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Printing teeth
What if, instead of waiting days or weeks for a cast to be produced and prosthetic dental implants, false teeth and replacement crowns to be made, your dentist could quickly scan your jaw and "print" your new teeth using a rapid prototyping machine known as a 3D printer?
Researchers in Iran explain how medical imaging coupled with computer-aided design could be used to create a perfect-fit blueprint for prosthetic dentistry, whether to replace diseased or broken teeth and jaw bone. The blueprint can then be fed into a so-called 3D printer to build up an exact replica using a biocompatible composite material. Such technology has been used in medical prosthetics before, but this is an early step into prosthetic dentistry using rapid prototyping.
Writing in the International Journal of Rapid Manufacturing, mechanical engineer Hossein Kheirollahi of the Imam Hossein University and colleague Farid Abbaszadeh of the Islamic Azad University, in Tehran, Iran, explain how current technology used to convert an MRI or CT scan into a prosthetic component requires milling technology. This carves out the appropriate solid shape from a block of polymer but has several disadvantages, uppermost being that it is very difficult to carve out a complex shape, such as a tooth. By contrast, rapid prototyping uses a 3D image held in a computer to control a laser that then "cures" powdered or liquid polymer. Almost any solid, porous, or complicated shape can be produced by this 3D-printing technology.
The Iranian team has now demonstrated how rapid prototyping can be used to fabricate dental objects such as implants and crowns quickly and easily even where features such as overhangs, sharp corners and undercuts are required. The team points out that the most appropriate medical imaging technology, CBCT (cone-beam computed tomography), which is lower cost and exposes the patient to a lower dose of ionizing radiation is best suited to the generation of the computer design for creating such dental objects ready for printing.
Thursday, July 14, 2011
Dentists can identify people with undiagnosed diabetes
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In a study, Identification of unrecognized diabetes and pre-diabetes in a dental setting, published in the July 2011 issue of the Journal of Dental Research, researchers at Columbia University College of Dental Medicine found that dental visits represented a chance to intervene in the diabetes epidemic by identifying individuals with diabetes or pre-diabetes who are unaware of their condition. The study sought to develop and evaluate an identification protocol for high blood sugar levels in dental patients and was supported by a research grant from Colgate-Palmolive. The authors report no potential financial or other conflicts.
"Periodontal disease is an early complication of diabetes, and about 70 percent of U.S. adults see a dentist at least once a year," says Dr. Ira Lamster, dean of the College of Dental Medicine, and senior author on the paper. "Prior research focused on identification strategies relevant to medical settings. Oral healthcare settings have not been evaluated before, nor have the contributions of oral findings ever been tested prospectively."
For this study, researchers recruited approximately 600 individuals visiting a dental clinic in Northern Manhattan who were 40-years-old or older (if non-Hispanic white) and 30-years-old or older (if Hispanic or non-white), and had never been told they have diabetes or pre-diabetes.
Approximately 530 patients with at least one additional self-reported diabetes risk factor (family history of diabetes, high cholesterol, hypertension, or overweight/obesity) received a periodontal examination and a fingerstick, point-of-care hemoglobin A1c test. In order for the investigators to assess and compare the performance of several potential identification protocols, patients returned for a fasting plasma glucose test, which indicates whether an individual has diabetes or pre-diabetes.
Researchers found that, in this at-risk dental population, a simple algorithm composed of only two dental parameters (number of missing teeth and percentage of deep periodontal pockets) was effective in identifying patients with unrecognized pre-diabetes or diabetes. The addition of the point-of-care A1c test was of significant value, further improving the performance of this algorithm.
"Early recognition of diabetes has been the focus of efforts from medical and public health colleagues for years, as early treatment of affected individuals can limit the development of many serious complications," says Dr. Evanthia Lalla, an associate professor at the College of Dental Medicine, and the lead author on the paper. "Relatively simple lifestyle changes in pre-diabetic individuals can prevent progression to frank diabetes, so identifying this group of individuals is also important," she adds. "Our findings provide a simple approach that can be easily used in all dental-care settings."
In a study, Identification of unrecognized diabetes and pre-diabetes in a dental setting, published in the July 2011 issue of the Journal of Dental Research, researchers at Columbia University College of Dental Medicine found that dental visits represented a chance to intervene in the diabetes epidemic by identifying individuals with diabetes or pre-diabetes who are unaware of their condition. The study sought to develop and evaluate an identification protocol for high blood sugar levels in dental patients and was supported by a research grant from Colgate-Palmolive. The authors report no potential financial or other conflicts.
