Wednesday, December 22, 2010

A New Method Is Developed For Predicting Shade Improvement After Teeth Bleaching

This is the first time that scientists manage to predict the outcome of bleaching treatments, which will certainly have an important impact on these treatments, which are becoming frequent

Researchers at the University of Granada have developed a new method for predicting the precise shade that a bleaching treatment will bring about for a patient’s teeth. What is innovative about this method is that it allows researchers to successfully predict the outcome of a bleaching treatment, which will have a significant impact on such treatments, which are becoming more frequent.

At present, dental offices routinely employ carbomide peroxide bleaching agents for tooth discoloration. As bleaching treatments have soft side effects –all of them temporary and mild– and are relatively cost-effective, they have become very popular.

While bleaching treatments have been long applied, one of its main problems has been the inability to predict the outcome of the process. This means that, so far, dentists have been unable to predict the results for patients’ teeth. This means that dental physicians could not inform their patients on the shade improvement that the treatment would bring about, which was a limitation to the therapy.

The study was conducted by Janiley Santana Díaz, at the Department of Stomatology of the University of Granada and was coordinated by professors Rosa Mª Pulgar Encinas, Mª Del Mar Pérez Gómez and Luis Javier Herrera Maldonado. Using a fuzzy rule system, scientists had a first approach to the shade improvement that teeth can get after undergoing a 20% carbamide peroxide treatment (Opalescence® PF 20%, Ultradent) two hours a day for two weeks.


For the purpose of this study, authors took a sample of 53 subjects that subsequently underwent a teeth bleaching treatment. Before the bleaching treatment, participants answered a questionnaire on their eating habits so that scientists analyzed whether such habits had any impact on the prediction models. The researchers found that eating habits are not relevant to such models, so these factors where not considered in the study.

To illustrate the shade change expected after the teeth bleaching treatment, the University of Granada researchers designed a fuzzy system that allows to associate these instrumental measures to the commercial shade guides typically used at dental offices to identify the before-and-after tooth color.

Such association allows to establish a series of objective guidelines that, once the before-tooth color is identified with the closest shade of the guide, will allow both dentist and patient to predict the color that the teeth will get after the treatment.

All in all, researchers warn that, in the long term and given the limitation of any clinical trial, a wider range of patients and initial tooth colors would be required to obtain a more precise fuzzy system.

Thursday, December 16, 2010

The protective shield fluoride forms on teeth is up to 100 times thinner than previously believed


In a study that the authors describe as lending credence to the idiom, "by the skin of your teeth," scientists are reporting that the protective shield fluoride forms on teeth is up to 100 times thinner than previously believed. It raises questions about how this renowned cavity-fighter really works and could lead to better ways of protecting teeth from decay, the scientists suggest. Their study appears in ACS' journal Langmuir.

Frank Müller and colleagues point out that tooth decay is a major public health problem worldwide. In the United States alone, consumers spend more than $50 billion each year on the treatment of cavities. The fluoride in some toothpaste, mouthwash and municipal drinking water is one of the most effective ways to prevent decay. Scientists long have known that fluoride makes enamel — the hard white substance covering the surface of teeth — more resistant to decay. Some thought that fluoride simply changed the main mineral in enamel, hydroxyapatite, into a more-decay resistant material called fluorapatite.

The new research found that the fluorapatite layer formed in this way is only 6 nanometers thick. It would take almost 10,000 such layers to span the width of a human hair. That's at least 10 times thinner than previous studies indicated. The scientists question whether a layer so thin, which is quickly worn away by ordinary chewing, really can shield teeth from decay, or whether fluoride has some other unrecognized effect on tooth enamel. They are launching a new study in search of an answer.

ARTICLE: "Elemental Depth Profiling of Fluoridated Hydroxyapatite: Saving Your Dentition by the Skin of Your Teeth?"

Tuesday, December 14, 2010

University of Maryland Dental School Stepping Up Ergonomics Instruction


In response to a high prevalence of neck and back pain among working dentists and dental hygienists, the dean of the University of Maryland Dental School Christian S. Stohler, DMD, DrMedDent, has launched an initiative to bring renewed attention to ergonomics into dental education.

Starting with the current semester, every incoming student must take the School’s course “Ergonomics in Dentistry,” before he or she can practice simulations or live-patient dental work. The School wants to be the place where dentists and dental hygienists learn to practice ergonomically correct practices, says Stohler.

“Three out of every five dentists live with the pain,” due to years of practicing with poor posture and other unwise positioning, guest lecturer Lance Rucker, DDS, director of clinical ergonomics and simulation at the University of British Columbia, told this year’s incoming class.

Stohler recruited Rucker as the world’s leading authority on dentistry ergonomics to kick off its course with a lecture and workshops. He greeted the new students with, “If you want to be a healthy, well-postured individual, statistically you have chosen the wrong profession. However, you do have a choice.”

