In Vitro Effects of External Pressure Changes on the Sealing Ability under Simulated Diving Conditions

Aim. To measure and validate the permeability of pressure changes in correlation to different root filling techniques. Methods. Eighty extracted single-rooted teeth were randomly assigned to one of eight groups of ten teeth. Following standardized instrumentation and irrigation, root canal fillings were performed using either cold lateral condensation, a warm carrier-based gutta-percha obturation technique, a warm carrier-based Resilon, or warm gutta-percha compaction with the downpack/backfill technique. After insertion of a pressure sensor within the pulp chamber ten teeth of each group then underwent simulated dives with pressure measurement and the other ten a dye penetration test during simulated dives to 5.0 bar. Differences were analyzed statistically (P < 0.05) using one-way analysis of variance (ANOVA). Results. When the warm carrier-based gutta-percha obturation technique and vertical gutta-percha obturation techniques were used, there was significant lower intrapulpal pressure to experimental chamber pressure (P > 0.05). When cold lateral condensation or carrier-based Resilon as used, pressure was sometimes almost completely equalized. Conclusions. Warm gutta-percha obturation techniques provide a largely pressure-tight seal whereas the Resilon obturation technique and cold lateral condensation appear to be unsuitable to pressure changes.