures. When these measures are not successful, people end up with cavities and gum disease.
Hujoel observed that the dental harms of fermentable carbohydrates have been recognized by what looks like every major health organization. Even those fermentable carbohydrates assumed to be good for systemic health break down into simple sugars in the mouth and promote tooth decay. All fermentable carbohydrates have the potential to induce dental decay, Hujoel notes.
But what if fermentable carbohydrates are also bad for systemic health? Hujoel asks. What if dietary guidelines would start incorporating the slew of clinical trial results suggesting that a diet low in fermentable carbohydrates improves cardiovascular markers of disease and decreases body fat? Such a change in perspective on fermentable carbohydrates, and by extension, on people's diets, could have a significant impact on the dental profession, as a diet higher in fat and protein does not cause dental diseases, he notes. Dentists would no longer be pressed to recommend to patients diets that are bad for teeth or remain mum when it comes to dietary advice. Dentists often have been reluctant, Hujoel says, to challenge the prevailing thinking on nutrition. Advising patients to reduce the amount or frequency of fermentable carbohydrate consumption is difficult when official guidelines suggested the opposite.
The close correlation between the biological mechanisms that cause dental decay and the factors responsible for high average levels of glucose in the blood is intriguing. Hujoel explains that eating sugar or fermentable carbohydrates drops the acidity levels of dental plaque and is considered an initiating cause of dental decay.
"Eating these same foods, he says, is also associated with spikes in blood sugar levels. There is fascinating evidence that suggests that the higher the glycemic level of a food, the more it will drop the acidity of dental plaque, and the higher it will raise blood sugar. So, possibly, dental decay may really be a marker for the chronic high-glycemic diets that lead to both dental decay and chronic systemic diseases. This puts a whole new light on studies that have linked dental diseases to such diverse illnesses as Alzheimer's disease and pancreatic cancer."
The correlations between dental diseases and systemic disease, he adds, provide indirect support for those researchers who have suggested that Alzheimer's disease and pancreatic cancer are due to an abnormal blood glucose metabolism.
The hypotheses on dental diseases as a marker for the diseases of civilization were postulated back in the mid-20th century by two physicians: Thomas Cleave and John Yudkin. Tragically, their work, although supported by epidemiological evidence, became largely forgotten, Hujoel notes. This is unfortunate, he adds, because dental diseases really may be the most noticeable and rapid warning sign to an individual that something is going awry with his or her diet.
"Dental problems from poor dietary habits appear in a few weeks to a few years," Hujoel explains. "Dental improvement can be rapid when habits are corrected. For example, reducing sugar intake can often improve gingivitis scores (a measurement of gum disease) in a couple of weeks. Dental disease reveals very early on that eating habits are putting a person at risk for systemic disease. Because chronic medical disease takes decades to become severe enough to be detected in screening tests, dental diseases may provide plenty of lead-time to change harmful eating habits and thereby decrease the risk of developing the other diseases of civilization."
In planning a daily or weekly menu, Hujoel suggests: "What's good for your oral health looks increasingly likely to also benefit your overall health."
Wednesday, July 8, 2009
Link between obesity and oral bacterial infection?
Forsyth scientists suggest linkages between obesity and oral bacterial infection
A scientific team from The Forsyth Institute has discovered new links between certain oral bacteria and obesity. In a recent study, the researchers demonstrated that the salivary bacterial composition of overweight women differs from non-overweight women. This preliminary work may provide clues to interactions between oral bacteria and the pathology of obesity. This research may help investigators learn new avenues for fighting the obesity epidemic.
This work will be published in the Journal of Dental Research, and is available online today at http://jdr.sagepub.com/cgi/content/full/88/6/519."There has been a world-wide explosion of obesity, with many contributing factors," said Dr. J. Max Goodson, senior author of the study. "However, the inflammatory nature of the disease is also recognized. This led me to question potential unknown contributing causes of obesity. Could it be an epidemic involving an infectious agent?" "It is exciting to image the possibilities if oral bacteria are contributing to some types of obesity," added Goodson.
Summary of Study
In order to measure the salivary bacterial populations of overweight women, samples were collected from 313 women with a body mass index between 27 and 32 (classifying them as overweight). Using DNA analysis, the researchers measured the bacterial populations of this group and compared it with historical data from 232 individuals that were not overweight. Significant differences in seven of the 40 species studied occurred in the salivary bacteria of subjects in the overweight group. In addition, more than 98 percent of the overweight women could be identified by the presence of a single bacterial species, called Selenomanas noxia, at levels greater than 1.05 percent of the total salivary bacteria. These data suggest that the composition of salivary bacteria changes in overweight women. It seems likely that these bacterial species could serve as indicators of a developing overweight condition and possibly be related to the underlying causation.
