Department of Restorative Dentistry, Division of Endodontics, Piracicaba Dental School, State University of Campinas - UNICAMP, Av. Limeira 901. Bairro Areao, Piracicaba, SP, Brazil.
Faculty of Medical Sciences, University Center Lusíada - UNILUS, Santos, SP, Brazil.
Clin Oral Investig. 2021 Nov;25(11):6249-6258. doi: 10.1007/s00784-021-03923-7. Epub 2021 Apr 12.
Fusobacterium nucleatum is an important oral pathogen involved in endodontic infections. This study aimed to assess the frequency of Fusobacterium nucleatum in primary and secondary endodontic infections and its associations with the clinical features in a Brazilian population by using both culture and nested PCR methods.
A total of 100 microbial samples from patients with primary (n=50) and secondary endodontic infections (n=50) were analyzed by using culture and nested PCR methods. Strict anaerobic techniques were used for culture and identification of F. nucleatum. The DNA extracted from the samples was analyzed for the presence of target species by using species-specific primers.
Culture and nested PCR methods detected F. nucleatum, respectively, in 11/100 and 82/100 root canals. F. nucleatum was isolated by culture from 10/50 (20%) root canals with primary infections and from 1/50 (2%) root canal with secondary/persistent infections. Nested PCR detected F. nucleatum in 42/50 (84%) root canals with primary infections and in 40/50 (80%) root canals with secondary/persistent endodontic infections. F. nucleatum was associated with spontaneous pain, tenderness to percussion, pain on palpation, swelling, tooth mobility, wet root canals, hemorrhagic exudate, tooth decay, inadequate restoration, and poor endodontic filling.
F. nucleatum was found in more cases of primary endodontic infections than in cases of secondary/persistent ones. A higher prevalence of F. nucleatum was detected by using the nested PCR method than by using culture. The presence of F. nucleatum in the root canals was associated with several clinical features.
The high prevalence of F. nucleatum in the root canals detected by molecular methods, and its association with several clinical features reveals the importance of these species in the development of apical pathologies and reinforces the need of an endodontic treatment directed to bacterial elimination.
具核梭杆菌是一种重要的口腔病原体，与根管感染有关。本研究旨在通过培养和巢式 PCR 方法评估具核梭杆菌在巴西人群原发性和继发性根管感染中的频率及其与临床特征的关系。
采用培养和巢式 PCR 方法分析 100 例原发性（n=50）和继发性根管感染（n=50）患者的 100 个微生物样本。采用严格的厌氧技术进行培养和具核梭杆菌鉴定。从样本中提取的 DNA 用种特异性引物分析目标种的存在。
培养和巢式 PCR 方法分别在 100 个根管中检测到具核梭杆菌 11/100 和 82/100。培养法从 50 个原发性感染根管中分离出 10/50（20%）的具核梭杆菌，从 50 个继发性/持续性感染根管中分离出 1/50（2%）的具核梭杆菌。巢式 PCR 检测到 42/50（84%）的原发性感染根管和 40/50（80%）的继发性/持续性根管感染中存在具核梭杆菌。具核梭杆菌与自发性疼痛、叩诊压痛、触诊疼痛、肿胀、牙齿松动、湿根管、血性渗出物、龋齿、修复不当和不完善的根管填充有关。
与继发性/持续性根管感染相比，原发性根管感染中发现具核梭杆菌的病例更多。巢式 PCR 法检测到的具核梭杆菌的患病率高于培养法。根管中具核梭杆菌的存在与几种临床特征有关。
分子方法检测到的根管中具核梭杆菌的高患病率及其与几种临床特征的关系表明，这些物种在根尖病变的发展中具有重要性，并加强了针对细菌消除的根管治疗的必要性。
