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.
The article, "Remarkable resilience of teeth" appears in the April 2009 edition of Proceedings of the National Academy of Sciences.
Friday, April 17, 2009
Thursday, April 16, 2009
Baby canine teeth: No evidence to support extraction
The practice of extracting baby canine teeth to make way for adult canines that are erupting in the wrong place has no evidential basis, according to a new study by Cochrane Researchers. In a systematic review, the researchers were unable to identify a single high quality study to support the practice.
"The recommendation of extracting the baby canine is in fact based on one uncontrolled study that was carried out over twenty years ago," says lead author of the study Nicola Parkin of the Department of Oral Health and Development at the University of Sheffield.
It is common for adult upper canines to grow in the wrong place. Normally adult canine teeth erupt in the mouth around the age of 12 years and, in approximately 2-3% of the population of 12 year old children, these teeth become displaced in the roof of the mouth. Displaced canines can cause damage to neighbouring teeth as well as unfavourable movement of other teeth and, more rarely, cysts. One suggested way of avoiding canine displacement and encouraging the eruption of the adult canine is to remove a child's baby canine tooth at around 10 to 13 years, under local anaesthetic.
According to the researchers, however, the most commonly cited evidence for this practice comes from one trial, carried out in 1988, in which a group of children with canine displacement had their baby canines extracted. A major flaw of this study was the absence of a control group. Two other studies considered for the review did have an untreated control group, but had to be excluded because of inadequacies in reporting.
"Extracting the primary canine may help the secondary tooth to emerge correctly, but at this time we can't provide any hard evidence," says Dr Parkin. "Greater attention to the design and reporting of studies is needed to improve the quality of clinical trials on this topic."
"The recommendation of extracting the baby canine is in fact based on one uncontrolled study that was carried out over twenty years ago," says lead author of the study Nicola Parkin of the Department of Oral Health and Development at the University of Sheffield.
It is common for adult upper canines to grow in the wrong place. Normally adult canine teeth erupt in the mouth around the age of 12 years and, in approximately 2-3% of the population of 12 year old children, these teeth become displaced in the roof of the mouth. Displaced canines can cause damage to neighbouring teeth as well as unfavourable movement of other teeth and, more rarely, cysts. One suggested way of avoiding canine displacement and encouraging the eruption of the adult canine is to remove a child's baby canine tooth at around 10 to 13 years, under local anaesthetic.
According to the researchers, however, the most commonly cited evidence for this practice comes from one trial, carried out in 1988, in which a group of children with canine displacement had their baby canines extracted. A major flaw of this study was the absence of a control group. Two other studies considered for the review did have an untreated control group, but had to be excluded because of inadequacies in reporting.
"Extracting the primary canine may help the secondary tooth to emerge correctly, but at this time we can't provide any hard evidence," says Dr Parkin. "Greater attention to the design and reporting of studies is needed to improve the quality of clinical trials on this topic."
HOME TOOTH BLEACHING REDUCES ENAMEL STRENGTH
HOME TOOTH BLEACHING SLIGHTLY REDUCES ENAMEL STRENGTH
New research shows that human teeth lost some enamel hardness after the application of several different products used in the home to whiten teeth. The study suggests that future generations of such products might be reformulated in an effort to reduce these side effects.
The researchers noted that teeth typically can restore their previous hardness after losing small amounts of enamel calcification. But this is the first study to show at a nanometer scale – measuring in billionths of a meter – how human teeth are affected by the popular home whiteners.“There is some significant reduction in nano-hardness of enamel, but we are talking on a very minute scale. So even though it may not be visible to the human eye, it’s important for research because that’s how we improve products,” said Shereen Azer, assistant professor of restorative and prosthetic dentistry at Ohio State University and lead author of the study.
Azer and colleagues applied the recommended treatments of five name-brand home whiteners to samples of human teeth and compared the effects to tooth samples that received no treatment. In all cases, the products reduced the hardness of the enamel as well as what is called the elastic modulus or stiffness, a measure of the ability of the tooth surface to bounce back in response to applied force.
