New Method May Help Identify Bacteria That Causes Severe Dental Decay In Early Childhood

Severe early-childhood caries (S-ECC) is an extremely destructive form of bacterial tooth decay generally involving multiple teeth. Although previous studies have indicated Streptococcus mutans as a potential agent, researchers have yet to determine if S-ECC is caused by a single strain of bacteria or a group of bacterial species. Prior testing based on cultivation methods has proven difficult because nearly half of the bacteria in saliva and dental plaque are not cultivable.

In the study researchers collected plaque samples from twenty children, some with S-ECC and some caries-free (CF), and evaluated the difference in bacterial diversity using denaturing gradient gel electrophoresis (DGGE), a cultivation-free method which isolates total microbial genome DNA. Results showed the S-ECC group exhibited 94.5 bacterial populations while the CF group exhibited 113.4, suggesting that caries-associated bacteria become less diverse as specific groups begin to dominate the plaque biofilm.

"These results suggest that the microbial diversity and complexity of the microbial biota in dental plaque are significantly less in S-ECC children than in CF children," say the researchers. "Our study also demonstrated that PCR-based 16S rRNA gene DGGE is a sufficiently valuable tool for differentiating the microbial composition of the oral plaque in S-ECC children from that of CF children and may be further developed as a pattern recognition tool with which to identify specific group of bacteria predominantly colonized in children of various caries status."

(Y. Li, Y. Ge, D. Saxena, P.W. Caufield. 2006. Genetic profiling of the oral microbiota associated with severe early-childhood carries. Journal of Clinical Microbiology, 45. 1: 81-87.)