Novacain And Missing Wisdom Teeth

Researchers from Tufts University School of Dental Medicine have discovered a statistical association between the injection of local dental anesthesia given to children ages two to six and evidence of missing lower wisdom teeth. The results of this epidemiological study, published in the April issue of The Journal of the American Dental Association, suggest that injecting anesthesia into the gums of young children may interrupt the development of the lower wisdom tooth. "It is intriguing to think that something as routine as local anesthesia could stop wisdom teeth from developing. This is the first study in humans showing an association between a routinely- administered, minimally-invasive clinical procedure and arrested third molar growth," said corresponding author, Anthony R. Silvestri, D.M.D., clinical professor in the department of prosthodontics and operative dentistry at Tufts University School of Dental Medicine. Wisdom teeth are potentially vulnerable to injury because their development - unlike all other teeth - does not begin until well after birth. Between two and six years of age, wisdom tooth (third molar) buds begin to develop in the back four corners of the mouth, and typically emerge in the late teens or early adulthood. Not everyone develops wisdom teeth, but for those who do, the teeth often become impacted or problematic. The American Association of Oral and Maxillofacial Surgeons reports that nine out of 10 people will have at least one impacted wisdom tooth, which can cause bad breath, pain, and/or infection. For this reason, many dentists recommend surgery to remove wisdom teeth to prevent disease or infection. A developing wisdom tooth, called a bud, is vulnerable to injury for a relatively long time because it is tiny, not covered by bone, and only covered by a thin layer of soft tissue. When a tooth bud first forms, it is no bigger than the diameter of the dental needle itself. The soft tissue surrounding the budding tooth is close to where a needle penetrates when routine dental anesthesia is injected in the lower jaw, for example when treating cavities. Using the Tufts digital dental record system, the researchers identified records of patients who had received treatment in the Tufts pediatric dental clinic between the ages of two and six and who also had a dental x-ray taken three or more years after initial treatment in the clinic. They eliminated records with confounding factors, such as delayed dental development, and analyzed a total of 439 sites where wisdom teeth could develop in the lower jaw, from 220 patient records. Group one, the control group (376 sites), contained x-rays of patients who had not received anesthesia on the lower jaw where wisdom teeth could develop. Group two, the comparison group (63 sites), contained x-rays from patients who had received anesthesia. In the control group, 1.9% of the sites did not have x-ray evidence of wisdom tooth buds. In contrast, 7.9% of the sites in the comparison group - those who had received anesthesia - did not have tooth buds. The comparison group was 4.35 times more likely to have missing wisdom tooth buds than the control group. "The incidence of missing wisdom teeth was significantly higher in the group that had received dental anesthesia; statistical evidence suggests that this did not happen by chance alone. We hope our findings stimulate research using larger sample sizes and longer periods of observation to confirm our findings and help better understand how wisdom teeth can be stopped from developing," Silvestri continued. "Dentists have been giving local anesthesia to children for nearly 100 years and may have been preventing wisdom teeth from forming without even knowing it. Our findings give hope that a procedure preventing third molar growth can be developed." Silvestri has previously published preliminary research on third molar tooth development, showing that third molars can be stopped from developing when non- or minimally-invasive techniques are applied to tooth buds.

