关键词: 牙髓卟啉单胞菌, 具核梭杆菌, 中间普氏菌, 粪肠球菌, 16S rDNA

Abstract:

Objective　To detect colonization of four anaerobic bacteria in infected root canals with 16S rDNA-PCR. Methods　Thirty freshly extracted teeth were selected for this study （10 teeth with pulpitis; 10 teeth with periapical lesions; 10 teeth with failed root canal treatment）. Each root canal was divided into two sections：the corona and middle section （6 mm to root tip），and the tip section （3 mm to root tip）. Bacterial genomes of every section were extracted，and classes of bacteria were detected with 16S rDNA-PCR；the detection rate was calculated and statistical analysis was made. Results　P.endodontalis （P.e），F.nucleatum （F.n） ，E.faecalis（E.f）and P.intermedia （P.i） were detected in corona and middle section of pulpitis group，with P.e detected in most canals（P＜0.05），while only P.e was detected in the tip section. In group of periapical lesions，no statistically significant difference was found in the detection rate of P.e，F.n，P.i or E.f（P > 0.05）. In group of failed root canal treatment，detection rate of E.f in the tip section （60%） was higher than that in the corona and middle section （10%），with obvious statistical difference （P < 0.05）. Conclusion　Colonization of anaerobic bacteria of pulpitis canals is mostly in the corona and middle section，with the highest detection rate in P.e. In periapical inflammation canals，no statistically significant difference is found  in the detection rate of P.e，F.n，P.i or E.f，with P.i as the main bacteria. In endodontic treatment failure canals，E.f is the main bacteria，and is most often detected in the tip section.

Key words: P.endodontalis, P.e；F.nucleatum, F.n；P.intermedia, P.i；E.faecalis, E.f；16S rDNA