中文摘要：

目的 研究慢性根尖周炎感染根管中微小小单胞菌的检出率及其与牙髓优势致病菌检出之间的相关性,探讨该菌在慢性根尖周炎感染根管中的定植情况.方法 采集104例慢性根尖周炎患者的120颗患牙根管内标本,其中包括慢性根尖周炎初次治疗组和再次治疗组（患牙需经根管治疗2年以上,X线片表现为患牙根管充填不完善,根尖周病变不愈合或出现新的根尖周病变）,两组各60颗患牙（初次治疗组47例,再次治疗组57例）.利用菌种特异性引物16S rDNA PCR法检测标本中的微小小单胞菌DNA,并计算其检出率.利用Logistic回归分析（OR直）方法分析该菌与粪肠球菌、牙髓卟啉单胞菌和牙龈卟啉单胞菌之间的相关性.结果 在慢性根尖周炎初次治疗组中微小小单胞菌的检出率为40％（24/60）,再次治疗组中微小小单胞菌的检出率为5％（3/60）.两组间差异有统计学意义（X^2=21.06,P＜0.05）.Logistic回归分析结果显示,在慢性根尖周炎初次治疗组（OR=5.98）和再次治疗组（OR=33.50）中微小小单胞菌与牙髓卟啉单胞菌之间均具有相关性,与粪肠球菌和牙龈卟啉单胞菌之间无相关性.结论 微小小单胞菌为慢性根尖周炎感染根管微生态环境中的组成菌之一,与牙髓卟啉单胞菌的定植之间可能存在共生关系.

英文摘要：

Objective To study the prevalence of Parvimonas micra（Pm） and the associations between Pm and pulp dominant pathogens in order to reflect the colonization of Pm in the infected root canals with chronic periradicular periodontitis.Methods A total of 120 teeth diagnosed as chronic periradicular periodontitis from 104 patients were included into the study.The teeth were allocated into untreated （primary infectious） and root-canal-treated （secondary infectious） groups with 60 in either group.Samples were collected from the root canals using sterile files and paper points,and subsequent extraction of bacterial DNA was undertaken.The Pm 16S rDNA level was evaluated using 16S rDNA PCR.The prevalence of Pm in chronic periradicular periodontitis was determined accordingly.Then,the associations of Pm and Enterococcus faecalis（Ef）,Porphyromonas endodontalis（Pe） as well as Porphyromonas gingivalis （Pg） were analysed.Results Pm was detected in 40% （24/60） of the samples from the primary infectious group,5% （3/60） from the secondary infectious group.The prevalences of Pm from the two groups were different significantly （x2=21.06,P〈0.05）.Significant correlations （untreated group OR=5.98,root-canaltreated group OR=33.50） between Pm and Pe were identified in both groups,while the correlations between Pm and Pg as well as Ef were not of significance,respectively.Conclusions A significantly higher relevance ratio of Pm was estimated in the primary infectious group than the secondary infectious one.Pm and Pe were correlated significantly in the infected root canals,suggesting a symbiotic relation between these two bacteria.