Objective To investigate the bacterial components of periapical lesions in deciduous teeth.Methods Tissue samples were collected from 13 periapical lesions in deciduous teeth with chronic periapical periodontitis.DNA was extracted and analyzed using 16SrDNA cloning and sequencing for identification of bacteria.Results All DNA samples were positive.One hundred and sixty-seven phylotypes including forty-eight as-yet-uncultivated phylotypes from 953 clones were identified belonging to eight phyla.Firmicutes was the dominant phyla that accounted for 47.9％ of the phylotypes,while Proteobacteria and Bacteroidetes were accounted for 26.9％ and 13.2％,respectively.Seventy-six phylotypes were detected in more than two samples,Fusobacterium nucleatum (76.92％) Dialister invisus (76.92％),Campylobacter gracilis (61.54％),Streptococcus sanguis (53.85％),and Streptococcus mitis (53.85％) were the most prevalent species.Conclusion Chronic periapical lesions in deciduous teeth contained polymicrobial infections with many as-yetuncultivated bacterial species,and the dominant bacteria of periapical lesions were associated with that of infected root canals.%目的 检测乳牙慢性根尖周病损组织中菌群构成,以期进一步阐明乳牙慢性根尖周感染细菌病因学特点.方法 收集13例乳牙慢性根尖周炎患儿的根尖周病损组织,采用16S rDNA克隆测序法检测样本中菌群构成.结果 PCR扩增16S rDNA通用引物获得的所有DNA样本均为阳性.13例乳牙慢性根尖周病损组织样本共获得953个克隆,鉴定出167个菌种或基因型,从属于8个菌门,其中48种细菌为未培养菌.检出菌种中厚壁菌门最多(47.9％),其次为变形菌门(26.9％)和拟杆菌门(13.2％).在2个以上样本中检出的细菌共有76种,检出率最高的为具核梭杆菌和Dialister invisus(均为76.92％),其后依次为纤维弯曲杆菌(61.54％),轻型链球菌(53.85％)和血链球菌(53.85％).结论 乳牙慢性根尖周病损是包含多种未培养菌的多细菌感染,与感染根管常见菌有一定关联性.
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