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If you’re diligent about your oral health yet still prone to cavities, it might not be your fault. It could be linked to your genes.

Researchers from the University of Pittsburgh School of Dental Medicine have found that certain genetic variations may be the cause of tooth decay and aggressive periodontitis and have published two papers on the topic.

According to Dr. Alexandre Vieira, an assistant professor of oral biology at Pitt and senior author of both papers, the rate of dental caries can be influenced by individual variations, or polymorphisms, in a gene called beta defensin 1 (DEFB1), which plays a key role in the first-line immune response against invading germs.

In the first paper, published in the Journal of Dental Research, “we were able to use data gathered from our dental registry and the DNA Repository — the only one of its kind in the world — to see if certain polymorphisms were associated with the development of caries,” said Dr. Vieira.

“This could help us find new ways to treat people who are particularly susceptible to tooth decay, a problem that afflicts millions of Americans.”

By analyzing nearly 300 anonymous dental records and accompanying saliva samples from Pitt’s registry, the researchers assigned each case a DMFT score (a score based on sum of permanent teeth that are decayed, missing or filled) and a DMFS score (based on the sum of teeth that are decayed, missing teeth and which have filled surfaces.) Generally, individuals with fewer caries have lower DMFT and DMFS scores. All of the saliva samples contained one of three variants, dubbed G-20A, G-52A and C-44G, of the DEFB1 gene.

The researchers reported that individuals who carried a G-20A copy had DMFT and DMFS scores that were five-times higher than for people who had other variants. The G-52A polymorphism was associated with lower DMFT scores.

In a second paper, published online at PLoS one, an online journal dedicated to peer-reviewed scientific and medical research, Vieira and Pitt researchers collaborated with researchers from Brazil to study saliva samples of 389 people in 55 families. They used these samples to look for genetic links to aggressive periodontitis, which is rapid and severe destruction of the gums and bone more commonly found in Africans and those of African descent, according to the paper.

The researchers reported finding hints of an association between the disease and the FAM5C gene and other experiments showed elevated levels of FAM5C expression, or activation, in areas of diseased periodontal tissue compared to healthy tissue.

“The FAM5C gene recently was implicated in cardiovascular disease, in which inflammation plays a role, just as in periodontitis,” Vieira says. “More research is needed to see if variation in the gene is associated with different activity profiles.”