Many studies have sought to determine how tooth whitening affects tooth enamel hardness, but results have been inconclusive. Azer said that previous studies measured the loss of enamel hardness in microns, or millionths of a meter, rather than on the nanometer scale used in his study.
“So this just gives us a better understanding of precisely how these products affect human teeth,” he said.
The research is published in a recent issue of the Journal of Dentistry.
Tooth bleaching products contain solutions of various strengths of either hydrogen peroxide or carbamide peroxide, which provide the whitening effect. They bleach teeth by producing unstable free radicals that attack pigment molecules in the organic parts of enamel. The reduction in pigment means the molecules no longer reflect light, so the teeth appear whiter.
Enamel, which is almost entirely inorganic and translucent, appears yellow in most teeth because it reflects the color of the dentin underneath, which is naturally yellow.
“Especially nowadays, people tend to see beauty in white teeth,” Azer said. “And bleaching does have a beautiful effect, but not without side effects.”
The study did not test for two other common side effects of tooth whitening, gum irritation and tooth sensitivity. Azer said these side effects have been addressed by other products, such as toothpastes and treatment gels designed to lessen sensitivity and irritation.
He and colleagues used extracted molars to assemble 65 human tooth samples measuring 4 millimeters square and 2 millimeters deep for the study. Ten samples were used in a pilot study that determined they could achieve accurate results for the research under dry conditions rather than wet conditions simulating the presence of saliva.
Of the remaining samples, five were left untreated, and 50 were divided into five groups of 10 each to undergo treatment.
The researchers used whitening strips on two groups of samples and trays filled with whitening gel on three groups. The treatment times included up to 60 minutes once per day or 60 minutes twice per day according to manufacturer recommendations. All treatments lasted for three weeks except for one tray method, which lasted 10 days.
The treatments included both over-the-counter and professionally provided products to be used in the home.
The scientists used a specialized tool to apply force to test the enamel hardness and stiffness (the surface ability to bounce back), and an atomic force microscope to observe the tiny nanometer-scale effects on the teeth.
The average loss of enamel ranged from 1.2 to 2 nanometers on the treated teeth. The control teeth, on average, actually gained 0.4 nanometers of hardness in comparison over the treatment time frame. The surface ability to bounce back from applied force was reduced by an average of between 6 percent and 18.8 percent among the treated teeth, depending on the type of treatment.
Among the different products, most of the reductions in hardness and elastic modulus were similar. However, there was a significant difference between one strip treatment method and one tray method, with the tray method reducing enamel hardness more dramatically than the strip treatment.
Enamel is the hardest structure in the human body. It protects teeth and maintains the integrity of the bite. But enamel is subject to abrasion by certain products and even too-vigorous brushing, which is why it is important to figure out ways to reduce damage to this part of the tooth, Azer said.
“In the case of these products, manufacturers might be able to alter the concentrations of the materials and the vehicles used to apply the bleach,” he said.
The study did not address how to restore hardness to bleached teeth, but Azer noted that extensive research has indicated that fluoride treatments, including the use of fluoride toothpaste, can promote enamel remineralization.
The products used in the study were Crest Whitestrips Premium Plus, Crest Whitestrips Supreme, Nite White ACP, Oral B Rembrandt and Treswhite Opalescence. The final three are tray treatments.
Azer conducted the research with Camilo Machado and Robert Rashid of the Division of Restorative and Prosthetic Dentistry and Eliana Sanchez of the Division of Primary Care, all in Ohio State’s College of Dentistry.
New research shows that human teeth lost some enamel hardness after the application of several different products used in the home to whiten teeth. The study suggests that future generations of such products might be reformulated in an effort to reduce these side effects.
The researchers noted that teeth typically can restore their previous hardness after losing small amounts of enamel calcification. But this is the first study to show at a nanometer scale – measuring in billionths of a meter – how human teeth are affected by the popular home whiteners.“There is some significant reduction in nano-hardness of enamel, but we are talking on a very minute scale. So even though it may not be visible to the human eye, it’s important for research because that’s how we improve products,” said Shereen Azer, assistant professor of restorative and prosthetic dentistry at Ohio State University and lead author of the study.
