目的研究慢性根尖周炎感染根管中微小小单胞菌(Parvimonas micra,Pm)的检出情况以及与慢性根尖周炎临床症状、体征的关系。方法采集104名慢性根尖周炎患者的120颗患牙根管内标本,其中包括初次治疗组(A组)和再次治疗组(B组)各60颗患牙。利用16S r DNA聚合酶链反应技术检测标本中的微小小单胞菌16S r DNA的表达;用比值比(OR值)的方法,分析Pm检出率与慢性根尖周炎临床症状及体征的关系。结果慢性根尖周炎初次治疗组检出Pm 24例,再次治疗组检出Pm 3例。2组结果通过比值比分析发现,随检出Pm几率增加,慢性根尖周炎根管内出现恶臭(A组OR=3.35,B组OR=14.29)或根尖出现大于5mm的根尖病变(A组OR=2.75,B组OR=6.70)的几率随之增加,95%可信区间下限>1,结果有显著性差异(P<0.05)。结论无论在初次治疗或再次治疗的慢性根尖周炎感染根管中均有Pm检出。Pm可能在该疾病的发生发展过程中发挥一定作用。
Background Persistent/secondary infections of human root canals play an important role in the failure of endodontic treatment. This study used 16S rRNA sequencing to assess microbial diversity in root-filled teeth associated with failed endodontic treatment. Methods DNA was extracted from 15 teeth with persistent intraradicular infections, and the 16S rRNA of all present bacteria were amplified by PCR, followed by cloning and sequencing of the 16S rRNA amplicons. Results All sample extracts were positive for PCR amplification using the universal 16S rRNA gene primers. Negative control reactions yielded no amplicons. Sixty-five phylotypes belonging to seven phyla were identified from 760 clones; a mean of 9.4 phylotypes were detected in each sample （range 3-15）. Twenty-eight phylotypes were detected in more than one sample, revealing a high inter-sample variability. Parvimonas micra （60%, 9/15）, Solobacterium moore （47%, 7/15）, Dialister invisus （33%, 5/15）, Enterococcus faecalis （33%, 5/15）, Filifactor alocis （27%, 4/15）, and Fusobacterium nucleatum （27%, 4/15） were the prevalent species. Nineteen as-yet-uncultivated phylotypes were identified, comprising a substantial proportion of the bacteria in many cases. Conclusions Persistent intraradicular infections were present in all root-filled teeth associated with failed endodontic treatment. The current observations reveal new candidate endodontic pathogens, including as-yet-uncultivated bacteria and phylotypes that may participate in the mixed infections associated with post-treatment apical periodontitis.
