Department of Endodontics and Molecular Microbiology Laboratory, Estácio de Sá University, Rio de Janeiro, Rio de Janeiro, Brazil.
J Endod. 2011 Nov;37(11):1499-503. doi: 10.1016/j.joen.2011.08.012. Epub 2011 Sep 16.
Bacterial biofilm communities established in the apical part of infected root canals are conceivably of utmost importance in the pathogenesis of apical periodontitis. This study investigated the diversity of the apical endodontic microbiota by using cryopulverized root segments and massive parallel pyrosequencing analysis.
Ten extracted teeth with attached apical periodontitis lesions were sectioned to obtain 2 root fragments (apical and middle/coronal segments). Apical root fragments were cryogenically ground, and DNA was extracted from samples and subjected to multiplex tag-encoded FLX-titanium amplicon pyrosequencing.
Pyrosequencing analysis yielded partial 16S rRNA gene sequences that were taxonomically classified into 187 bacterial species-level phylotypes (at 3% divergence), 84 genera, and 10 phyla. The most represented, abundant, and prevalent phyla were Proteobacteria, Firmicutes, Bacteroidetes, Fusobacteria, and Actinobacteria. The majority of species-level phylotypes occurred at low levels. The mean number of species-level phylotypes per sample was 37 (range, 13-80). A great interindividual variation in the composition of the apical microbiota was disclosed.
This study extensively describes the diversity of the bacterial communities present selectively in the apical part of root canals of teeth with apical periodontitis and revealed a previously unanticipated high bacterial diversity.
感染根管根尖部分建立的细菌生物膜群落，在根尖周病的发病机制中可能具有至关重要的作用。本研究通过使用冷冻粉碎的根管段和大规模平行焦磷酸测序分析来研究根尖牙髓微生物群的多样性。
10 颗附有根尖周病病变的拔出牙齿被切成 2 个根段（根尖和中/冠段）。将根尖根段冷冻研磨，从样本中提取 DNA，并进行多重标记编码 FLX-钛扩增子焦磷酸测序。
焦磷酸测序分析产生了部分 16S rRNA 基因序列，这些序列在分类学上被分为 187 个细菌种水平的分类群（差异为 3%）、84 个属和 10 个门。最具代表性、丰富和常见的门是变形菌门、厚壁菌门、拟杆菌门、梭杆菌门和放线菌门。大多数种水平的分类群水平较低。每个样本的种水平分类群平均数为 37 个（范围为 13-80）。个体间根尖微生物群组成的差异很大。
本研究广泛描述了存在于根尖周病牙齿根管根尖部分的细菌群落的多样性，并揭示了以前未预料到的高细菌多样性。
