Comprehensive and quantitative profiling of microflora of human apical periodontitis

点击翻译按钮获取中文摘要

The purpose of the present study was to profile microflora of root canals before and after root canal therapy, using real-time PCR, PCR-cloning, PCR-sequence analyses based on 16S rRNA genes. Informed consent was obtained from each subject and single-rooted teeth with periapical lesions were investigated. Upon access opening, each dentin sample was collected from the root canal. When the periapical lesion healed clinically through chemo-mechanical cleaning and intracanal medication, the root canal dentin sample was obtained again. The quantification of total bacterial DNA was performed by real-time PCR using universal primers based on 16S rRNA genes. PCR products were cloned and partially sequenced. The partial 16S rRNA gene sequences were then compared with those from the GenBank database using the Blast search program through the website of the NCBI (National Center for Biotechnology Information). The concentrations of bacterial DNA after root canal therapy were lower than those upon access opening. The PCR-cloning and PCR-sequence analyses revealed that Fusobacterium were initially predominant, and that Pseudomonas, Bradyrhizobium and Methylobacterium were predominant after root canal therapy. These results indicated that drastic shifts occurred in microflora of root canals by root canal therapy.