Studies in the U.S. and in Canada over the past 37 years have underscored the need for dentists to adopt more ergonomically correct equipment and positioning, Rucker explained. He said that two-thirds of dentists lose days of practice each year by avoidable muscular skeletal pain.

Retired professor Michael Belenky, DDS, MPH, has taught what he refers to as human center ergonomics at the School for many years,” We first ask a student to identify how he or she would like to stand or sit for optimal visual and physical comfort and effectiveness,” says Belenky “Many dentists eventually need years of physical therapy, go to a chiropractor or even have surgery, but seldom do you hear about the need for preventive solutions, the etiology of the problem.”

Norman Bartner, DDS, a clinical assistant professor who leads the upgraded course, (above with students) says, “We are widely recognized as the no. 1 dental school in the country. Now we want to be known as the School that graduates students with the longest careers, greatest earning capacity, and enjoy the most leisure time because they are healthy.” He added, “This should increase alumni financial support for the School as well.”

Bartner and Belenky have created an instructional video that begins with dentists who have been forced from the profession with musculo-skeletal problems, due to poor ergonomic working conditions.

Bartner says, “I don’t want students developing musculo-skeletal problems from chronic stress on the neck, shoulder, high back, and low back. We start all the dental students off with knowing the proper posture as a dentist for avoiding such career-limiting problems.”

Monday, December 13, 2010

For Your Teeth, Thanksgiving Dinner Is a Real Food Fight


If you're lucky, it will all be kisses and hugs around the Thanksgiving dinner table, with friends and family near and dear gathered about, and puppies at your feet waiting for table scraps.

But peace won't reign within the confines of the oral cavity, where Streptococcus mutans and other harmful bacteria will await their own holiday feast. Your meal will enable S. mutans to launch one of its biggest assaults of the year on your tooth enamel.

New work by dental researchers at the University of Rochester Medical Center brings both good and bad news. While bacterial forces in your mouth will exploit your delectables in newly discovered ways, some foods common at the holiday dinner table -- like the cranberry and even wine -- offer new leads in the effort to stop tooth decay.

The Thanksgiving Day battle for oral health hinges on microbes like S. mutans. Most cookies, pies and the like contain mountains of sugar, but it's not the sugar itself that causes tooth decay. Rather, S. mutans and other bacteria in our mouths -- billions of individual microbes all waiting for their next snack -- feast on the sugars, stick on your teeth and then churn out acid that eats away at tooth enamel.

At the front lines is Hyun "Michel" Koo, D.D.S, Ph.D., a dentist turned food scientist and microbiologist who is both exploring the destructive power of S. mutans and scouring foods and natural substances to harness their ability to prevent cavities. With every portion of bad news he delivers about cavities comes good news about compounds that may help prevent tooth decay.

"Natural substances offer tremendous possibilities for stopping tooth decay," said Koo, who earlier this year received a $1.6 million from the National Institute of Dental and Craniofacial Research to conduct his research. "Our time spent in the laboratory is aimed at harnessing the potential of some of these compounds, perhaps eventually incorporating them into a toothpaste or mouth rinse to stop dental decay."

Good news at the dinner table

Koo is hot on the trail of the cranberry as a potential ally in the fight against S. mutans, which is a threat to our teeth primarily because of its ability to form plaque. What appears to us as sticky white gunk along our teeth is actually a formidable fortress of molecules known as glucans -- building blocks of plaque, stacked like bricks in a wall, rife with bacteria. It's a gunky fortress that covers the tooth and gives bacteria a safe haven to munch on sugar, thrive, and churn out acid.

Koo has discovered that compounds within the cranberry disrupt enzymes known as glucosyltransferases that bacteria use to build glucans. Without its glucans, S. mutans and other bad bacteria in plaque becomes vulnerable.

Together with Nicholi Vorsa, Ph.D., director of the Philip E. Marucci Center for Blueberry and Cranberry Research and Extension at Rutgers University, Koo is working to isolate the compounds within the cranberry that are most protective. The pair has identified molecules known as A-type proanthocyanidins as having potential to reduce cavities dramatically. Earlier this year in the journal Caries Research, the team reported that when the molecules were applied, glucan and acid production by S. mutans was reduced by up to 70 percent, and cavity formation in rats was slashed by up to 45 percent.

"Maintaining the natural balance of resident flora in the oral cavity is important for keeping opportunistic pathogens in check," said Koo, a researcher in the Center for Oral Biology and an associate professor in the Eastman Institute for Oral Health and the Department of Microbiology and Immunology. "These molecules don't outright kill S. mutans. Instead, they disrupt the two most harmful actions of this pathogenic organism, acid production and glucan production."

More good news

More good news comes from that delicious glass of wine, or at least the waste in its wake. With funding from the U.S. Department of Agriculture, Koo began a research project with Olga I. Padilla-Zakour, Ph.D., associate professor of Food Processing at the New York Agricultural Experiment Station of Cornell University. They found that the abundant waste from the red-wine-making process -- materials such as fermented seeds and skins collectively known as pomace that are cast away after grapes are pressed -- contains compounds that fight S. mutans. In particular, some polyphenols can inhibit the activity of S. mutans' crucial enzymes by as much as 85 percent and also reduce the amount of acid the bacteria produce.

