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.'

Gum Offers Caffeine Boost

Wrigley is launching a new chewing gum called Alert Energy Caffeine Gum which offers a boost of caffeine. The new product is aimed at consumers between the ages of 25 and 49 who may have quit their habit of chewing gum when they were younger, while tapping into the market of energy products - a rapid-growth market. The caffeinated gum is intended for adults who "want a portable product that lets them control their caffeine intake", the company said. "Alert" contains 40 milligrams of caffeine - the same amount of caffeine as about a half a cup of coffee or a 16-ounce soda. Wrigley is the largest producer of gum worldwide, and also makes brands such as:•Big Red •Juicy Fruit •Doublemint Energy drinks and other related products have been more popular on the market in recent years, despite the fact that some experts claim they are bad for people's health. A small US study demonstrated an association between energy drinks and high blood pressure or heart disease risk, and one report indicated that the drinks can cause irreversible damage to teeth. However, the products are still increasingly popular, and because of this, increasing gum sales has been a primary goal for the company in recent years. Wrigley plans to launch Alert in some stores in April with a full roll-out targeted for summer. Alert's suggested retail cost is $2.99 for an eight-pack. The product will be sold in both fruit and mint flavors. Casey Keller, president of the North America division of Wrigley, said: "The taste expectations are different for someone who wants to chew gum for energy than for someone who chews gum for flavor. If you come at this as a piece of gum that you chew for enjoyment it's not going to deliver on that. What we found from energy [drink] consumers is that they're used to this taste. It's symbolic of efficacy." Alert packs will, of course, list the ingredients and include warning labels about caffeine intake. It will not be intended for minors, according to Wm. Wrigley Jr. Co. Wrigley spokeswoman Jennifer Luth added: "There's nothing we can do to prevent people from selling it to children. But we've done everything we can so it's not a product for children or teens. It is absolutely designed for adults who are already using caffeine for energy."

Tooth Loss More Likely In Postmenopausal Women

Postmenopausal women who have smoked are at much higher risk of losing their teeth than women who never smoked, according to a new study published and featured on the cover of the Journal of the American Dental Association by researchers at the University at Buffalo. The study involved 1,106 women who participated in the Buffalo OsteoPerio Study, an offshoot of the Women's Health Initiative, (WHI), the largest clinical trial and observational study ever undertaken in the U.S., involving more than 162,000 women across the nation, including nearly 4,000 in Buffalo. The UB study is the first to examine comprehensive smoking histories for participants that allowed the researchers to unravel some of the causes behind tooth loss in postmenopausal women who smoked. Smoking has long been associated with tooth loss, but postmenopausal women, in particular, experience more tooth loss than their male counterparts. "Regardless of having better oral health practices, such as brushing and flossing, and visiting the dentist more frequently, postmenopausal women in general tend to experience more tooth loss than men of the same age," says Xiaodan (pronounced Shee-ao-dan) Mai, a doctoral student in epidemiology in the UB Department of Social and Preventive Medicine in the School of Public Health and Health Professions. "We were interested in smoking as a variable that might be important." While fewer adults lose their teeth now than in past decades, tooth loss is associated with poor health outcomes, including stroke, cancer, rheumatoid arthritis and diabetes. In the UB study, heavy smokers -- defined as those who had at least 26 pack-years of smoking, or the equivalent of having smoked a pack a day for 26 years -- were nearly twice as likely to report having experienced tooth loss overall and more than six times as likely to have experienced tooth loss due to periodontal disease, compared to those who never smoked. Participants provided information to researchers using a detailed questionnaire covering smoking history. Each participant also underwent a comprehensive oral examination and reported to the dental examiners reasons for each tooth lost. In some cases, the patient's dental records also were reviewed. "We found that heavy smokers had significantly higher odds of experiencing tooth loss due to periodontal disease than those who never smoked," explains Mai. "We also found that the more women smoked, the more likely they experienced tooth loss as a result of periodontal disease." On the other hand, they found that smoking was a less important factor in tooth loss due to caries. That's an important distinction, says Mai. "Periodontal disease is a chronic, inflammatory condition that may be related to the development of cancer," she explains. The paper notes that cigarette smoke may accelerate periodontal disease and that other studies suggest that chemicals found in smoke may favor plaque-forming bacteria that could reduce the ability of saliva to be antioxidative. Nicotine also has been shown to reduce bone density and bone mineral factors while estrogen hormones have been found to be lower among women who smoke. Mai is now interested in pursuing research that could determine whether smokers with periodontal disease are at even greater risk for certain cancers than smokers without periodontal disease. "Tooth loss due to periodontal disease is a prevalent condition among postmenopausal women that severely impacts their dietary intake, aesthetics, and overall quality of life," says Mai. "Women now have yet another, very tangible reason for quitting smoking."