Microbial profiling of dental caries and periodontitis patients using denaturing gradient gel electrophoresis

Abstract

Oral cavity contains a diverse group of microorganisms which changes from normal to diseased condition like dental caries and periodontitis. It is hard to depict the complete picture of microbial environment as some species are uncultivable. In this study we detected the microbial diversity of normal, dental caries and periodontal group by using culture independent PCR based denaturing gradient gel electrophoresis (DGGE). DNA was extracted from plaque samples from patients, and PCR was conducted for the 16s rRNA gene with universal primer, followed by DGGE, excision of bands, cloning and sequencing. It was determined that the number of bands detected in normal group (17.06 ± 4.34) was more than dental caries (12.73 ± 3.2) and periodontitis group (10.36 ± 3.5). On clustering they formed mixed clusters. Sequencing results showed that dental caries group contained large proportion of Gram positive bacteria, while periodontitis group contained mostly Gram negative bacteria. Diversity in dental caries and periodontitis groups were less as compared to normal group which suggested that the presence of only cariogenic bacteria and those who tolerate low pH contributes in dental caries and some typical bacteria responsible for causing periodontitis. DGGE is the effective tool to dissect any microbial niche in the body.