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

使用标准培养技术已经从根管中分离出相对广泛的细菌。然而，口腔中只有50%的细菌是可培养的。因此，牙髓感染的细菌多样性被低估了。本研究使用基于PCR的16S rRNA或细菌物种特异性基因测定来评估感染根管中存在的细菌的多样性。针对细菌16S rRNA和细菌种特异性基因的PCR引物用于鉴定难治性根尖周炎根管内的假定细菌病原体。此外，这些微生物与症状和根管治疗史的协会进行了调查。本研究收集了难治性根尖周炎患者根管中的微生物标本，在根尖周放射线覆盖面积较大的根管中检出最多的是具核梭杆菌（62.5%），在根尖周放射线覆盖面积较大的根管中检出最多的是齿垢密螺旋体（62.5%），在根尖周放射线覆盖面积较大的根管中检出最多的是具核梭杆菌（62.5%），在根尖周放射线覆盖面积较大的根管中检出最多的是齿垢密螺旋体（62.5%） ...更多信息 培养后还检出了坦那氏菌和牙龈卟啉单胞菌。从根管恶臭或渗出液的样品与牙龈卟啉单胞菌的存在。粪肠球菌，这被认为是难治性根尖周炎相关的微生物，也检测到样品。除细菌外，还检测到真菌之一的白色念珠菌（Candida albicans）为菌丝型和酵母型。结果提示，在根管治疗过程中，根管内仍有多种细菌存活。根管化学机械清洗和成形后，在根管手术中，根管显微镜观察发现根管尤其是根尖区的折裂，这些观察结果表明，难治性慢性根尖周炎病变是由于细菌侵入并生长于根尖区，而根尖区由于某种原因而被破坏，并提示具核梭菌，T.lasthensis和P.gingivalis与难治性根尖周炎有关。少

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