"Periodontal disease is an early complication of diabetes, and about 70 percent of U.S. adults see a dentist at least once a year," says Dr. Ira Lamster, dean of the College of Dental Medicine, and senior author on the paper. "Prior research focused on identification strategies relevant to medical settings. Oral healthcare settings have not been evaluated before, nor have the contributions of oral findings ever been tested prospectively."
For this study, researchers recruited approximately 600 individuals visiting a dental clinic in Northern Manhattan who were 40-years-old or older (if non-Hispanic white) and 30-years-old or older (if Hispanic or non-white), and had never been told they have diabetes or pre-diabetes.
Approximately 530 patients with at least one additional self-reported diabetes risk factor (family history of diabetes, high cholesterol, hypertension, or overweight/obesity) received a periodontal examination and a fingerstick, point-of-care hemoglobin A1c test. In order for the investigators to assess and compare the performance of several potential identification protocols, patients returned for a fasting plasma glucose test, which indicates whether an individual has diabetes or pre-diabetes.
Researchers found that, in this at-risk dental population, a simple algorithm composed of only two dental parameters (number of missing teeth and percentage of deep periodontal pockets) was effective in identifying patients with unrecognized pre-diabetes or diabetes. The addition of the point-of-care A1c test was of significant value, further improving the performance of this algorithm.
"Early recognition of diabetes has been the focus of efforts from medical and public health colleagues for years, as early treatment of affected individuals can limit the development of many serious complications," says Dr. Evanthia Lalla, an associate professor at the College of Dental Medicine, and the lead author on the paper. "Relatively simple lifestyle changes in pre-diabetic individuals can prevent progression to frank diabetes, so identifying this group of individuals is also important," she adds. "Our findings provide a simple approach that can be easily used in all dental-care settings."
Tuesday, July 12, 2011
Higher Medicaid payments to dentists associated with increased rate of dental care among children
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Children and adolescents from states that had higher Medicaid payment levels to dentists between 2000 and 2008 were more likely to receive dental care, although children covered by Medicaid received dental care less often than children with private insurance, according to a study in the July 13 issue of JAMA.
According to background information in the article, more than one-third of children are covered by public health insurance, primarily Medicaid and the Children's Health Insurance Program (CHIP). Coverage of dental care for children and adolescents covered by Medicaid and CHIP is required, although states have wide latitude in setting payment rates for providers including dentists, with these rates varying greatly by state. Medicaid recipients may not be able to access dental care if dentists decline to participate in Medicaid because of low payment levels or other reasons. Little is known about the effect of state dental fees on participation of dentists in the Medicaid program.
Sandra L. Decker, Ph.D., of the Centers for Disease Control and Prevention, Hyattsville, Md., conducted a study to examine the association of state Medicaid payment rates for dental care with the receipt of dental care among children covered by Medicaid. The study included data on Medicaid dental fees in 2000 and 2008 for 42 states plus the District of Columbia, and these data were merged with data from 33,657 children and adolescents (ages 2-17 years) in the National Health Interview Survey (NHIS) for the years 2000-2001 and 2008-2009.
Of the 42 states plus the District of Columbia considered in the analyses, the 2008 Medicaid dental fees were lower than the (inflation-adjusted) 2000 fees in 23 states. Payment levels to dentists in 2008 were higher than in 2000 in 19 states plus the District of Columbia. In five states (Connecticut, Indiana, Montana, New York, and Texas) plus the District of Columbia, payments increased by at least 50 percent between 2000 and 2008.
The researchers found that the probability that a child or adolescent had seen a dentist in the past 6 months varied by insurance source. In 2008-2009, children and adolescents covered by Medicaid were less likely (55 percent) than children with private insurance (68 percent) to have seen a dentist in the past 6 months, but were more likely to have seen a dentist than children or adolescents without insurance (27 percent). According to the author's, "children were about 6 percentage points more likely to have seen a dentist in 2008-2009 than in 2000-2001. … Those covered by Medicaid or CHIP were about 13 percentage points and uninsured children were about 40 percentage points less likely than children with private insurance to have seen a dentist."
"Changes in state Medicaid dental payment fees between 2000 and 2008 were positively associated with use of dental care among children and adolescents covered by Medicaid. For example, a $10 increase in the Medicaid prophylaxis payment level (from $20 to $30) was associated with a 3.92 percentage point increase in the chance that a child or adolescent covered by Medicaid had seen a dentist," the authors write.
"As future expansions in Medicaid eligibility and insurance coverage more generally are contemplated and possibly implemented, more attention to the effects of provider payment policies on access to care, quality of care, and health outcomes may be warranted."