Dr. Goodson noted that the reasons for a relationship between obesity and oral bacteria are likely complex. The observed relationship may be circumstantial as being related to diet or opportunistic due to metabolic changes. In the next phase of this research, Dr. Goodson plans to further examine this relationship by initially conducting a controlled cohort study to see if this initial observation can be reproduced. In addition, he hopes to conduct longitudinal studies in children to see if oral infection relates to weight gain. Ultimately, the development of strategies to eliminate specific oral bacteria would be required to provide definitive evidence that certain oral bacteria may be responsible for weight gain.
A scientific team from The Forsyth Institute has discovered new links between certain oral bacteria and obesity. In a recent study, the researchers demonstrated that the salivary bacterial composition of overweight women differs from non-overweight women. This preliminary work may provide clues to interactions between oral bacteria and the pathology of obesity. This research may help investigators learn new avenues for fighting the obesity epidemic.
This work will be published in the Journal of Dental Research, and is available online today at http://jdr.sagepub.com/cgi/content/full/88/6/519."There has been a world-wide explosion of obesity, with many contributing factors," said Dr. J. Max Goodson, senior author of the study. "However, the inflammatory nature of the disease is also recognized. This led me to question potential unknown contributing causes of obesity. Could it be an epidemic involving an infectious agent?" "It is exciting to image the possibilities if oral bacteria are contributing to some types of obesity," added Goodson.
Summary of Study
In order to measure the salivary bacterial populations of overweight women, samples were collected from 313 women with a body mass index between 27 and 32 (classifying them as overweight). Using DNA analysis, the researchers measured the bacterial populations of this group and compared it with historical data from 232 individuals that were not overweight. Significant differences in seven of the 40 species studied occurred in the salivary bacteria of subjects in the overweight group. In addition, more than 98 percent of the overweight women could be identified by the presence of a single bacterial species, called Selenomanas noxia, at levels greater than 1.05 percent of the total salivary bacteria. These data suggest that the composition of salivary bacteria changes in overweight women. It seems likely that these bacterial species could serve as indicators of a developing overweight condition and possibly be related to the underlying causation.
Dr. Goodson noted that the reasons for a relationship between obesity and oral bacteria are likely complex. The observed relationship may be circumstantial as being related to diet or opportunistic due to metabolic changes. In the next phase of this research, Dr. Goodson plans to further examine this relationship by initially conducting a controlled cohort study to see if this initial observation can be reproduced. In addition, he hopes to conduct longitudinal studies in children to see if oral infection relates to weight gain. Ultimately, the development of strategies to eliminate specific oral bacteria would be required to provide definitive evidence that certain oral bacteria may be responsible for weight gain.
Monday, July 6, 2009
Sugar substitute prevents early-childhood cavities
Children given an oral syrup containing the naturally occurring sweetener xylitol may be less likely to develop decay in their baby teeth, according to a report in the July issue of Archives of Pediatrics & Adolescent Medicine, one of the JAMA/Archives journals.
Early childhood caries (cavities), also called baby bottle tooth decay or nursing caries, continue to increase in prevalence, according to background information in the article. "Poor children experience rates twice as high as those of their more affluent peers, and their disease is more likely to be untreated," the authors write. "Poor oral health affects diet and nutrition and significantly diminishes quality of life. However, tooth decay is a disease that is largely preventable."
Xylitol, approved in the United States for use in food since 1963, has been shown to effectively prevent tooth decay by acting as an antibacterial agent against organisms that cause cavities. These previous investigations have primarily involved chewing gum or lozenges used in school-age children with permanent teeth. Peter Milgrom, D.D.S., of the University of Washington, Seattle, and colleagues evaluated the effectiveness of applying oral syrup containing xylitol among 94 children age 9 to 15 months in the Republic of the Marshall Islands, where early childhood tooth decay is a serious health care problem.
Two active treatment groups received 8 grams per day of xylitol syrup divided into two (33 children) or three (32 children) doses per day. A third, control group of 29 children received a small amount (a single 2.67-gram dose) of xylitol syrup per day because the internal review committee appointed by the secretary of health of the Republic of the Marshall Islands did not permit the use of a placebo.
After an average of 10.5 months, eight of 33 children (24.2 percent) receiving two doses of xylitol per day and 13 of the 32 children (40.6 percent) receiving three doses of xylitol per day had tooth decay, compared with 15 of the 29 children (51.7 percent) in the control group. The average numbers of decayed teeth were 0.6 in the two-dose xylitol group, one in the three-dose xylitol group and 1.9 in the control group.