Azer and colleagues applied the recommended treatments of five name-brand home whiteners to samples of human teeth and compared the effects to tooth samples that received no treatment. In all cases, the products reduced the hardness of the enamel as well as what is called the elastic modulus or stiffness, a measure of the ability of the tooth surface to bounce back in response to applied force.
Many studies have sought to determine how tooth whitening affects tooth enamel hardness, but results have been inconclusive. Azer said that previous studies measured the loss of enamel hardness in microns, or millionths of a meter, rather than on the nanometer scale used in his study.
“So this just gives us a better understanding of precisely how these products affect human teeth,” he said.
The research is published in a recent issue of the Journal of Dentistry.
Tooth bleaching products contain solutions of various strengths of either hydrogen peroxide or carbamide peroxide, which provide the whitening effect. They bleach teeth by producing unstable free radicals that attack pigment molecules in the organic parts of enamel. The reduction in pigment means the molecules no longer reflect light, so the teeth appear whiter.
Enamel, which is almost entirely inorganic and translucent, appears yellow in most teeth because it reflects the color of the dentin underneath, which is naturally yellow.
“Especially nowadays, people tend to see beauty in white teeth,” Azer said. “And bleaching does have a beautiful effect, but not without side effects.”
The study did not test for two other common side effects of tooth whitening, gum irritation and tooth sensitivity. Azer said these side effects have been addressed by other products, such as toothpastes and treatment gels designed to lessen sensitivity and irritation.
He and colleagues used extracted molars to assemble 65 human tooth samples measuring 4 millimeters square and 2 millimeters deep for the study. Ten samples were used in a pilot study that determined they could achieve accurate results for the research under dry conditions rather than wet conditions simulating the presence of saliva.
Of the remaining samples, five were left untreated, and 50 were divided into five groups of 10 each to undergo treatment.
The researchers used whitening strips on two groups of samples and trays filled with whitening gel on three groups. The treatment times included up to 60 minutes once per day or 60 minutes twice per day according to manufacturer recommendations. All treatments lasted for three weeks except for one tray method, which lasted 10 days.
The treatments included both over-the-counter and professionally provided products to be used in the home.
The scientists used a specialized tool to apply force to test the enamel hardness and stiffness (the surface ability to bounce back), and an atomic force microscope to observe the tiny nanometer-scale effects on the teeth.
The average loss of enamel ranged from 1.2 to 2 nanometers on the treated teeth. The control teeth, on average, actually gained 0.4 nanometers of hardness in comparison over the treatment time frame. The surface ability to bounce back from applied force was reduced by an average of between 6 percent and 18.8 percent among the treated teeth, depending on the type of treatment.
Among the different products, most of the reductions in hardness and elastic modulus were similar. However, there was a significant difference between one strip treatment method and one tray method, with the tray method reducing enamel hardness more dramatically than the strip treatment.
Enamel is the hardest structure in the human body. It protects teeth and maintains the integrity of the bite. But enamel is subject to abrasion by certain products and even too-vigorous brushing, which is why it is important to figure out ways to reduce damage to this part of the tooth, Azer said.
“In the case of these products, manufacturers might be able to alter the concentrations of the materials and the vehicles used to apply the bleach,” he said.
The study did not address how to restore hardness to bleached teeth, but Azer noted that extensive research has indicated that fluoride treatments, including the use of fluoride toothpaste, can promote enamel remineralization.
The products used in the study were Crest Whitestrips Premium Plus, Crest Whitestrips Supreme, Nite White ACP, Oral B Rembrandt and Treswhite Opalescence. The final three are tray treatments.
Azer conducted the research with Camilo Machado and Robert Rashid of the Division of Restorative and Prosthetic Dentistry and Eliana Sanchez of the Division of Primary Care, all in Ohio State’s College of Dentistry.