Children and adolescents from states that had higher Medicaid payment levels to dentists between 2000 and 2008 were more likely to receive dental care, although children covered by Medicaid received dental care less often than children with private insurance, according to a study in the July 13 issue of JAMA.
According to background information in the article, more than one-third of children are covered by public health insurance, primarily Medicaid and the Children's Health Insurance Program (CHIP). Coverage of dental care for children and adolescents covered by Medicaid and CHIP is required, although states have wide latitude in setting payment rates for providers including dentists, with these rates varying greatly by state. Medicaid recipients may not be able to access dental care if dentists decline to participate in Medicaid because of low payment levels or other reasons. Little is known about the effect of state dental fees on participation of dentists in the Medicaid program.
Sandra L. Decker, Ph.D., of the Centers for Disease Control and Prevention, Hyattsville, Md., conducted a study to examine the association of state Medicaid payment rates for dental care with the receipt of dental care among children covered by Medicaid. The study included data on Medicaid dental fees in 2000 and 2008 for 42 states plus the District of Columbia, and these data were merged with data from 33,657 children and adolescents (ages 2-17 years) in the National Health Interview Survey (NHIS) for the years 2000-2001 and 2008-2009.
Of the 42 states plus the District of Columbia considered in the analyses, the 2008 Medicaid dental fees were lower than the (inflation-adjusted) 2000 fees in 23 states. Payment levels to dentists in 2008 were higher than in 2000 in 19 states plus the District of Columbia. In five states (Connecticut, Indiana, Montana, New York, and Texas) plus the District of Columbia, payments increased by at least 50 percent between 2000 and 2008.
The researchers found that the probability that a child or adolescent had seen a dentist in the past 6 months varied by insurance source. In 2008-2009, children and adolescents covered by Medicaid were less likely (55 percent) than children with private insurance (68 percent) to have seen a dentist in the past 6 months, but were more likely to have seen a dentist than children or adolescents without insurance (27 percent). According to the author's, "children were about 6 percentage points more likely to have seen a dentist in 2008-2009 than in 2000-2001. … Those covered by Medicaid or CHIP were about 13 percentage points and uninsured children were about 40 percentage points less likely than children with private insurance to have seen a dentist."
"Changes in state Medicaid dental payment fees between 2000 and 2008 were positively associated with use of dental care among children and adolescents covered by Medicaid. For example, a $10 increase in the Medicaid prophylaxis payment level (from $20 to $30) was associated with a 3.92 percentage point increase in the chance that a child or adolescent covered by Medicaid had seen a dentist," the authors write.
"As future expansions in Medicaid eligibility and insurance coverage more generally are contemplated and possibly implemented, more attention to the effects of provider payment policies on access to care, quality of care, and health outcomes may be warranted."
Wednesday, July 6, 2011
Dentists are a major source of opioid drugs
With a cover article in the July edition of the Journal of the American Dental Association (JADA), dentists focus that spotlight on themselves both as major sources of opioid drugs and as professionals with largely untapped power to recognize and reduce abuse.
“Many dentists really haven’t even perceived there to be a problem,” said George Kenna, an assistant professor of psychiatry and human behavior at the Warren Alpert Medical School of Brown University, an addiction psychologist at the Center for Alcohol and Addiction Studies, and the corresponding author of the article. “Dentists write the third-most prescriptions for immediate release opioids in the United States, but they often don’t know the appropriate number of doses to prescribe, how many doses a patient uses, or most importantly what patients do with the leftover tablets they have. Just ask someone the last time they threw away opioid prescriptions in particular. These leftover tablets — accumulated from various sources, not just dentists — that are often left in closets across the country are the primary source for prescription drug use initiation for children and adolescents.”
Last year Kenna helped lead a meeting of dentists and fellow addiction experts and pharmacists at the Tufts Health Care Institute Program on Opioid Risk Management, where he serves as a scientific adviser. The group produced this month’s cover article for JADA, which offered several recommendations for dentists, including:
• Discuss with patients whether they need an opioid for their pain and how likely they are to use what you prescribe.
• Consider writing small quantities and limit refills.
• Do not prescribe drugs to patients you do not know; be suspicious of those who claim their drugs were lost or stolen.
• Use prescription monitoring programs (i.e., state databases), if available, to verify drug-use history.
• Advise patients either to destroy or lockup any excess medication.
• Keep prescription pads locked up.
In the article, the nine authors also call for more research to make the most effective use of opioid and non-opioid painkillers, for instance to determine how much painkiller and which kind patients really need. Without enough evidence to guide them, dentists have often felt obliged to prescribe opioids too often and in too great a quantity, Kenna said.