And the bad news

Last month in PloS One, Koo showed that S. mutans is even more powerful than scientists have realized, responding readily to changing environmental conditions in the presence of starch and sucrose to thrive in the mouth.

In work led by Marlise Klein, D.D.S., Ph.D., research assistant professor, Koo's team analyzed the activity of more than 300 genes in S. mutans under changing conditions. The team found that certain key proteins boost their activity dramatically in the presence not only of sugar but also complex carbohydrates derived from starch digestion. Once the body's own amylase enzymes naturally present in saliva break down starches, S. mutans kicks its glucan-forming machinery into high gear.

"The new research shows how two pillars of the modern diet, starch and sugar, can work cooperatively to bring about tooth decay," said Koo. "A cookie, sugar-covered doughnut, or a piece of pie filled with both sugar and starch provide the perfect recipe for the bacteria that destroy teeth."

Even when the amount of sugar was slashed in half, certain genes central to the ability of S. mutans to create its formidable glucan fortress boosted their activity five-fold in the presence of starch-derived carbohydrates. That enabled the bacteria to create plaque that is hardier, stickier, and capable of producing more acid than plaque created without significant starch present.

On Thanksgiving Day ……

Koo notes people shouldn't simply eat more cranberry sauce or drink more wine to try to prevent cavities. His work is aimed at identifying and then exploiting specific compounds that give the benefit without, for instance, the high levels of acidity or the added sugar that cranberry products might include. Rather, at this point, everything your dentist keeps telling you remains the best advice to prevent cavities.

"On Thanksgiving Day, like any day, brush your teeth, avoid foods filled with sugars as best you can, and don't snack often -- and if you do, brush your teeth again," said Koo. "Consider using a mouth rinse, get some fluoride in there -- and be sure to see a dentist regularly."

Friday, December 10, 2010

Scientists and Citizens Opposed to Mercury Fillings Urge FDA Panel to Restrict Amalgam PR Newswire


FDA Device Division, still concerned about mercury toxicity in American dentistry, is convening yet another professional panel review regarding safety issues. A nationwide convergence of scientists, dental and medical professionals, lead by the International Academy of Oral Medicine and Toxicology (IAOMT) are provoking new challenges to the Food and Drug Administration's (FDA) July'09 "no risk" classification of mercury fillings . The Holiday Inn, Gaithersburg MD is the site of FDA's Dental Products Panel meeting December 14 & 15 where scientific and public testimony will be presented.

The use of mercury fillings, deceptively called "silver" by the dental profession, has been controversial since introduced more than 150 years ago, simply because they contain 50% mercury, a known poison which is neurotoxic. A 2006 Zogby poll indicated that 76% of Americans were not aware that their silver fillings contained mercury, and would have chosen non-mercury fillings had they been advised of the mercury content known to be poisonous to every living cell.

Denmark, Sweden and Norway have already banned dental amalgam use, while other countries, including Canada, Germany, France and Italy, have restricted the use of dental amalgam for children, pregnant women, mothers who are breast feeding, people with kidney problems, and/or individuals with mercury sensitivity.

In 2006 FDA convened a joint meeting of its dental and neurology panels asking approval of the FDA "White Paper" which declared mercury fillings were not a danger. In an unlikely turn of events, the Joint Panel voted13 to 7 rejecting the FDA's contention. Despite the fact that FDA had no scientific support of their claim, three years later in July 2009 the FDA strongly endorsed the safety of mercury fillings, still with no credible scientific evidence that the general or vulnerable populations were not at risk.

The FDA's nearly unprecedented hearing next week on the claims of safety versus danger was prompted by a Petition for Reconsideration prepared by the IAOMT's attorneys Jim Love and Bob Reeves, which pointed out that FDA's past reporting of dental mercury disregarded the harm of mercury dosages on the vulnerable population of smaller size and lighter weight children, relying on improper assumptions and outdated reviews of scientific literature.

A new risk assessment by Dr. Mark Richardson and his colleagues at SNC-Lavalin Environmental sent to FDA by Love last month concludes that the mercury vapor from fillings is absorbed and distributed into every tissue and organ in the body including the brain, resulting in excessive exposure of this poison to 122 million Americans. The risk assessment proves that mercury from all sources such as fillings, vaccines, and fish is cumulative and compounded by other toxins particularly lead.

Matthew Young DDS, President of the IAOMT emphasized: "The cumulative dose and health effects of mercury from all sources will eventually force a ban on all optional use of this toxic metal. Mercury based fillings are the greatest contributor to mercury exposure in humans according to this recent risk assessment and the World Health Organization's Mercury Policy Report." Young calls for a ban now instead of years from now, stating "the elimination of mercury fillings will be the greatest health benefit to humankind."