Behavior of mineral trioxide aggregate apical plugs and root fillings under cyclic loading.

AIM: The aim of the present study was to develop a methodology for constant monitoring of the resistance to fluid flow during functional loading and to then compare the efficacy of 4-mm mineral trioxide aggregate (MTA) apical plugs and full-length MTA root fillings. METHODS: The root canals of 24 single-rooted teeth were instrumented and assigned into two groups: group 1 (filled with a 4-mm MTA apical plug and gutta percha) and group 2 (filled with MTA to cementoenamel junction level). All teeth were subjected to stepwise cyclic loading with a constant simulated interstitial pressure of 25 cm H(2) O applied apically. A Flodec machine (De Marco Engineering, Geneva, Switzerland) constantly monitored the rate and direction of fluid flow. Student's t-test, Kruskal-Wallis test, Fisher's exact test, and Newcombe-Wilson test were used for statistical analysis, with P < 0.05. RESULTS: Crown fractures occurred in 21 teeth with no change in the rate of fluid flow. Three teeth (filled with full-length MTA) showed sudden change in the rate of fluid flow through the root canal after cyclic loading. CONCLUSIONS: The methodology reliably monitored fluid flow during cyclic loading. There was no difference between a 4-mm MTA apical plug and full-length MTA root filling after cyclic loading using a dynamic fluid-flow monitoring technique.