Breath Test Reveals Alot

In The Endocrine Society's Journal of Clinical Endocrinology & Metabolism 26 March online issue, researchers from the Cedars-Sinai Medical Center in Los Angeles report how people with high levels of both hydrogen and methane in their breath are more likely to have a higher body mass index (BMI) and a higher proportion of body fat. They suggest the presence of certain bacteria in the gut causes it to extract more calories from food, adding to weight gain. Lead author Ruchi Mathur, director of the Diabetes Outpatient Treatment and Education Center in the Division of Endocrinology at Cedars-Sinai, says in a statement: "This is the first large-scale human study to show an association between gas production and body weight," adding that "this could prove to be another important factor in understanding one of the many causes of obesity." Mathur and her colleagues tested the exhaled breath of 792 people and found four patterns: normal breath, or breath containing higher levels of methane, higher levels of hydrogen, or higher levels of both gases. And the participants' whose breath had higher levels of both methane and hydrogen were the ones significantly more likely to have a higher BMI and higher proportions of body fat. A gut bacterium called Methanobrevibacter smithii is responsible for most of the methane produced in the human gut. Mathur says that usually bacteria like M. smithii are beneficial because they help extract energy and nutrients from food. But if there is too much M. smithii, it alters the energy balance so as to make the person more likely to put on weight. It does not do this directly, but by the effect it has on neighbouring bacteria, the researchers suggest. M. smithii produces methane by scavenging hydrogen from other microrganisms. The researchers propose that this gives hydrogen- producing bacteria a boost, making them more efficient so as to extract more nutrients and calories from food. It is this, which eventually leads to weight gain, says Mathur. Mathur is also working on another study that seeks to confirm the link between M. smithii, obesity and pre-diabetes. On that study the participants are given a dose of antibiotics to wipe out the bacterium so that researchers can compare how efficiently they digest food when they have the bacterium in their gut to when they do not. Mathur says we are only "beginning to understand the incredibly complex communities that live inside of us". "If we can understand how they affect our metabolism, we may be able to work with these microscopic communities to positively impact our health," she adds. Several examples of the surprising ways gut bacteria influence the human body have emerged in recent years. For instance, an animal study published in the Journal of Proteome Research in February 2012, suggests that gut bacteria may play a role in obesity by slowing down the activity of energy-burning brown fat. And in a study published in February 2013, US scientists describe how gut bacteria form part of a complex system that maintains the body's blood pressure.

Sleep Apena and Children

Obstructive sleep apnea, a common type of sleep-disordered breathing (SDB), has been linked to elevated rates of ADHD-like behavioral issues in kids, in addition to learning and adaptive problems. The findings were published in the journal Sleep and came about after a five-year study which analyzed data from a longitudinal cohort called the Tucson Children's Assessment of Sleep Apnea Study (TuCASA). The study assessed Caucasian and Hispanic kids ranging in age from 6 to 11 years to measure the incidence and prevalence of SDB and its consequences on neurobehavioral functioning. Michelle Perfect, PhD, the study's lead author and assistant professor in the school psychology program in the department of disability and psychoeducational studies at the University of Arizona in Tucson, said: "This study provides some helpful information for medical professionals consulting with parents about treatment options for children with SDB that, although it may remit, there are considerable behavioral risks associated with continued SDB. School personnel should also consider the possibility that SDB contributes to difficulties with hyperactivity, learning and behavioral and emotional deregulation in the classroom." The study consisted of 263 kids who participated in a sleep study and a neurobehavioral test of assessments which included youth and parent-documented rating scales. The outcomes revealed that 23 kids had incident sleep apnea that developed during the trial period, while 21 kids had persistent sleep apnea for the entire length of the study. An additional 41 children who started out with sleep apnea stopped having breathing issues during sleep when examined at the five-year follow-up. In children with incident sleep apnea, the risk of having behavioral issues was four to five times higher. In kids with persistent sleep apnea, that risk was six times higher. Compared with children who never experienced SDB, those with sleep apnea were more inclined to have parent-documented issues in the areas of: • attention • disruptive behaviors • hyperactivity • social competency • self-care • communication Kids with persistent sleep apnea were shown to be seven times more likely to have parent-documented learning issues and three times more likely to earn grades of C or under. Research reported at the 24th annual meeting of the Associated Professional Sleep Societies in 2010, revealed that the academic grades of children with sleep apnea are worse than students who do not have sleep-related breathing problems. The authors noted that this was the first sleep-related study to utilize a standardized survey to measure adaptive functioning in normal youths with and without SDB.

Flouride in Drinking Water

A new study conducted by researchers at the University of North Carolina at Chapel Hill and the University of Adelaide, Australia, has produced the strongest evidence yet that fluoride in drinking water provides dental health benefits to adults, even those who had not received fluoridated drinking water as children. In the first population-level study of its kind, the study shows that fluoridated drinking water prevents tooth decay for all adults regardless of age, and whether or not they consumed fluoridated water during childhood. Led by UNC School of Dentistry faculty member Gary Slade, the study adds a new dimension to evidence regarding dental health benefits of fluoridation. "It was once thought that fluoridated drinking water only benefited children who consumed it from birth," explained Slade, who is John W. Stamm Distinguished Professor and director of the oral epidemiology Ph.D. program at UNC. "Now we show that fluoridated water reduces tooth decay in adults, even if they start drinking it after childhood. In public health terms, it means that more people benefit from water fluoridation than previously thought." The researchers analyzed national survey data from 3,779 adults aged 15 and older selected at random from the Australian population between 2004 and 2006. Survey examiners measured levels of decay and study participants reported where they lived since 1964. The residential histories of study participants were matched to information about fluoride levels in community water supplies. The researchers then determined the percentage of each participant's lifetime in which the public water supply was fluoridated. The results, published online in the Journal of Dental Research, show that adults who spent more than 75 percent of their lifetime living in fluoridated communities had significantly less tooth decay (up to 30 percent less) when compared to adults who had lived less that 25 percent of their lifetime in such communities. "At this time, when several Australian cities are considering fluoridation, we should point out that the evidence is stacked in favor of long-term exposure to fluoride in drinking water," said Kaye Roberts-Thomson, a co-author of the study. "It really does have a significant dental health benefit."