“Some new data show that ibuprofen as an anti-inflammatory does as well as many painkillers to kill pain for many dental procedures,” Kenna said.
One in two dentists surveyed
Despite the large role dentists have as painkiller prescribers, there has been very little research on dentists’ prescribing practices and experiences, particularly in the context of opioid addiction. To inform their discussion, the group commissioned a survey in 2010, led by Michael O’Neil, a pharmacy professor at the University of Charleston in West Virginia. In all, 52 percent of the state’s dentists responded.
The survey revealed that nine in 10 of the dentists surveyed prescribed opioids in the prior year. Two-thirds prescribed between 10 and 20 doses of the painkillers, but 41 percent acknowledged that patients would probably have some left over.
The survey also found some evidence that dentists can sometimes be shy about raising substance abuse as an issue with patients, even as they realize they are sometimes being used to get drugs. One in three of the dentists said they did not routinely ask new patients about substance abuse, but 58 percent of the dentists said they believed they have been the victim of prescription fraud or theft.
While dentists should guard against over-prescribing addictive drugs, especially to patients they don’t know well, Kenna said, they retain an obligation to help all patients, even ones who are addicted, to manage pain.
“There are ways that dentists can work with patients,” he said. “People who have a substance abuse problem do have legitimate pain. They do have a right to have some pain control and may even need more. But you hope there is a family member who will take control and make sure they only take the recommended dose.”
For all the things dentists could do, especially with more research to clarify the best prescribing practices, Kenna acknowledged that dentists are not currently compensated for the time required to investigate the drug use preferences and habits of their patients.
Kenna said he hopes to learn more about how the profession approaches opioids and addiction with a national survey of dentists.
“It’s a growing problem in the United States,” he said. “It’s a serious problem.”
“Many dentists really haven’t even perceived there to be a problem,” said George Kenna, an assistant professor of psychiatry and human behavior at the Warren Alpert Medical School of Brown University, an addiction psychologist at the Center for Alcohol and Addiction Studies, and the corresponding author of the article. “Dentists write the third-most prescriptions for immediate release opioids in the United States, but they often don’t know the appropriate number of doses to prescribe, how many doses a patient uses, or most importantly what patients do with the leftover tablets they have. Just ask someone the last time they threw away opioid prescriptions in particular. These leftover tablets — accumulated from various sources, not just dentists — that are often left in closets across the country are the primary source for prescription drug use initiation for children and adolescents.”
Last year Kenna helped lead a meeting of dentists and fellow addiction experts and pharmacists at the Tufts Health Care Institute Program on Opioid Risk Management, where he serves as a scientific adviser. The group produced this month’s cover article for JADA, which offered several recommendations for dentists, including:
• Discuss with patients whether they need an opioid for their pain and how likely they are to use what you prescribe.
• Consider writing small quantities and limit refills.
• Do not prescribe drugs to patients you do not know; be suspicious of those who claim their drugs were lost or stolen.
• Use prescription monitoring programs (i.e., state databases), if available, to verify drug-use history.
• Advise patients either to destroy or lockup any excess medication.
• Keep prescription pads locked up.
In the article, the nine authors also call for more research to make the most effective use of opioid and non-opioid painkillers, for instance to determine how much painkiller and which kind patients really need. Without enough evidence to guide them, dentists have often felt obliged to prescribe opioids too often and in too great a quantity, Kenna said.
“Some new data show that ibuprofen as an anti-inflammatory does as well as many painkillers to kill pain for many dental procedures,” Kenna said.
One in two dentists surveyed
Despite the large role dentists have as painkiller prescribers, there has been very little research on dentists’ prescribing practices and experiences, particularly in the context of opioid addiction. To inform their discussion, the group commissioned a survey in 2010, led by Michael O’Neil, a pharmacy professor at the University of Charleston in West Virginia. In all, 52 percent of the state’s dentists responded.
The survey revealed that nine in 10 of the dentists surveyed prescribed opioids in the prior year. Two-thirds prescribed between 10 and 20 doses of the painkillers, but 41 percent acknowledged that patients would probably have some left over.
The survey also found some evidence that dentists can sometimes be shy about raising substance abuse as an issue with patients, even as they realize they are sometimes being used to get drugs. One in three of the dentists said they did not routinely ask new patients about substance abuse, but 58 percent of the dentists said they believed they have been the victim of prescription fraud or theft.
While dentists should guard against over-prescribing addictive drugs, especially to patients they don’t know well, Kenna said, they retain an obligation to help all patients, even ones who are addicted, to manage pain.
“There are ways that dentists can work with patients,” he said. “People who have a substance abuse problem do have legitimate pain. They do have a right to have some pain control and may even need more. But you hope there is a family member who will take control and make sure they only take the recommended dose.”
