Extraradicular infection: a methodological study

Abstract

Whether bacteria live or die in periapical lesions of endodontic origin is debated. Sampling of periapical bacteria is difficult due to possible contamination from the indigenous microflora. The aim of this study was to examine whether bacteria were present in periapical lesions of asymptomatic teeth before sampling or were transferred there during sampling. Thirty patients with root-filled teeth and periapical radiolucencies were divided into two groups, each containing 15 patients. In Group 1, a marginal incision was made to explore the periapical lesion. In Group 2, a submarginal incision was made. Before incision, the gingiva and mucosa were washed with 0.2% chlorhexidine gluconate. Bacterial samples were taken from the mucosa before reflecting the flap, and from the alveolar bone and the periapical lesion immediately after. All samples were cultured anaerobically on all-purpose and selective media. In Group 1, 12 of the 15 patients (80%) yielded bacteria from their mucosal samples despite the chlorhexidine wash. Bacterial growth was observed in all samples (100%) from the alveolar bone while the periapical lesions gave bacterial growth in 11 of 15 cases (73%). In Group 2, bacteria 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. Phenotypic profiling, performed with the data-based API bioMérieux system, indicated that the sampling technique used prevented mucosal bacteria from reaching the exposed bone and the periapical lesions. Profiling also indicated that following marginal incision, bacteria from the periodontal pocket might have reached the underlying tissues by surgeon-released bacteremia or direct translocation. Most organisms detected in the periapical lesions were clearly different from the bacteria present at neighboring sites and appeared to have been there before sampling.

Fluorescence in situ hybridization (FISH) for direct visualization of bacteria in periapical lesions of asymptomatic root-filled teeth

“…No bacteria were observed at the borders of the lesions, indicating that contamination had been prevented. This was consistent with the results of a previous methodological study of extraradicular infection where our surgical technique proved to be adequate for microbial sampling of periapical lesions (Sunde et al, 2000a).…”

“…The patients were treated with apicectomies. In Group 1 a submarginal incision was applied during surgery, while a marginal incision was made in Group 2 (Sunde et al, 2000a).…”

Development of a root canal treatment model in the rat

“…It is difficult to eliminate bacteria from root canal systems, not only because of their complex anatomical structure, but also because bacteria are embedded in biofilms. Biofilms are formed not only in the root canal system but also on the outer root surface around the apical foramen 3–5 , where they are known as extraradicular biofilms. Extraradicular biofilms lower the success rate of root canal treatment, making apical periodontitis refractory 6 .…”

Synergistic Pathogenicity of Porphyromonas gingivalis and Fusobacterium nucleatum in the Mouse Subcutaneous Chamber Model

“…Survival in such a hostile environment should be less favorable than and different from bacterial survival in the sanctuary of a necrotic root canal. Mechanisms that allow bacterial evasion of phagocytosis are most likely necessary for bacteria to either survive in this niche as a true extraradicular infection (1)(2)(3)(4) or to simply survive extraradicularly for a period long enough to be sampled as viable bacteria (5); Porphyromonas gingivalis and Fusobacterium nucleatum are among the most frequently isolated bacterial species from both chronic suppurative apical periodontitis and abscesses of dental origin (6 -9, 10). They are commonly encountered together in mixed infections associated with these conditions.…”