OBJECTIVETo investigate the microbial composition and differences in dental plaque of caries and caries-free adults.

METHODSCaries-active (n = 16) was defined as an individual who had at least three untreated decayed tooth and decayed-missing-filled-tooth (DMFT) score greater than 6. Caries-free (n = 16) was defined as an individual who had a DMFT score equal to zero. The patients were 18-35 years old. Samples from supra-gingival plaque were obtained and PCR-denaturing gel electrophoresis cloning and sequencing of caries pathogens were used to catch the core microbial of dental caries.

RESULTSSix phylum, 28 genus and 88 species were detected. In caries group, Prevotella, Capnocytophaga, Actinomyces, Veillonella and Corynebacterium were predominant, accounting for 56.2% (334/594) of the total cloning number of caries group. Caries-free group contained more predonminant genus than caries group. Prevotella, Veillonella, Capnocytophaga, Corynebacterium, Streptococcus, Actinomyces, Aggregatibacter and Neisseria were predominant, accounting for 65.2% (354/543) of the total cloning number of caries-free group. Caries group had less diversity than the caries-free group. The difference was statistically significant (P < 0.05).

CONCLUSIONSCaries might be caused by potentially pathogenic microbial communities rather than a single pathogen. In the progress of dental caries, the microbial diversity decreased.