Analysis of bacterial invasive lesion of refractory periapical periodontitis cases by genetic engineering technique

点击翻译按钮获取中文摘要

A relatively wide range of bacteria have been isolated from root canals using standard culture techniques. However, only 50% of the bacteria in the oral cavity are cultivable. Hence, bacterial diversity in endodontic infections is underestimated. This study used a PCR-based 16S rRNA or bacterial species-specific gene assay to assess the diversity of bacteria present in infected root canals. PCR primers that target the bacterial 16S rRNA and bacterial species-specific genes were used to identify putative bacterial pathogens in root canals with refractory periapical periodontitis. In addition, the associations of these microorganisms with symptoms and a history of endodontic treatment were investigated. Microbial samples from root canals with refractory periapical periodontitis were included in this study.Fusobacterial nucleatum (62.5%) were most frequently detected in the samples from root canals with relatively large peripaical radiolucent area, and Treponema denticola, which is diffic … More ult to culture, Tannerella forsythesis and Porphyromonas gingivalis were also detected. Samples from root canal with foul odor or exudates fluid were associated with the presence of P.gingivalis. Enterococcus faecalis, which is suggested as refractory periapical priodontitis-related microorganism,was also detected in samples. In addition to the bacteria, Candida albicans, one of the fungi, was detected as both hypha and yeast types. These results suggested that various bacterial species still survived in root canals during the root canal treatment. After chemomechanically cleaning and shaping of root canal, the fractures of the root, especially apex area, were found by the endodontic microscopy observation at the endodontic surgery.These observations suggest that refractory chronic periapical periodontitis lesion is formed by bacterial invasion and growth in the area of root apex destroyed by some reasons, and indicated that F.nucleatum, T.forsythensis and P.gingivalis are associated with refractory periapical periodontitis. Less