Department of Endodontics and Operative Dentistry, School of Stomatology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai.
Int Endod J. 2009 Dec;42(12):1096-103. doi: 10.1111/j.1365-2591.2009.01639.x.
To investigate, by reverse transcription polymerase chain reaction (RT-PCR), the presence and association of bacteria and archaea in primary and secondary root canal infections.
A total of 77 root canal samples from 77 Chinese patients, 42 with necrotic pulp tissues (primary infection) and 35 with failed prior conventional root canal treatment (secondary infection), aseptically exposed at the first patient visit, were studied. Total RNA was isolated directly from each sample, and 16S rRNA gene-based RT-PCR assays were used to determine the presence of bacteria and archaea, respectively.
Bacteria were detected in 39/42 (93%) of root canal samples from teeth with primary infections, and archaea in 16/42 (38%). In the cases diagnosed as secondary root-infected canals, bacteria were detected in 30/35 (86%), whilst archaea were detected in 6/35 (17%) of cases. Amongst the canals, which were positive for bacteria, archaea were always found in combination with bacteria. The incidence of symptomatic cases positive for both bacteria and archaea (16/22, 73%) were significantly higher than those positive for bacteria alone (21/47, 45%) (P < 0.05).
This study confirms the presence of archaea in root canal infections and further implicates them in an association with clinical symptoms. The nature of this association requires further study.
通过逆转录聚合酶链反应（RT-PCR）检测原发性和继发性根管感染中细菌和古菌的存在和相关性。
共研究了 77 例来自 77 例中国患者的根管样本，其中 42 例有坏死牙髓组织（原发性感染），35 例为先前常规根管治疗失败（继发性感染）。在首次就诊时无菌暴露后，直接从每个样本中分离总 RNA，并分别使用基于 16S rRNA 基因的 RT-PCR 检测来确定细菌和古菌的存在。
在 39/42 例（93%）原发性感染根管样本中检测到细菌，在 16/42 例（38%）中检测到古菌。在诊断为继发性感染根管的病例中，在 30/35 例（86%）中检测到细菌，而在 6/35 例（17%）中检测到古菌。在阳性的根管中，古菌总是与细菌一起存在。同时检测到细菌和古菌的有症状病例（16/22，73%）的发生率明显高于仅检测到细菌的病例（21/47，45%）（P<0.05）。
本研究证实了古菌存在于根管感染中，并进一步表明它们与临床症状有关。这种关联的性质需要进一步研究。