Wednesday, April 15, 2009
Some orthodontic appliances prone to bacteria
Researchers at the Oregon Health & Science University School of Dentistry (www.ohsu.edu/sod) have found the majority of patients with self-ligating orthodontic brackets retain fewer bacteria in plaque than patients with elastomeric orthodontic brackets. The OHSU team also found that a biochemical technique measuring ATP- (adenosine triphosphate-) driven bioluminescence could be a useful chair-side tool in the rapid quantification of oral bacteria and in the assessment of oral hygiene during orthodontic treatment.
The findings are published in the April 2009 issue of the American Journal of Orthodontics and Dentofacial Orthopedics, one of the leading peer-reviewed orthodontia journals.
Acid-producing bacteria that surround orthodontic appliances are a common orthodontic problem. Such bacteria can lead to tooth enamel breakdown and potential discoloration of the tooth surface, and these aesthetic changes can persist for many years after orthodontic treatment. While the newer bonded orthodontic brackets have many advantages over the old metal bands that were fitted around each tooth, they do impede good oral hygiene, resulting in plaque accumulation and increased tooth enamel breakdown.
While several studies have investigated the effects of fixed orthodontic appliances on bacterial flora, few studies have compared the effects of bracket architecture – specifically the archwire ligation method – or have evaluated the accumulation of bacteria that occurs with the bonding of fixed appliances. The OHSU study also was different from other studies in that it was a randomized clinical study, comparing the numbers of oral bacteria in plaque surrounding two distinct orthodontic appliances, self-ligating versus elastomeric ligating, using a split-mouth design.
The OHSU study examined 14 patients aged 11 to 17, each patient containing both self-ligating and elastomeric orthodontic brackets on opposing sides of the mouth, at both one week and five weeks after bonding. The numbers of oral bacteria in plaque surrounding the brackets were evaluated at both appointments, in addition to a pre-bonding appointment, using both conventional plating techniques enumerating bacterial colony number and the ATP-driven bioluminescence technique.
More bacteria, including oral streptococci, were retained at tooth surfaces in plaque in patients with elastomeric orthodontic brackets at both the one- and five-week post-bonding appointments, and bacterial levels were particularly high at the one-week visit. Higher ATP-driven bioluminescence levels were also observed in plaque surrounding the elastomeric orthodontic appliances.
"We were surprised that the manner of ligation promoted differences in the levels of plaque bacteria surrounding the bonded tooth surfaces," noted Curt Machida, Ph.D., OHSU professor of integrative biosciences and principal investigator, whose lab was host for the study. "Our results suggest that the use of the self-ligating appliances promote reduced retention of plaque bacteria on tooth surfaces surrounding the appliances.
"Our study also provided validation that ATP-driven bioluminescence can be used as a way to quantify bacteria rapidly and reliably at the dental chair-side," he said.
The findings are published in the April 2009 issue of the American Journal of Orthodontics and Dentofacial Orthopedics, one of the leading peer-reviewed orthodontia journals.
Acid-producing bacteria that surround orthodontic appliances are a common orthodontic problem. Such bacteria can lead to tooth enamel breakdown and potential discoloration of the tooth surface, and these aesthetic changes can persist for many years after orthodontic treatment. While the newer bonded orthodontic brackets have many advantages over the old metal bands that were fitted around each tooth, they do impede good oral hygiene, resulting in plaque accumulation and increased tooth enamel breakdown.
While several studies have investigated the effects of fixed orthodontic appliances on bacterial flora, few studies have compared the effects of bracket architecture – specifically the archwire ligation method – or have evaluated the accumulation of bacteria that occurs with the bonding of fixed appliances. The OHSU study also was different from other studies in that it was a randomized clinical study, comparing the numbers of oral bacteria in plaque surrounding two distinct orthodontic appliances, self-ligating versus elastomeric ligating, using a split-mouth design.
The OHSU study examined 14 patients aged 11 to 17, each patient containing both self-ligating and elastomeric orthodontic brackets on opposing sides of the mouth, at both one week and five weeks after bonding. The numbers of oral bacteria in plaque surrounding the brackets were evaluated at both appointments, in addition to a pre-bonding appointment, using both conventional plating techniques enumerating bacterial colony number and the ATP-driven bioluminescence technique.
