Scientists seeking to predict a person's risk for developing dental caries by identifying the presence of harmful oral bacteria have to date identified only about 800 of the thousands of microbes residing in the human oral cavity. But now a multimillion dollar grant from the National Institutes of Health (NIH) to the J. Craig Venter Institute, in collaboration with the NYU College of Dentistry, is underwriting a four-year study that utilizes a new genetic sequencing technique to speed the process of identifying those remaining bacteria that play the most important role in tooth decay. The principal investigator on the grant is Dr. Scott Peterson, Director of Functional Genomics Research Technology for the Venter Institute. Dr. Walter Bretz, Associate Professor of Cariology & Comprehensive Care, is the principal investigator on a subcontract of the grant awarded to the NYU College of Dentistry.
"The new technique, known as enrichment gene sequencing, will enable us to uncover the existence of many more species than those that have been identified so far with traditional sequencing," said Dr. Bretz.
"Traditional sequencing quickly reaches a saturation point at which it can no longer uncover new species," added Dr. Bretz. "By enriching the genomic DNA, we can make way for additional species to surface."
Enrichment gene sequencing will also enable the investigators to ascertain the role of each microbial species, so that it can be classified as either a "bad" one that contributes to tooth decay, or a "good" one that helps to prevent the disease.
Samples for the study will be drawn from 100 pairs of twins, ages 6 to 18, selected from a database of 1,500 twin pairs developed by Dr. Bretz for the Twins Institute for Genetics Research in Montes Claros, Brazil. Half of the paired twins in the study have caries, the other half are free of the disease. Because they live together and have similar dietary habits and health practices, twins are considered excellent subjects for research that compares caries development in people of the same age from similar environments.
According to Dr. Bretz, "The oral microbial profile we develop will enable us to predict which of the twins are likely to develop caries, and which will remain healthy."
Dr. Nicholas Schork, Director of Genomic Medicine at the Scripps Hospitals, in San Diego, California, is a coinvestigator on the grant. Additional coinvestigators include Dr. Alexandre Moreira, Director, and Dr. Andrea Corby, Clinical Director, of the Twins Institute for Genetics Research.