Mercury Fillings and Your Body

A common test used to determine mercury exposure from dental amalgam fillings may significantly overestimate the amount of the toxic metal released from fillings, according to University of Michigan researchers. Scientists agree that dental amalgam fillings slowly release mercury vapor into the mouth. But both the amount of mercury released and the question of whether this exposure presents a significant health risk remain controversial. Public health studies often make the assumption that mercury in urine (which is composed mostly of inorganic mercury) can be used to estimate exposure to mercury vapor from amalgam fillings. These same studies often use mercury in hair (which is composed mostly of organic mercury) to estimate exposure to organic mercury from a person's diet. But a U-M study that measured mercury isotopes in the hair and urine from 12 Michigan dentists found that their urine contained a mix of mercury from two sources: the consumption of fish containing organic mercury and inorganic mercury vapor from the dentists' own amalgam fillings. "These results challenge the common assumption that mercury in urine is entirely derived from inhaled mercury vapor," said Laura Sherman, a postdoctoral research fellow in the Department of Earth and Environmental Sciences and lead author of a paper in the journal Environmental Science & Technology. A final version of the paper has been published online. "These data suggest that in populations that eat fish but lack occupational exposure to mercury vapor, mercury concentrations in urine may overestimate exposure to mercury vapor from dental amalgams. This is an important consideration for studies seeking to determine the health risks of mercury vapor inhalation from dental amalgams," said U-M biogeochemist Joel D. Blum, a co-author of the paper and a professor in the Department of Earth and Environmental Sciences. The study by Sherman, Blum and their colleagues demonstrates that mercury isotopes can be used to more accurately assess human exposure to the metal - and the related health risks - than traditional measurements of mercury concentrations in hair and urine samples. Specifically, isotopes provide a novel chemical tracer that can be used to "fingerprint" both organic mercury from fish and inorganic mercury vapor from dental amalgams. Mercury is a naturally occurring element, but more than 2,000 tons are emitted into the atmosphere each year from human-generated sources such as coal-fired power plants, small-scale gold-mining operations, metals and cement production, incineration and caustic soda production. This mercury is deposited onto land and into water, where micro-organisms convert some of it to methylmercury, a highly toxic organic form that builds up in fish and the animals that eat them, including humans. Effects on humans include damage to the central nervous system, heart and immune system. The developing brains of fetuses and young children are especially vulnerable. Inorganic mercury can also cause central nervous system and kidney damage. Exposure to inorganic mercury occurs primarily through the inhalation of elemental mercury vapor. Industrial workers and gold miners can be at risk, as well as dentists who install mercury amalgam fillings - though dentists have increasingly switched to resin-based composite fillings and restorations in recent years. About 80 percent of inhaled mercury vapor is absorbed into the bloodstream in the lungs and transported to the kidneys, where it is excreted in urine. Because the mercury found in urine is almost entirely inorganic, total mercury concentrations in urine are commonly used as an indicator,

