Extraradicular infection: a methodological study

Whether bacteria live or die in periapical lesions of endodontic origin is debated. Sampling of periapical bacteria is difficult due to possible conta mination from the indigenous microflora. The aim of this study was to exami ne whether bacteria were present in periapical lesions of asymptomatic teet h before sampling or were transferred there during sampling. Thirty patient s with root-filled teeth and periapical radiolucencies were divided into tw o groups, each containing 15 patients. In Group 1, a marginal incision was made to explore the periapical lesion. In Group 2, a submarginal incision w as made. Before incision, the gingiva and mucosa were washed with 0.2% chlo rhexidine gluconate. Bacterial samples were taken from the mucosa before re flecting the flap, and from the alveolar bone and the periapical lesion imm ediately after. AU samples were cultured anaerobically on all-purpose and s elective media. In Group 1, 12 of the 15 patients (80%) yielded bacteria fr om their mucosal samples despite the chlorhexidine wash. Bacterial growth w as observed in all samples (100%) from the alveolar bone while the periapic al lesions gave bacterial growth in 11 of 15 cases (73%). In Group 2, bacte ria were cultured from the mucosa in 11 of 15 (73%) patients. Three samples (20%) from the alveolar bone and 10 from the periapical lesions (67%) gave positive growth. The predominant cultivable bacteria were anaerobic. Pheno typic profiling, performed with the data-based API bioMerieux system, indic ated that the sampling technique used prevented mucosal bacteria from reach ing the exposed bone and the periapical lesions. Profiling also indicated t hat following marginal incision, bacteria from the periodontal pocket might have reached the underlying tissues by surgeon-released bacteremia or dire ct translocation. Most organisms detected in the periapical lesions were cl early different from the bacteria present at neighboring sites and appeared to have been there before sampling.