More bacteria, including oral streptococci, were retained at tooth surfaces in plaque in patients with elastomeric orthodontic brackets at both the one- and five-week post-bonding appointments, and bacterial levels were particularly high at the one-week visit. Higher ATP-driven bioluminescence levels were also observed in plaque surrounding the elastomeric orthodontic appliances.
"We were surprised that the manner of ligation promoted differences in the levels of plaque bacteria surrounding the bonded tooth surfaces," noted Curt Machida, Ph.D., OHSU professor of integrative biosciences and principal investigator, whose lab was host for the study. "Our results suggest that the use of the self-ligating appliances promote reduced retention of plaque bacteria on tooth surfaces surrounding the appliances.
"Our study also provided validation that ATP-driven bioluminescence can be used as a way to quantify bacteria rapidly and reliably at the dental chair-side," he said.
Friday, April 3, 2009
Periodontal disease = risk factor for HIV-1
Can periodontal disease act as a risk factor for HIV-1?
Today, during the 87th General Session of the International Association for Dental Research, convening at the Miami Beach Convention Center, a group of scientists from Nihon University (Tokyo, Japan) will present findings suggesting that periodontal disease could act as a risk factor for reactivating latent HIV-1 in affected individuals.
Latently infected cells harbor HIV-1 proviral DNA genomes integrated with heterochromatins, allowing for the persistence of transcriptionally silent proviruses. Hypoacetylation of histone proteins by histone deacetylases (HDACs) is primarily involved in the maintenance of HIV-1 latency by repressing transcription from HIV-1 provirus. On the other hand, periodontal diseases, caused by infection with the bacterium Porphyromonas gingivalis (P. gingivalis), are found worldwide and are among the most prevalent microbial diseases of mankind.
The investigators demonstrated the effects of such periodontopathic bacteria on HIV-1 replication. They found that P. gingivalis could strongly facilitate HIV-1 reactivation via chromatin modification. The bacteria produced high concentrations of butyric acid, a potent inhibitor of HDACs, and induced acetylation of histones, leading to reactivation of HIV-1 in latently infected cells. These results suggest that periodontal disease could act as a risk-factor for HIV-1 reactivation in latently infected individuals, and might contribute to the systemic dissemination of the virus causing clinical progression of acquired immunodeficiency syndrome (AIDS). The findings emphasize the essential role of maintaining oral hygiene and controlling oral diseases for the prevention of AIDS.
Today, during the 87th General Session of the International Association for Dental Research, convening at the Miami Beach Convention Center, a group of scientists from Nihon University (Tokyo, Japan) will present findings suggesting that periodontal disease could act as a risk factor for reactivating latent HIV-1 in affected individuals.
Latently infected cells harbor HIV-1 proviral DNA genomes integrated with heterochromatins, allowing for the persistence of transcriptionally silent proviruses. Hypoacetylation of histone proteins by histone deacetylases (HDACs) is primarily involved in the maintenance of HIV-1 latency by repressing transcription from HIV-1 provirus. On the other hand, periodontal diseases, caused by infection with the bacterium Porphyromonas gingivalis (P. gingivalis), are found worldwide and are among the most prevalent microbial diseases of mankind.
The investigators demonstrated the effects of such periodontopathic bacteria on HIV-1 replication. They found that P. gingivalis could strongly facilitate HIV-1 reactivation via chromatin modification. The bacteria produced high concentrations of butyric acid, a potent inhibitor of HDACs, and induced acetylation of histones, leading to reactivation of HIV-1 in latently infected cells. These results suggest that periodontal disease could act as a risk-factor for HIV-1 reactivation in latently infected individuals, and might contribute to the systemic dissemination of the virus causing clinical progression of acquired immunodeficiency syndrome (AIDS). The findings emphasize the essential role of maintaining oral hygiene and controlling oral diseases for the prevention of AIDS.
Sports drink consumption can cause tooth erosion
While sipping on sports drinks all day may provide an energy boost, this popular practice is also exposing people to levels of acid that can cause tooth erosion and hypersensitivity, NYU dental researchers have found.
