Evaluation of fiber post-supported restorations under simulated occlusal loading

摘要

Statement of problem: There is a lack of information comparing the effect of a rigid versus flexible post on the marginal seal of post-and-core supported crowns subjected to long-term repeated loading. Purpose: The purpose of this study was to examine the leakage pattern of complete coverage restorations retained with either a metal or fiber-reinforced resin post under simulated occlusal loads. Material and methods: Thirty-six maxillary central incisors were endodontically treated and provided with a post-and-core supported crown. One group was restored with a fiber-post (EasyPost Lux) and another was restored with a metal post (Parapost) (n=12). Both groups were loaded for 120 000 cycles to 70 N while immersed in a dye solution. A control group (n=12), similarly restored with a fiber post but not loaded, was also included. All teeth were transversely sectioned serially from the tooth-core interface towards the apex. Digital photographs were made to determine the extent of leakage on the buccal, mesial, palatal, and distal aspects along the depth of the post. A nonparametric Kruskal-Wallis test was used to determine any difference between groups (α=.05). Results: Dye penetration occurred in all stress-cycled specimens and was more extensive on the palatal than other aspects. The fiber-post group cyclically stressed to 70 N showed a significantly greater amount of leakage than the control or the Parapost group (P<.05). Conclusions: In in vitro testing, the rigidity of the post influenced the seal of post-and-core-supported crowns at the palatal margin.