Aerotolerance of an endodontic pathogen

The purpose of this study was to determine the length of time it takes to kill obligate anaerobic bacteria in a root canal exposed to room air or 3% hydrogen peroxide. Twenty-five extracted, human, permanent teeth with single canals were used. All teeth were contaminated with the anaerobe, Porphyromonas endodontalis (ATCC #35406), and were divided into five groups of five teeth each. Group I was exposed to 5 min of atmospheric air. Group 11 was exposed to 3% hydrogen peroxide for 5 min. Group III was exposed to 45 min of atmospheric air. Group IV was exposed to 3% hydrogen peroxide for 45 min. Group V, the control teeth, never left the anaerobic gas chamber. The results showed that atmospheric air exposure for up to 45 min is inadequate for eliminating P. endodontalis. The groups that were exposed to hydrogen peroxide showed no growth of bacteria.