In a recent study, the researchers found that prolonged consumption of sports drinks may be linked to a condition known as erosive tooth wear, in which acids eat away the tooth's smooth hard enamel coating and trickle into the bonelike material underneath, causing the tooth to soften and weaken. The condition affects one in 15 Americans and can result in severe tooth damage and even tooth loss if left untreated.
"This is the first time that the citric acid in sports drinks has been linked to erosive tooth wear," said Dr. Mark Wolff, Professor and Chairman of the Department of Cariology & Comprehensive Care at New York University College of Dentistry, who led the study. The findings were presented today at the annual meeting of the International Association for Dental Research in Miami.
Dr. Wolff's research team cut in half cow teeth, which were used for the study because of their close resemblance to human teeth. They immersed one half of the specimens in a sports drink, the other half in water, then compared the two halves and discovered that the one exposed to the sports drink displayed a significant amount of erosion and softening.
"Five teeth were immersed in each drink for 75 to 90 minutes to simulate the effects of sipping on sports drinks over the course of the day," Dr. Wolff said. The researchers evaluated the effects of a range of top-selling sports drinks on the cow teeth.
According to Dr. Wolff, brushing teeth immediately after consuming a sports drink can compound the problem of tooth erosion, because softened enamel is very susceptible to the abrasive properties of toothpaste.
"To prevent tooth erosion, consume sports drinks in moderation, and wait at least 30 minutes before brushing your teeth, to allow softened enamel to re-harden," Dr. Wolff advised. "If you frequently consume sports drinks, ask your dentist if you should use an acid-neutralizing remineralizing toothpaste to help re-harden soft enamel."
In a recent study, the researchers found that prolonged consumption of sports drinks may be linked to a condition known as erosive tooth wear, in which acids eat away the tooth's smooth hard enamel coating and trickle into the bonelike material underneath, causing the tooth to soften and weaken. The condition affects one in 15 Americans and can result in severe tooth damage and even tooth loss if left untreated.
"This is the first time that the citric acid in sports drinks has been linked to erosive tooth wear," said Dr. Mark Wolff, Professor and Chairman of the Department of Cariology & Comprehensive Care at New York University College of Dentistry, who led the study. The findings were presented today at the annual meeting of the International Association for Dental Research in Miami.
Dr. Wolff's research team cut in half cow teeth, which were used for the study because of their close resemblance to human teeth. They immersed one half of the specimens in a sports drink, the other half in water, then compared the two halves and discovered that the one exposed to the sports drink displayed a significant amount of erosion and softening.
"Five teeth were immersed in each drink for 75 to 90 minutes to simulate the effects of sipping on sports drinks over the course of the day," Dr. Wolff said. The researchers evaluated the effects of a range of top-selling sports drinks on the cow teeth.
According to Dr. Wolff, brushing teeth immediately after consuming a sports drink can compound the problem of tooth erosion, because softened enamel is very susceptible to the abrasive properties of toothpaste.
"To prevent tooth erosion, consume sports drinks in moderation, and wait at least 30 minutes before brushing your teeth, to allow softened enamel to re-harden," Dr. Wolff advised. "If you frequently consume sports drinks, ask your dentist if you should use an acid-neutralizing remineralizing toothpaste to help re-harden soft enamel."
Thursday, April 2, 2009
Salivary diagnostics comes of age
Salivary diagnostics has come of age. In a mere six years, research supported by the National Institute of Dental and Craniofacial Research (NIDCR) has sprung to the forefront of basic, translational, and clinical research. In a scientific session on "Oral Fluid Diagnostics", to be held during the 87th General Session of the International Association for Dental Research, convening today at the Miami Beach Convention Center, researchers will showcase a remarkable spectrum of research outcomes that expands the clinical applications of saliva based on 'diagnostic toolboxes', as well as establishing foundational mechanistic insights into salivary diagnostics.