For all the things dentists could do, especially with more research to clarify the best prescribing practices, Kenna acknowledged that dentists are not currently compensated for the time required to investigate the drug use preferences and habits of their patients.
Kenna said he hopes to learn more about how the profession approaches opioids and addiction with a national survey of dentists.
“It’s a growing problem in the United States,” he said. “It’s a serious problem.”
Gum disease can increase the time it takes to become pregnant
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For the first time, fertility experts have shown that, from the time that a woman starts trying to conceive, poor oral health can have a significant effect on the time to pregnancy.
Professor Roger Hart told the annual meeting of the European Society of Human Reproduction and Embryology that the negative effect of gum disease on conception was of the same order of magnitude as the effect of obesity.
Periodontal (gum) disease is a chronic, infectious and inflammatory disease of the gums and supporting tissues. It is caused by the normal bacteria that exist in everyone's mouths, which, if unchecked, can create inflammation around the tooth; the gum starts to pull away from the tooth, creating spaces (periodontal pockets) that become infected. The inflammation sets off a cascade of tissue-destructive events that can pass into the circulation. As a result, periodontal disease has been associated with heart disease, type 2 diabetes, respiratory and kidney disease, and problems in pregnancy such as miscarriage and premature birth. Around 10% of the population is believed to have severe periodontal disease. Regular brushing and flossing of teeth is the best way of preventing it.
Prof Hart, who is Professor of Reproductive Medicine at the University of Western Australia (Perth, Australia) and Medical Director of Fertility Specialists of Western Australia, said: "Until now, there have been no published studies that investigate whether gum disease can affect a woman's chance of conceiving, so this is the first report to suggest that gum disease might be one of several factors that could be modified to improve the chances of a pregnancy."
The researchers followed a group 3737 pregnant women, who were taking part in a Western Australian study called the SMILE study, and they analysed information on pregnancy planning and pregnancy outcomes for 3416 of them.
They found that women with gum disease took an average of just over seven months to become pregnant – two months longer than the average of five months that it took women without gum disease to conceive.
In addition, non-Caucasian women with gum disease were more likely to take over a year to become pregnant compared to those without gum disease: their increased risk of later conception was 13.9% compared to 6.2% for women without gum disease. Caucasian women with gum disease also tended to take longer to conceive than those who were disease-free but the difference was not statistically significant (8.6% of Caucasian women with gum disease took over one year to conceive and 6.2% of women with gum disease).
Information on time to conception was available for 1,956 women, and of, these, 146 women took longer than 12 months to conceive – an indicator of impaired fertility. They were more likely to be older, non-Caucasian, to smoke and to have a body mass index over 25 kg/m2. Out of the 3416 women, 1014 (26%) had periodontal disease.
Prof Hart said: "Our data suggest that the presence of periodontal disease is a modifiable risk factor, which can increase a woman's time to conception, particularly for non-Caucasians. It exerts a negative influence on fertility that is of the same order of magnitude as obesity. This study also confirms other, known negative influences upon time to conception for a woman; these include being over 35 years of age, being overweight or obese, and being a smoker. There was no correlation between the time it took to become pregnant and the socio-economic status of the woman.
"All women about to plan for a family should be encouraged to see their general practitioner to ensure that they are as healthy as possible before trying to conceive and so that they can be given appropriate lifestyle advice with respect to weight loss, diet and assistance with stopping smoking and drinking, plus the commencement of folic acid supplements. Additionally, it now appears that all women should also be encouraged to see their dentist to have any gum disease treated before trying to conceive. It is easily treated, usually involving no more than four dental visits.
"The SMILE study was one of the three largest randomised controlled trials performed in Western Australia. It showed conclusively that although treatment of periodontal disease does not prevent pre-term birth in any ethnic group, the treatment itself does not have any harmful effect on the mother or foetus during pregnancy*."
Prof Hart said that the reason why pregnancies in non-Caucasian women were more affected by gum disease could be because these women appeared to have a higher level of inflammatory response to the condition.
For the first time, fertility experts have shown that, from the time that a woman starts trying to conceive, poor oral health can have a significant effect on the time to pregnancy.
Professor Roger Hart told the annual meeting of the European Society of Human Reproduction and Embryology that the negative effect of gum disease on conception was of the same order of magnitude as the effect of obesity.
