The effect of apical foramen patency on condensation stresses

Abstract Mathematical models and computer-based engineering tools were used to evaluate the effect of a patent or closed apical foramen on stresses that are produced within gutta-percha during condensation. We examined a mathematical model of a tapered canal with a definite constriction and compared the results when the apical foramen was closed or open. When the canal was closed an almost constant stress was seen throughout the gutta-percha. When the foramen was open a sharp increase in lateral stress was observed in the apical portions of the canal. The constriction near the foramen caused the gutta-percha to be squeezed together and the stress was increased. This increases the likelihood that the gutta-percha is well adapted to the apical constriction. However, the stresses are also transferred to the surrounding dentin, resulting in a stress concentration near the apical foramen where the bulk of dentin is minimal.