University Times

Cavities affect 80 percent of the world’s population and are five times more common than asthma in the United States. While dental caries are the most common non-contagious human disease, little is known about how long it takes for cavities to form.

Dental school faculty member Alexandre Vieira discussed his research into the genetic differences that affect susceptibility to caries Dec. 2 as part of the Schools of the Health Sciences Senior Vice Chancellor’s Research Seminar Series.

Vieira, who holds a secondary appointment in the Graduate School of Public Health’s Department of Human Genetics, established and directs the dental school’s Dental Registry and DNA Repository, the world’s only genotype-dental phenotype registry.

While cavities often are considered inevitable, failing to treat tooth decay can lead to dire consequences.

Vieira cited journal literature document

Alexandre Vieira

ing a case in Greece in which a patient’s tooth extraction led to an abscess that resulted in loss of vision. “All from a single tooth that wasn’t treated,” Vieira said.

News reports in the United States included the 2007 story of a Washington, D.C., 12-year-old who died from untreated dental decay and the more recent story of a 24-year-old Cincinnati man who died from an untreated tooth infection earlier this year.

Cavities are caused by an imbalance between the loss of a tooth’s surface minerals (which occurs when plaque accumulates) and the remineralization that occurs quickly in healthy people. “Disease comes from an unbalance of mineral losses and mineral gains,” Vieira said. The challenge is in understanding how that process progresses before visible lesions are detected on the teeth.

Although cavities are highly preventable, “we don’t do a good job of accomplishing that,” Vieira said. “There is evidence that we have to be stronger and more bold in assessing the disease.”

Vieira said, “I don’t think anyone knows how long it takes for the process to develop. That’s the challenge. We have a measure for the lesions, but not a good measure for the disease.”

Personal habits, fluoride and genetic factors all play a role in the development of cavities. Age is a factor as well, said Vieira, who has devoted some of his research to uncovering which genes have an influence.

Given that “most of the attack in our lives will happen in the first decade of life,” the influence of genetics should be apparent by age 12, he noted.

Some of Vieira’s research followed the identification of some cavity-free children in the Philippines. “And they’d never seen a dentist or brushed in any particular way,” he said. Other cohorts are being studied in Pittsburgh, South and Central America and Turkey.

Vieira said genes that influence immune response and tooth enamel formation factor into who is more susceptible to caries. And new research not yet published is finding links to the genes that affect saliva function.

Vieira said research is continuing into factors including how proteins in saliva behave, how tooth enamel responds and the effect of fluoride. The next stage, he said, will look at the role of bacteria in the progression of tooth decay.

He said he hopes to develop a tool that can be used in the clinic to better identify who may be most at risk.

—Kimberly K. Barlow