Periodontal (gum) disease is a chronic, infectious and inflammatory disease of the gums and supporting tissues. It is caused by the normal bacteria that exist in everyone's mouths, which, if unchecked, can create inflammation around the tooth; the gum starts to pull away from the tooth, creating spaces (periodontal pockets) that become infected. The inflammation sets off a cascade of tissue-destructive events that can pass into the circulation. As a result, periodontal disease has been associated with heart disease, type 2 diabetes, respiratory and kidney disease, and problems in pregnancy such as miscarriage and premature birth. Around 10% of the population is believed to have severe periodontal disease. Regular brushing and flossing of teeth is the best way of preventing it.
Prof Hart, who is Professor of Reproductive Medicine at the University of Western Australia (Perth, Australia) and Medical Director of Fertility Specialists of Western Australia, said: "Until now, there have been no published studies that investigate whether gum disease can affect a woman's chance of conceiving, so this is the first report to suggest that gum disease might be one of several factors that could be modified to improve the chances of a pregnancy."
The researchers followed a group 3737 pregnant women, who were taking part in a Western Australian study called the SMILE study, and they analysed information on pregnancy planning and pregnancy outcomes for 3416 of them.
They found that women with gum disease took an average of just over seven months to become pregnant – two months longer than the average of five months that it took women without gum disease to conceive.
In addition, non-Caucasian women with gum disease were more likely to take over a year to become pregnant compared to those without gum disease: their increased risk of later conception was 13.9% compared to 6.2% for women without gum disease. Caucasian women with gum disease also tended to take longer to conceive than those who were disease-free but the difference was not statistically significant (8.6% of Caucasian women with gum disease took over one year to conceive and 6.2% of women with gum disease).
Information on time to conception was available for 1,956 women, and of, these, 146 women took longer than 12 months to conceive – an indicator of impaired fertility. They were more likely to be older, non-Caucasian, to smoke and to have a body mass index over 25 kg/m2. Out of the 3416 women, 1014 (26%) had periodontal disease.
Prof Hart said: "Our data suggest that the presence of periodontal disease is a modifiable risk factor, which can increase a woman's time to conception, particularly for non-Caucasians. It exerts a negative influence on fertility that is of the same order of magnitude as obesity. This study also confirms other, known negative influences upon time to conception for a woman; these include being over 35 years of age, being overweight or obese, and being a smoker. There was no correlation between the time it took to become pregnant and the socio-economic status of the woman.
"All women about to plan for a family should be encouraged to see their general practitioner to ensure that they are as healthy as possible before trying to conceive and so that they can be given appropriate lifestyle advice with respect to weight loss, diet and assistance with stopping smoking and drinking, plus the commencement of folic acid supplements. Additionally, it now appears that all women should also be encouraged to see their dentist to have any gum disease treated before trying to conceive. It is easily treated, usually involving no more than four dental visits.
"The SMILE study was one of the three largest randomised controlled trials performed in Western Australia. It showed conclusively that although treatment of periodontal disease does not prevent pre-term birth in any ethnic group, the treatment itself does not have any harmful effect on the mother or foetus during pregnancy*."
Prof Hart said that the reason why pregnancies in non-Caucasian women were more affected by gum disease could be because these women appeared to have a higher level of inflammatory response to the condition.
Thursday, June 30, 2011
Cause of negative outcomes for implants identified
The health of the surrounding tissue affects the success of a dental implant. Identifying and reducing risk factors is therefore a key step in the implant process. Now a combination of genes has been identified as a possible indicator of greater tissue destruction leading to negative outcomes for implants.
The authors of an article
in the current issue of the Journal of Oral Implantology report on a study of individuals with the combination of interleukin (IL)-1 allele 2 at IL-1A−889 and IL-1B+3954. These people are “genotype positive” and are susceptible to increased periodontal tissue destruction.
Peri-implantitis, or the process of tissue inflammation and destruction around failing implants, is very similar to periodontal disease. The researchers sought to find any association of these genotypes with the severity of peri-implantitis progression and the effect of this combination on treatment outcomes.
This study compared two groups of patients, all of whom had implants. The first group consisted of 25 patients with peri-implantitis, while the second group of 25 patients had healthy tissue. Seventeen patients from the first group and five from the second group were genotype positive.
Patients in the first group, those with peri-implantitis, took part in a treatment and maintenance program. The genotype-positive patients in this group experienced greater periodontal tissue destruction and, increased discharge from tissues. The genotype-negative patients responded better to treatment. Statistically significant differences were noted between the groups.
The combination of these two alleles in patients with inflamed periodontal tissues denotes a risk factor that can lead to further tissue destruction. Patients with the specific genotype can have exaggerated local inflammation. Gene polymorphism may affect the outcomes of treatment for peri-implantitis in genotype-positive people and affect the long-term success of implants.
