【作者】 张琛； 侯本祥；

【Author】 Zhang Chen Hou Ben-xiang(Department of Endodontics,School of Stomatology,Capital Medical University,Beijing,100050)

【机构】 首都医科大学口腔医学院牙体牙髓科；

【摘要】 目的:虽然了解持续性根尖周炎可能与持续存在的根外感染有关,但在持续性根尖周炎根尖病损内和根尖生物膜内细菌的组成特点和作用还不清楚。本实验的目的是鉴定持续性根尖周炎根尖生物膜内和根尖周病损组织内的细菌图谱,详细了解持续性根尖周炎感染根管外的菌群构成特点,根尖周两种组织内细菌的相互关系。方法:选择持续性根尖周炎需行根尖手术的患牙18例,对其根尖和根尖周组织分别取样,提取全细菌基因组DNA,采用配对x 2检验的McNemar Test比较持续性根尖周炎根尖周组织和根尖外表面生物膜细菌检出率,选择2种组织中均有细菌检出的1 0例持续性根尖周炎病例,对其10对根外组织构建1 6S rDNA克隆文库,采用1 6SrDNA克隆测序法分析细菌的多样性及进行种群分类,检测优势菌,并应用配对秩和检验比较2种根外组织中各种细菌的检出量。选择持续性根尖周炎需行根尖手术的患牙4例,切取根尖后样本处理,激光共聚焦显微镜观察根尖表面。结果:根管外样本中检出78种菌,在根尖生物膜内检出的细菌种类和克隆数均高于根尖周组织,根尖周组织内未培养菌相对根尖生物膜多,Enterococcus faecalis,Streptococcus anginosus和Mogibacterium timidum是两种样本中的优势菌。Streptococcus intermedius,Campylobacter gracilis,Pseudomonas aeruginosa,Propionibacterium propionicus,Abiotrophia adiacens和Lactobacillus gasseri在根尖生物膜内检出显著高于根尖周组织(P<0.05),而Parvimonas micros和Atopobium rimae在根尖周组织中检出显著高于根尖生物膜(P<0.05)。激光共聚焦显微镜观察到4例持续性根尖周炎患牙表面均有根尖生物膜的存在。结论:持续性根尖周炎存在根外感染,为包括许多未培养菌的多细菌感染;根外感染的部位包括根尖生物膜和根尖周组织,根外感染检出的大部分细菌从根尖生物膜和根尖周组织中均能检出,说明二者的细菌感染来源是相同的,但在构成种类和检出量也存在明显的不同。明确侵入到根管外的细菌以植于根尖周组织中或以根尖生物膜形式引起慢性的持续性的感染。更多还原

【Abstract】 OBJECTIVE:Microorganisms are able to survive and induce persistent infection in periapical tissues.The microbial etiology of periradicular lesions is recognized;however, the individual contributions of bacteria within the extraradicular biofilm and periradicular lesion is not well elucidated.The purpose of this study was to characterize the bacterial community present in the extraradicular biofilm and periradicular lesion.METHODS: Eighteen adult patients who presented for apicoectomy of persistent periradicular lesions after endodontic therapy were selected for the study and samples of extraradicular biofilm and periradicular lesion collected.Ten pairs of extraradicular biofilm and periradicular lesion were analyzed using ribosomal 16S cloning and sequencing for bacterial identification. RESULTS:Bacteria were detected more consistently and at higher levels in extraradicular biofilms.Periradicular lesions exhibited a diverse microbial profile with many uncultivated phylotypes.Enterococcus faecalis,Streptococcus anginosus and Mogibacterium timidum predominated in both samples.Streptococcus intermedius,Campylobacter gracilis,Pseudomonas aeruginosa,Propionibacterium propionicus,Abiotrophia adiacens and Lactobacillus gasseri were associated with extraradicular biofilms,whereas only Parvimonas micros and Atopobium rimae were associated with periradicular lesions. CONCLUSION:Persistent periradicular lesions are polymicrobial infections with many as-yet -uncultivated bacterial species.The bacterial load and microbial profile of extraradicular biofilms is significantly different from the soft-tissue lesion,indicating the presence of diverse bacterial populations in these tissues.更多还原