Thursday, January 29, 2009

Periodontal treatment doesn't cut preterm births

New data show periodontal treatment doesn't reduce preterm birth risk

The study, involving researchers from Duke University Medical Center and the University of North Carolina at Chapel Hill, is one of the largest randomized trials to date to look at the link between the two conditions.

Previous research had suggested that gum disease was associated with very preterm deliveries (defined as less than 32 weeks gestation). That led insurance policies and healthcare providers to recommend scaling and root planing, sometimes referred to as "deep cleaning," in pregnant women. It was thought that such care had the potential to reduce preterm delivery risk.

These new findings, based on a randomized trial of 1,800 pregnant women with periodontal disease, indicate that routine gum treatments do not reduce the risk of early delivery.

"I'm always asked whether we should mandate dental treatment for all pregnant women," said Amy Murtha, MD, director of obstetrics research at Duke University Medical Center in Durham, NC, who presented the findings at the annual meeting of the Society for Maternal-Fetal Medicine in San Diego. "The biggest implication of this study is that this level of standard periodontal care will not affect the birth outcome."

That's not to say pregnant women should not get dental exams and treatment as needed; they should, Murtha added. "Our study emphasizes that treating periodontal disease during pregnancy is safe, but that standard periodontal care is not enough."

Progression, or worsening of periodontal disease occurs in about 25 percent of pregnancies, said Steven Offenbacher, DDS, PhD, the study's lead investigator and director of the UNC-Chapel Hill School of Dentistry-based Center for Oral and Systemic Diseases. The bacterial infection attacks the teeth-supporting tissues below the gum line. Left untreated, it can lead to tooth loss as well as a host of other problems.

This study, conducted at Duke, the University of Alabama at Birmingham and the University of Texas at San Antonio, was overseen by the UNC-Chapel Hill School of Dentistry. Pregnant women with periodontal disease were randomly assigned to two groups: one received periodontal treatment before 23 weeks gestation; the other did not. Overall, no significant differences were reported regarding obstetric or neonatal outcomes when the two groups were compared.

Despite the findings, Murtha said much remains unknown about the relationship between the two conditions. "Periodontal disease and poor pregnancy outcomes travel together, but we don't know why."

Nor do researchers understand how or why pregnancy appears to jumpstart the onset and progression of the disease. Murtha said it may be that preterm birth and periodontal disease share a common underlying trait, such as an exaggerated inflammatory response, but more studies are needed to fully explain the connection.

Additional research is also needed to determine whether more intensive periodontal care during pregnancy might make a difference. "Although we did not reduce the risk of preterm births, the level of periodontal care provided in this study was not as effective as compared to earlier studies," Offenbacher said. It may be that a more aggressive approach to periodontal disease management could have a different outcome, he added.

UV Light Bad Approach to Bleaching

UV light-enhanced tooth bleaching is not only a con, but is dangerous to your eyes and skin, says a Royal Society of Chemistry journal.

The light treatment gives absolutely no benefit over bleaching without UV, and damages skin and eyes up to four times as much as sunbathing, reports a study in Photochemical & Photobiological Sciences.

Those looking to match Tom Cruise's glittering pearly-whites would be better off ignoring claims of better bleaching with UV light treatment.

The treatment is at least as damaging to skin and eyes as sunbathing in Hyde Park for a midsummer's afternoon – one lamp actually gave four times that level of radiation exposure.

And as with sunbathing, fair-skinned or light-sensitive people are at even greater risk, said lead author Ellen Bruzell of the Nordic Institute of Dental Materials.

Bruzell also found that bleaching damaged teeth. She saw more exposed grooves on the enamel surface of bleached teeth than on unbleached teeth. These grooves make the teeth more vulnerable to mechanical stress.

Tooth bleaching is one of the most popular cosmetic dental treatments available. It uses a bleaching agent – usually hydrogen peroxide – to remove stains such as those from red wine, tea and coffee, and smoking.

UV light is claimed to further activate the oxidation process, improving bleaching efficiency. The authors of this Photochemical & Photobiological Sciences article say there is very little substantive evidence to support this claim, and their new study finds no benefit to using UV light.

Cures for TMJD?

For millions of people with mysterious pain of the jaw region, there may be help on the way.

