Siqueira José F, Rôças Isabela N
Department of Endodontics, Faculty of Dentistry, Estácio de Sá University, Rio de Janeiro, RJ, Brazil.
J Endod. 2004 Mar;30(3):135-7. doi: 10.1097/00004770-200403000-00002.
In recent years, molecular genetic methodologies have provided significant additional knowledge about components of the microbiota associated with infections of endodontic origin. Following this research line, the purpose of the present study was to investigate the prevalence of Centipeda periodontii in primary endodontic infections using a species-specific nested PCR assay. Samples were collected from fifty teeth having carious lesions, necrotic pulps, and different forms of periradicular diseases. DNA extracted from the samples was initially amplified using universal 16S rDNA primers, and a second round of amplification used the first PCR products to detect a specific fragment of C. periodontii 16S rDNA. This species was detected in 3 (13%) of 23 asymptomatic cases, in 1 (14%) of 7 cases diagnosed as acute apical periodontitis, and in 3 (15%) of 20 pus samples aspirated from acute periradicular abscesses. There was no significant association between C. periodontii and the presence of clinical symptoms. Overall, C. periodontii was detected in 14% of the cases of endodontic infections. This is probably the hitherto first study to detect C. periodontii in primary endodontic infections. The specific role played by this bacterial species in infections of endodontic origin awaits further clarification.
近年来，分子遗传学方法为牙髓源性感染相关微生物群的组成提供了重要的补充知识。沿着这条研究路线，本研究的目的是使用种特异性巢式PCR检测法，调查牙周千根草在原发性牙髓感染中的患病率。从50颗患有龋损、牙髓坏死和不同形式根尖周病的牙齿中采集样本。从样本中提取的DNA首先使用通用16S rDNA引物进行扩增，第二轮扩增使用第一轮PCR产物来检测牙周千根草16S rDNA的特定片段。在23例无症状病例中有3例（13%）检测到该菌种，在7例诊断为急性根尖周炎的病例中有1例（14%）检测到，在从急性根尖周脓肿抽出的20份脓液样本中有3例（15%）检测到。牙周千根草与临床症状的存在之间没有显著关联。总体而言，在14%的牙髓感染病例中检测到牙周千根草。这可能是迄今为止首次在原发性牙髓感染中检测到牙周千根草的研究。该细菌物种在牙髓源性感染中所起的具体作用有待进一步阐明。