"Our results suggest that exposure to xylitol (8 grams per day) in a twice-daily topical oral syrup during primary tooth eruption could prevent up to 70 percent of decayed teeth," the authors write. "Dividing the 8 grams into three doses did not increase the effectiveness of the treatment. These results provide evidence for the first time (to our knowledge) that xylitol is effective for the prevention of decay in primary teeth of toddlers." More research is needed to develop vehicles and strategies for optimal public health, but in populations with high rates of tooth decay, xylitol is likely to be a cost-effective preventive measure, they conclude.
"Early childhood caries is well understood by microbiologists and research dentists—if not by the general public and their health care providers—as ordinary tooth decay run amok," writes Burton L. Edelstein, D.D.S., M.P.H., of the College of Dental Medicine, Columbia University, in an accompanying editorial.
"It most commonly manifests as extensive tooth destruction and associated pain, with or without infection, by age 22 months and sometimes much earlier," Dr. Edelstein continues. "The Centers for Disease Control and Prevention reports that more than one-quarter of all U.S. toddlers and preschoolers (28 percent) are affected."
"Findings reported herein by Milgrom and colleagues that xylitol application holds strong promise to significantly dampen early childhood caries occurrence are encouraging and suggest the addition of this approach to pharmacologic management in public health and individual care settings. Xylitol application, like fluoride varnish application, will likely become a routine element of early childhood caries control. The finding, however, that early childhood caries prevalence remained at 24 percent to 41 percent among treated children at the close of the trial in a high-caries-experience population reminds us that no single 'silver bullet' is going to solve the problem of early childhood caries."
Early childhood caries (cavities), also called baby bottle tooth decay or nursing caries, continue to increase in prevalence, according to background information in the article. "Poor children experience rates twice as high as those of their more affluent peers, and their disease is more likely to be untreated," the authors write. "Poor oral health affects diet and nutrition and significantly diminishes quality of life. However, tooth decay is a disease that is largely preventable."
Xylitol, approved in the United States for use in food since 1963, has been shown to effectively prevent tooth decay by acting as an antibacterial agent against organisms that cause cavities. These previous investigations have primarily involved chewing gum or lozenges used in school-age children with permanent teeth. Peter Milgrom, D.D.S., of the University of Washington, Seattle, and colleagues evaluated the effectiveness of applying oral syrup containing xylitol among 94 children age 9 to 15 months in the Republic of the Marshall Islands, where early childhood tooth decay is a serious health care problem.
Two active treatment groups received 8 grams per day of xylitol syrup divided into two (33 children) or three (32 children) doses per day. A third, control group of 29 children received a small amount (a single 2.67-gram dose) of xylitol syrup per day because the internal review committee appointed by the secretary of health of the Republic of the Marshall Islands did not permit the use of a placebo.
After an average of 10.5 months, eight of 33 children (24.2 percent) receiving two doses of xylitol per day and 13 of the 32 children (40.6 percent) receiving three doses of xylitol per day had tooth decay, compared with 15 of the 29 children (51.7 percent) in the control group. The average numbers of decayed teeth were 0.6 in the two-dose xylitol group, one in the three-dose xylitol group and 1.9 in the control group.
"Our results suggest that exposure to xylitol (8 grams per day) in a twice-daily topical oral syrup during primary tooth eruption could prevent up to 70 percent of decayed teeth," the authors write. "Dividing the 8 grams into three doses did not increase the effectiveness of the treatment. These results provide evidence for the first time (to our knowledge) that xylitol is effective for the prevention of decay in primary teeth of toddlers." More research is needed to develop vehicles and strategies for optimal public health, but in populations with high rates of tooth decay, xylitol is likely to be a cost-effective preventive measure, they conclude.
"Early childhood caries is well understood by microbiologists and research dentists—if not by the general public and their health care providers—as ordinary tooth decay run amok," writes Burton L. Edelstein, D.D.S., M.P.H., of the College of Dental Medicine, Columbia University, in an accompanying editorial.
"It most commonly manifests as extensive tooth destruction and associated pain, with or without infection, by age 22 months and sometimes much earlier," Dr. Edelstein continues. "The Centers for Disease Control and Prevention reports that more than one-quarter of all U.S. toddlers and preschoolers (28 percent) are affected."
"Findings reported herein by Milgrom and colleagues that xylitol application holds strong promise to significantly dampen early childhood caries occurrence are encouraging and suggest the addition of this approach to pharmacologic management in public health and individual care settings. Xylitol application, like fluoride varnish application, will likely become a routine element of early childhood caries control. The finding, however, that early childhood caries prevalence remained at 24 percent to 41 percent among treated children at the close of the trial in a high-caries-experience population reminds us that no single 'silver bullet' is going to solve the problem of early childhood caries."
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