Researchers at the University of Maryland Dental School hope their new seven-year, $17 million study of 3,400 study subjects will finally identify the cause and effect, and point to possible cures for temporomandibular joint and muscle disorders (TMJD).

For most people, the discomfort from the commonly called "TMJ" group of disorders will eventually go away with little or no treatment says the National Institute of Dental and Craniofacial Research (NIDCR) in Bethesda. However, many TMJD patients develop significant, long-term problems that cause chronic pain and dysfunction in the jaw joint and muscles that control jaw movement.

As much as 2 percent of the U.S. population suffers from TMJD, with more women than men appearing to have the condition, but doctors and scientists know little about the causes, and so there are few effective treatments.

Joel Greenspan, PhD, a professor and chair of the Department of Neural and Pain Sciences at the Dental School, says that most people know someone with the disorder or have heard their doctor suggest that a pain may be TMJD. "But, there is often little or nothing physically wrong that can be identified. And, frequently the pain is not specifically focused or limited to the jaw," he says.

Common characteristics of TMJD include pain, limitations in mobility and function, and jaw joint noises─clicks, pops, catches, or locks when the mouth is opened. TMJD is the second leading cause of pain for people who report facial or head pain.

Greenspan is one of the principle investigators in the $17 million “Orofacial Pain: Prospective Evaluation and Risk Assessment” (OPPERA) study, funded by the, NIDCR, which is part of the National Institutes of Health. OPPERA is being conducted at four sites, the University of Maryland Dental School, and the universities of Buffalo, North Carolina, and Florida dental schools. It is headed by William Maixner, DDS, PhD, Center for Neurosensory Disorders, School of Dentistry, University of North Carolina.

In some cases, the disorder can be brought on by trauma. Greenspan said some dental procedures can bring it on, but that is uncommon. It can also be brought on by misalignment of teeth, which is most often hereditary. Overuse of the jaw is another possible cause. Excessive gum chewing, nail biting, and gnawing on items like plastic straws can overtax the muscles of this joint.

"The main purpose of our OPPERA study is to identify the precursors in a prospective way, thus allowing us to more formally determine cause and effect, rather than just associations”, said Greenspan. He said there have been very few studies that address the cause of the disorder in a prospective manner, and none of the size and comprehension of OPPERA. Almost all of the clinical literature studies on TMJD are either observations on TMJD patients, or case-control studies.

Historically, doctors routinely recommended surgery to try to correct TMJD, but surgery is no longer a leading recommendation. Dental treatments include filing teeth down to make them fit better in the bite, or using dental appliances to even out the bite, like a match box under a table leg. "But, sometimes grinding makes things worse and may not be the answer. Noninvasive techniques are better recommended, such as appliances or reduced stress through exercise," said Greenspan.

TMJD occurs at least two times more frequently in women than in men, and often with more severe symptoms in women, perhaps because women are more pain sensitive, he said. "Several studies conducted here and elsewhere have shown that under controlled test conditions, women report standard test stimuli as more painful than men. Recent testing we have completed indicates that the brain’s processing of pain is amplified more in women than men, and even more so in women suffering with TMJD.”

In an NIDCR survey of 42,370 adults, (ages 18 to 75 and older) over a six-month period prior to Dec. 20, 2008, 3.5 percent of males and 6.9 percent of females reported pain in the jaw joint or in front of the ear more than once. The average for participants ages 75 and older of both sexes combined was 3.9 percent, but the average for those in the 18 to 34 year old group was 6.5 percent.

One mystery of the disorder is that the pain is not necessarily directly focused on the jaw, while another is that the pain is not related to the extent of tissue injury. This doesn’t surprise Greenspan because, he says, pain is the result of multiple system changes. "This is a complex area," he says, involving the three factors underlying pain: genetics, psychology, and physiology.

Friday, January 9, 2009

Mechanism for dental pain discovered

Researchers at Oregon Health & Science University's School of Dentistry ( have discovered a novel function of the peptide known as Nerve Growth Factor (NGF) in the development of the trigeminal nerve. The trigeminal nerve provides the signaling pathway for periodontal pain, dental surgical pain, and pain associated with temporomandibular disorder, trigeminal neuralgia, migraine, and other neuropathic and inflammatory conditions.