Three papers will highlight the scientific and translational values of three diagnostic toolboxes (proteins, DNA, and RNA) in saliva. One research team identified 36 novel phosphoproteins in parotid saliva. This elegantly established the systemic phosphoproteome documentation technology, providing a powerful tool to evaluate health vs. disease states of oral and systemic disease. Another group explores the methylation status of genomic DNA contents of 807 cancer-associated genes in the saliva of oral cancer patients. Subpanels of these differentially methylated genes were able to discriminate oral cancer subjects with a specificity of 83-100% and a sensitivity of 62-77%, providing proof-of-concept data that differential methylation analysis of specific cellular genes in saliva can be used to detect oral cancer. A third diagnostic alphabet, the salivary transcriptome, was discovered to exist in saliva encapsulated in a lipid bilayer entity known as the exosome. This is a significant finding, since it provides the long-missing scientific rationale as to why endogenous salivary mRNA is unusually stable, firmly providing the scientific rationale for the translational utilization of the salivary transcriptome for biomarker studies.
This session will also feature a paper that highlights a translational and clinical application of salivary biomarkers for detecting patients with acute coronary syndrome (ACS). Of interest is that discriminatory salivary biomarkers for ACS are gender- and fluid-specific (stimulated vs. unstimulated). The potential use of saliva, rather than blood, for ACS detection presents clear clinical advantages.
Last, there will be a paper demonstrating the mechanistic insights into the value of salivary diagnostics for systemic disease detection. In rodent tumor transplantation models of melanoma and lung cancer, tumor-associative saliva biomarker profiles were observed. A systemic disease-induced salivary biomarker fingerprint is therefore validated. The working model proposed is that tumors, like endocrine organs, produce hormones, lymphokines, and cytokines, which will traverse through the vasculature and reach a distal organ to exert biological actions. When reaching the salivary glands, these hormones/lymphokines/cytokines will lead to transcriptional profile changes and ectopic protein translation, which will be secreted into saliva as tumor-associated surrogate biomarkers. This is the first mechanistic demonstration of a profile connection between systemic disease and salivary biomarkers.
Three papers will highlight the scientific and translational values of three diagnostic toolboxes (proteins, DNA, and RNA) in saliva. One research team identified 36 novel phosphoproteins in parotid saliva. This elegantly established the systemic phosphoproteome documentation technology, providing a powerful tool to evaluate health vs. disease states of oral and systemic disease. Another group explores the methylation status of genomic DNA contents of 807 cancer-associated genes in the saliva of oral cancer patients. Subpanels of these differentially methylated genes were able to discriminate oral cancer subjects with a specificity of 83-100% and a sensitivity of 62-77%, providing proof-of-concept data that differential methylation analysis of specific cellular genes in saliva can be used to detect oral cancer. A third diagnostic alphabet, the salivary transcriptome, was discovered to exist in saliva encapsulated in a lipid bilayer entity known as the exosome. This is a significant finding, since it provides the long-missing scientific rationale as to why endogenous salivary mRNA is unusually stable, firmly providing the scientific rationale for the translational utilization of the salivary transcriptome for biomarker studies.
This session will also feature a paper that highlights a translational and clinical application of salivary biomarkers for detecting patients with acute coronary syndrome (ACS). Of interest is that discriminatory salivary biomarkers for ACS are gender- and fluid-specific (stimulated vs. unstimulated). The potential use of saliva, rather than blood, for ACS detection presents clear clinical advantages.
Last, there will be a paper demonstrating the mechanistic insights into the value of salivary diagnostics for systemic disease detection. In rodent tumor transplantation models of melanoma and lung cancer, tumor-associative saliva biomarker profiles were observed. A systemic disease-induced salivary biomarker fingerprint is therefore validated. The working model proposed is that tumors, like endocrine organs, produce hormones, lymphokines, and cytokines, which will traverse through the vasculature and reach a distal organ to exert biological actions. When reaching the salivary glands, these hormones/lymphokines/cytokines will lead to transcriptional profile changes and ectopic protein translation, which will be secreted into saliva as tumor-associated surrogate biomarkers. This is the first mechanistic demonstration of a profile connection between systemic disease and salivary biomarkers.
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