Dentistry 2012: What a difference a year makes

Clinical research advances

Beyond the many political issues that are changing the practice of dentistry, 2012 also saw a number of key advances on the clinical front.

One subject that continued to make headlines throughout 2012 was the oral-systemic health link. The American Heart Association (AHA) found itself in the hot seat with its contention that there is no conclusive scientific evidence that periodontal disease causes or increases the rates of cardiovascular diseases, or that regular brushing and flossing or treatment of periodontal disease can cut the incidence of atherosclerosis. While the association's statements were not incorrect, the dental community was up in arms at how the information was presented because it questioned the existence of any relationship -- not just causal -- between the two diseases.

Robert Genco, DDS, PhD, a distinguished professor of oral biology and microbiology at the University at Buffalo in New York who has spent years examining the link between periodontal disease and systemic diseases, didn't disagree with the AHA statement, but noted that "it is not completely unrealistic to expect an association between periodontal disease and heart disease because of inflammation."

In fact, a number of studies published this year support such an association:

• An oral health study conducted by United Concordia Dental and Highmark showed that pharmacy costs can average $1,477 lower per year for diabetes patients with periodontitis who receive at least seven treatments annually for the disease.
• Another study found that tracking adiposity changes in men may help predict their risk of periodontitis progression.
• Periodontal disease is four times more common among patients with rheumatoid arthritis than it is among their healthy peers, according to a study published in the Annals of the Rheumatic Diseases.
• Periodontitis increases the risk of developing oral leukoplakia and mucosal lesions that are predisposed to become oral cancer, according to a study in Oral Oncology.
• Patients with a history of periodontitis who develop head and neck squamous cell carcinoma are more likely to have human papillomavirus (HPV)-positive tumors, according to research from the University of New York at Buffalo
• While previous studies found a link between psoriasis and oral health, research published earlier this year in the Journal of Periodontology found no difference in the risk of periodontal disease between individuals with psoriasis and control subjects.

"It is uncanny how the inflammatory reaction occurs in other chronic inflammatory diseases and periodontitis," said Samuel Low, DDS, a past president of the AAP and a professor of periodontology at the University of Florida College of Dentistry, in a DrBicuspid special report on advances in periodontal research. "With diabetes, cardiovascular disease, Alzheimer's disease, and rheumatoid arthritis, for instance, if you review the way the inflammatory process works in those diseases, it is very close to the way it works with periodontal disease."

Researchers are also finding that not all oral bacteria are bad. The presence of microbes is in fact essential for maintaining the normal physiology of the oral cavity. While this symbiosis is usually stable and mutually beneficial, if some external force changes the balance, the result can be gingivitis, dental caries, or periodontal disease. In fact, today, a number of oral health products, from lozenges to mouthwashes, are designed to optimize the balance of bacteria in the mouth, retain their beneficial characteristics, and suppress their potentially harmful impact -- all part of a growing transition from "drill and fill" dentistry to preventive oral healthcare.

A related area of research that made much progress this year was salivary diagnostics. Clinical discoveries published in recent years have advanced the odds of salivary diagnostics becoming a chairside tool that could enhance the ability of dental practitioners to detect a spectrum of medical conditions.

Much of this work currently involves identifying disease-specific biomarkers that can be detected in saliva. For example, a team of researchers at the University of California, Los Angeles School of Dentistry has been awarded a $3.8 million grant to develop a salivary biomarker approach for identifying individuals at risk of developing post-traumatic stress disorder and depression following a traumatic event. And a Pennsylvania start-up is gearing up to launch a molecular saliva test that analyzes biomarkers to detect oral cancer and diabetes.

Similarly, a new "rinse and spit" test for early detection of oral cancer performed well in a clinical feasibility study, according to Vigilant Biosciences, the company commercializing the product. And a number of studies are finding that photodynamic therapy is effective in targeting oral dysplasia and potentially cancerous oral lesions.

Given the growing body of evidence linking certain strains of HPV with greater risk of oropharyngeal and head and neck cancers, these sorts of tools are becoming increasingly important.

"Oral sex with multiple partners is one of the significant risk factors for oral cancer and oropharyngeal cancer," wrote the authors of a study in the June 6 issue of Head and Neck Oncology. "Young people, who increasingly practice oral sex, especially with many partners, may be driving the increase in these cancers."

On a more positive note, however, a number of studies this year have found potential protective measures in everyday products, from green tea and cruciferous vegetables to statins (a cholesterol drug) and nisin (a common food preservative).

"It is important to realize that the common denominator to both prevention and treatment is to understand the natural history of oral cancer," stated Mine Tezal, DDS, PhD, a research professor in social and preventive medicine at the University of Buffalo School of Public Health and Health Professions whose current research is focused on the association between periodontitis and oral cancer. "If we understand that, it will spontaneously lead to effective strategies for both prevention and treatment."

Prevention or treatment of sources of inflammation in the oral cavity may be a simple yet effective way to reduce the acquisition and persistence of oral HPV infection, she added.

Editor's note: The next installment in the Future of Dentistry series, to be published in late January, will focus on advances in restorative dentistry, with particular emphasis on what's new in restorative materials and an update on the implant market.