Full text of the article, “
The Effect of Interleukin-1 Allele 2 Genotype (IL-1a−889 and IL-1b+3954) on the Individual’s Susceptibility to Peri-Implantitis: Case-Control Study,” Journal of Oral Implantology, Vol. 37, No. 3, 2011, is available at http://allenpress.com/publications/journals/orim
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About Journal of Oral Implantology
The Journal of Oral Implantology is the official publication of the American Academy of Implant Dentistry and of the American Academy of Implant Prosthodontics. It is dedicated to providing valuable information to general dentists, oral surgeons, prosthodontists, periodontists, scientists, clinicians, laboratory owners and technicians, manufacturers, and educators. The JOI distinguishes itself as the first and oldest journal in the world devoted exclusively to implant dentistry. For more information about the journal or society, please visit here.
Monday, June 27, 2011
How Cavity-Causing Microbes Invade Heart
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Scientists have discovered the tool that bacteria normally found in our mouths use to invade heart tissue, causing a dangerous and sometimes lethal infection of the heart known as endocarditis. The work raises the possibility of creating a screening tool – perhaps a swab of the cheek, or a spit test – to gauge a dental patient’s vulnerability to the condition.
The identification of the protein that allows Streptococcus mutans to gain a foothold in heart tissue is reported in the June issue of Infection and Immunity by microbiologists at the University of Rochester Medical Center.
S. mutans is a bacterium best known for causing cavities. The bacteria reside in dental plaque – an architecturally sophisticated goo composed of an elaborate molecular matrix created by S. mutans that allows the bacteria to inhabit and thrive in our oral cavity. There, they churn out acid that erodes our teeth.
S. mutans invading a human coronary artery endothelial cell.
Normally, S. mutans confines its mischief to the mouth, but sometimes, particularly after a dental procedure or even after a vigorous bout of flossing, the bacteria enter the bloodstream. There, the immune system usually destroys them, but occasionally – within just a few seconds – they travel to the heart and colonize its tissue, especially heart valves. The bacteria can cause endocarditis – inflammation of heart valves – which can be deadly. Infection by S. mutans is a leading cause of the condition.
“When I first learned that S. mutans sometimes can live in the heart, I asked myself: Why in the world are these bacteria, which normally live in the mouth, in the heart? I was intrigued. And I began investigating how they get there and survive there,” said Jacqueline Abranches, Ph.D., a microbiologist and the corresponding author of the study.
Abranches and her team at the University’s Center for Oral Biology discovered that a collagen-binding protein known as CNM gives S. mutans its ability to invade heart tissue. In laboratory experiments, scientists found that strains with CNM are able to invade heart cells, and strains without CNM are not.
When the team knocked out the gene for CNM in strains where it’s normally present, the bacteria were unable to invade heart tissue. Without CNM, the bacteria simply couldn’t gain a foothold; their ability to adhere was about one-tenth of what it was with CNM.
The team also studied the response of wax worms to the various strains of S. mutans. They found that strains without CNM were rarely lethal to the worms, while strains with the protein were lethal 90 percent of the time. Then, when Abranches’ team knocked out CNM in those strains, they were no longer lethal – those worms thrived.
The work may someday enable doctors to prevent S. mutans from invading heart tissue. Even sooner, though, since some strains of S. mutans have CNM and others do not, the research may enable doctors to gauge a patient’s vulnerability to a heart infection caused by the bacteria.
Abranches has identified five specific strains of S. mutans that carry the CNM protein, out of more than three dozen strains examined. CNM is not found in the most common type of S. mutans found in people, type C, but is present in rarer types of S. mutans, including types E and F.
“It may be that CNM can serve as a biomarker of the most virulent strains of S. mutans,” said Abranches, a research assistant professor in the Department of Microbiology and Immunology. “When patients with cardiac problems go to the dentist, perhaps those patients will be screened to see if they carry the protein. If they do, the dentist might treat them more aggressively with preventive antibiotics, for example.”
Until more research is done and a screening or preventive tool is in place, Abranches says the usual advice for good oral health still stands for everyone.
“No matter what types of bacteria a person has in his or her mouth, they should do the same things to maintain good oral health. They should brush and floss their teeth regularly – the smaller the number of S. mutans in your mouth, the healthier you’ll be. Use a fluoride rinse before you go to bed at night. And eat a healthy diet, keeping sugar to a minimum,” added Abranches.
Abranches presented the work at a recent conference on the “oral microbiome” hosted by the University’s Center for Oral Biology. The center is part of the Medical Center’s Eastman Institute for Oral Health, a world leader in research and post-doctoral education in general and pediatric dentistry, orthodontics, periodontics, prosthodontics, and oral surgery.
