Abstract
BACKGROUND AND OBJECTIVES: Dental caries is a progressive irreversible microbial disease. Different regions of the carious dentin contain different bacteria in various proportions. With the recent advent of new techniques in molecular biology, our understanding of the microbial agents associated with dental caries has grown tremendously. It is essential to identify and quantify the organisms from the diseased sites quickly and reliably. Fluorescent in situ hybridization is one such technique. Thus, the present study was aimed at estimating the prevalence of the bacteria Bifidobacterium dentium, Actinomyces naeslundii, and Propionibacterium in deep dental caries using FISH and comparing it with subgingival plaque samples. MATERIALS AND METHODS: A total of 60 subjects were included in the study. Two samples were obtained from one patient leading to a total of 120 samples. Carious samples were obtained for the test group, and for the control group, a subgingival plaque sample was collected. The collected specimens of the test group were transported in phosphate-buffered saline (PBS) and the subgingival plaque samples in reduced transport fluid. The samples were then processed for assessing the prevalence of the bacteria using fluorescence in situ hybridization (FISH). RESULTS: The results of the present study showed the presence of phylotypes B. dentium, A. naeslundii, and Propionibacterium species in deep dental caries. Although all the above-said phylotypes were present in deep dental caries, a statistically significant difference in the prevalence was only seen with respect to Propionibacterium species. CONCLUSION: FISH is a simple, quick, and versatile approach for bacterial identification and quantification. It also has a high sensitivity, allowing it to detect single bacterial cells. This method can be applied directly to clinical samples and utilized as a rapid diagnostic tool for detecting the presence of newer phylotypes in deep dental caries.