Dental Health May Predict Cardiovascular Risk

Poor dental health, especially tooth loss, is associated with several established cardiovascular risk factors, including diabetes, smoking, blood pressure, obesity and other novel risk factors, according to research being presented at the American College of Cardiology's 62nd Annual Scientific Session. Although several studies have proposed a link between periodontal disease and coronary heart disease, knowledge about periodontal disease in patients with established heart disease is lacking. Researchers investigated the prevalence of self-reported tooth loss and occurrence of gum bleeds, as surrogate markers of periodontal disease, and their relation to cardiovascular risk factors in high-risk patients with coronary heart disease participating in the ongoing STABILITY study, a global clinical trial evaluating the anti-atherosclerosis drug darapladib. At the start of the study, 15,828 study participants from 39 countries reported their remaining number of teeth, categorized as none, 1-14, 15-19, 20-25 or 26-32, and frequency of gum bleeds, never/rarely, sometimes, often or always. Data on cardiovascular risk factors were also obtained, and statistical analyses were performed, adjusting for age, smoking, diabetes and education. Approximately 40 percent of participants had fewer than 15 teeth and 16 percent had no teeth; 25 percent of subjects reported gum bleeds. For every decrease in number of teeth, researchers observed increasing levels of Lp-PLA2, an enzyme that increases inflammation and promotes hardening of the arteries, as well as an increase in other cardiac risk markers including LDL or "bad" cholesterol, blood sugar, blood pressure and waist circumference. Participants with fewer teeth also had higher probability of having diabetes, with the odds increasing by 11 percent for every decrease in number of teeth category. Greater loss of teeth was also associated with being a current or former smoker compared to being a non-smoker and having a lower education. Gum bleeds were associated with higher levels of bad cholesterol and blood pressure, as well as a greater likelihood of being a non-smoker and having a higher education. Researchers were surprised by the large proportion of patients with no or very few teeth and had expected somewhat stronger associations between gum bleeding and cardiovascular risk factors. "Gum bleeding is an early manifestation of periodontal disease, whereas tooth loss represents the final stage," said Ola Vedin, MD, from the Department of Medical Sciences at Uppsala University in Sweden and the study's lead investigator. "Therefore, one theory is that patients with gum bleeding but little or no tooth loss have had less and shorter exposure to the processes of periodontitis and have thus developed fewer complications." Dr. Vedin cautions that researchers are still unclear about what is behind the association between tooth loss, gum health and heart health. "Whether periodontal disease actually causes coronary heart disease remains to be shown. It could be that the two conditions share common risk factors independently," Dr. Vedin said. "Those who believe that a causal relationship exists propose several theories, including systemic inflammation, the presence of bacteria in the blood from infected teeth and bacteria invading coronary plaques." According to Dr. Vedin, additional studies are needed to unravel the potential for periodontal health to be a useful risk marker for heart disease. If future research can confirm a causal relationship, dentists could play an important role in cardiovascular risk assessment.

New Method To Replace Teeth With A Person's Own Gum Cells

Scientists have developed a new method of replacing missing teeth with a bioengineered material generated from a person's own gum cells. Current implant-based methods of whole tooth replacement fail to reproduce a natural root structure and as a consequence of the friction from eating and other jaw movement, loss of jaw bone can occur around the implant. The research is led by Professor Paul Sharpe, an expert in craniofacial development and stem cell biology at King's College London and published in the Journal of Dental Research. Research towards achieving the aim of producing bioengineered teeth - bioteeth - has largely focused on the generation of immature teeth (teeth primordia) that mimic those in the embryo that can be transplanted as small cell 'pellets' into the adult jaw to develop into functional teeth. Remarkably, despite the very different environments, embryonic teeth primordia can develop normally in the adult mouth and thus if suitable cells can be identified that can be combined in such a way to produce an immature tooth, there is a realistic prospect bioteeth can become a clinical reality. Subsequent studies have largely focused on the use of embryonic cells and although it is clear that embryonic tooth primordia cells can readily form immature teeth following dissociation into single cell populations and subsequent recombination, such cell sources are impractical to use in a general therapy. Professor Sharpe says: 'What is required is the identification of adult sources of human epithelial and mesenchymal cells that can be obtained in sufficient numbers to make biotooth formation a viable alternative to dental implants.' In this new work, the researchers isolated adult human gum tissue from patients at the Dental Institute at King's College London, grew more of it in the lab, and then combined it with the cells of mice that form teeth. By transplanting this combination of cells into mice the researchers were able to grow hybrid human/mouse teeth containing dentine and enamel, as well as viable roots. Professor Sharpe concludes: 'Epithelial cells derived from adult human gum tissue are capable of responding to tooth inducing signals from embryonic tooth mesenchyme in an appropriate way to contribute to tooth crown and root formation and give rise to relevant differentiated cell types, following in vitro culture. 'These easily accessible epithelial cells are thus a realistic source for consideration in human biotooth formation. The next major challenge is to identify a way to culture adult human mesenchymal cells to be tooth-inducing, as at the moment we can only make embryonic mesenchymal cells do this.'