Additional authors of the study include laboratory technician James Miller; former technician Alaina Martinez; Patricia Simpson-Haidaris, Ph.D., associate professor of Medicine; Robert Burne, Ph.D., of the University of Florida; and Abranches’ husband, Jose Lemos, Ph.D., of the Center for Oral Biology, who is also assistant professor in the Department of Microbiology and Immunology. The work was funded by the American Heart Association.
Scientists have discovered the tool that bacteria normally found in our mouths use to invade heart tissue, causing a dangerous and sometimes lethal infection of the heart known as endocarditis. The work raises the possibility of creating a screening tool – perhaps a swab of the cheek, or a spit test – to gauge a dental patient’s vulnerability to the condition.
The identification of the protein that allows Streptococcus mutans to gain a foothold in heart tissue is reported in the June issue of Infection and Immunity by microbiologists at the University of Rochester Medical Center.
S. mutans is a bacterium best known for causing cavities. The bacteria reside in dental plaque – an architecturally sophisticated goo composed of an elaborate molecular matrix created by S. mutans that allows the bacteria to inhabit and thrive in our oral cavity. There, they churn out acid that erodes our teeth.
S. mutans invading a human coronary artery endothelial cell.
Normally, S. mutans confines its mischief to the mouth, but sometimes, particularly after a dental procedure or even after a vigorous bout of flossing, the bacteria enter the bloodstream. There, the immune system usually destroys them, but occasionally – within just a few seconds – they travel to the heart and colonize its tissue, especially heart valves. The bacteria can cause endocarditis – inflammation of heart valves – which can be deadly. Infection by S. mutans is a leading cause of the condition.
“When I first learned that S. mutans sometimes can live in the heart, I asked myself: Why in the world are these bacteria, which normally live in the mouth, in the heart? I was intrigued. And I began investigating how they get there and survive there,” said Jacqueline Abranches, Ph.D., a microbiologist and the corresponding author of the study.
Abranches and her team at the University’s Center for Oral Biology discovered that a collagen-binding protein known as CNM gives S. mutans its ability to invade heart tissue. In laboratory experiments, scientists found that strains with CNM are able to invade heart cells, and strains without CNM are not.
When the team knocked out the gene for CNM in strains where it’s normally present, the bacteria were unable to invade heart tissue. Without CNM, the bacteria simply couldn’t gain a foothold; their ability to adhere was about one-tenth of what it was with CNM.
The team also studied the response of wax worms to the various strains of S. mutans. They found that strains without CNM were rarely lethal to the worms, while strains with the protein were lethal 90 percent of the time. Then, when Abranches’ team knocked out CNM in those strains, they were no longer lethal – those worms thrived.
The work may someday enable doctors to prevent S. mutans from invading heart tissue. Even sooner, though, since some strains of S. mutans have CNM and others do not, the research may enable doctors to gauge a patient’s vulnerability to a heart infection caused by the bacteria.
Abranches has identified five specific strains of S. mutans that carry the CNM protein, out of more than three dozen strains examined. CNM is not found in the most common type of S. mutans found in people, type C, but is present in rarer types of S. mutans, including types E and F.
“It may be that CNM can serve as a biomarker of the most virulent strains of S. mutans,” said Abranches, a research assistant professor in the Department of Microbiology and Immunology. “When patients with cardiac problems go to the dentist, perhaps those patients will be screened to see if they carry the protein. If they do, the dentist might treat them more aggressively with preventive antibiotics, for example.”
Until more research is done and a screening or preventive tool is in place, Abranches says the usual advice for good oral health still stands for everyone.
“No matter what types of bacteria a person has in his or her mouth, they should do the same things to maintain good oral health. They should brush and floss their teeth regularly – the smaller the number of S. mutans in your mouth, the healthier you’ll be. Use a fluoride rinse before you go to bed at night. And eat a healthy diet, keeping sugar to a minimum,” added Abranches.
Abranches presented the work at a recent conference on the “oral microbiome” hosted by the University’s Center for Oral Biology. The center is part of the Medical Center’s Eastman Institute for Oral Health, a world leader in research and post-doctoral education in general and pediatric dentistry, orthodontics, periodontics, prosthodontics, and oral surgery.
Additional authors of the study include laboratory technician James Miller; former technician Alaina Martinez; Patricia Simpson-Haidaris, Ph.D., associate professor of Medicine; Robert Burne, Ph.D., of the University of Florida; and Abranches’ husband, Jose Lemos, Ph.D., of the Center for Oral Biology, who is also assistant professor in the Department of Microbiology and Immunology. The work was funded by the American Heart Association.
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