The study is posted online ( in the journal Neuropeptides and will appear in print issues of that journal in early 2009.

Working with researchers in the dental school departments of Endodontology and Integrative Biosciences, second-year endodontology resident and lead author of the study, Leila Tarsa, D.D.S., M.S., found a new mechanism involved in establishing junctions – known as synapses – between trigeminal nerve cells. Nerve cells communicate with one another through chemicals called transmitters that are released at synapses. The transmitter release from nerve cells endings is possible only if aided by several molecules that are critical for proper function of the synapse. Tarsa's research shows that NGF promotes transport of one of the molecules (called synaptophysin) from the nerve cell body to its ending.

"The data indicate that NGF participates in formation of neuronal connections in the trigeminal system," said Agnieszka Balkowiec, M.D., Ph.D., OHSU School of Dentistry assistant professor of integrative biosciences and OHSU School of Medicine adjunct assistant professor of physiology and pharmacology, who is the senior author of the study and whose lab hosted the research. "This study has broad implications for trigeminal nerve regeneration."

Monday, January 5, 2009

USC dentist: Fosomax-type drugs = jaw necrosis

Study is among first to link short term drug use for osteoporosis to bone death

Researchers at the University Of Southern California, School Of Dentistry release results of clinical data that links oral bisphosphonates to increased jaw necrosis. The study is among the first to acknowledge that even short-term use of common oral osteoporosis drugs may leave the jaw vulnerable to devastating necrosis, according to the report appearing in the January 1 Journal of the American Dental Association (JADA).

Osteoporosis currently affects 10 million Americans. Fosomax is the most widely prescribed oral bisphosphonate, ranking as the 21st most prescribed drug on the market since 2006, according to a 2007 report released by IMS Health.

"Oral Bisphosphonate Use and the Prevalence of Osteonecrosis of the Jaw: An Institutional Inquiry" is the first large institutional study in the U.S. to investigate the relationship between oral bisphosphonate use and jaw bone death, said principal investigator Parish Sedghizadeh, assistant professor of clinical dentistry with the USC School of Dentistry.

After controlling for referral bias, nine of 208 healthy School of Dentistry patients who take or have taken Fosamax for any length of time were diagnosed with osteonecrosis of the jaw (ONJ). The study's results are in contrast to drug makers' prior assertions that bisphosphonate-related ONJ risk is only noticeable with intravenous use of the drugs, not oral usage, Sedghizadeh said. "We've been told that the risk with oral bisphosphonates is negligible, but four percent is not negligible," he said.

Most doctors who have prescribed bisphosphonates have not told patients about any oral health risks associated with the use of the drugs, despite even short-term usage posing a risk due to the drug's tenacious 10-year half life in bone tissue. Lydia Macwilliams of Los Angeles said no one told her about the risk posed by her three years of Fosamax usage until she became a patient of Sedghizadeh at the School of Dentistry. "I was surprised," she said. "My doctor who prescribed the Fosamax didn't tell me about any possible problems with my teeth."

Macwilliams was especially at risk for complications because she was to have three teeth extracted. The infection is a biofilm bacterial process, meaning that the bacteria infecting the mouth and jaw tissues reside within a slimy matrix that protects the bacteria from many conventional antibiotic treatments, and bisphosphonate use may make the infection more aggressive in adhering to the jaw, Sedghizadeh said. The danger is especially pronounced with procedures that directly expose the jaw bone, such as tooth extractions and other oral surgery. After her extractions, two of the three extraction sites had difficulty healing due to infection, Macwilliams said. Luckily, with treatment as well as the rigorous oral hygiene regimen USC dentists developed especially for patients with a history of bisphosphonate usage, the remaining sites slowly but fully healed. "It took about a year to heal," she said, "but it's doing just fine now."

Sedghizadeh hopes to have other researchers confirm his findings and thus encourage more doctors and dentists to talk with patients about the oral health risks associated with the widely used drugs. The results confirm the suspicions of many in the oral health field, he said. "Here at the School of Dentistry we're getting two or three new patients a week that have bisphosphonate-related ONJ," he said, "and I know we're not the only ones seeing it."