Abstract:
The aim of this study was to compare the fracture resistance and failure mode of non-ferruled ETT restored with different fiber post and core methods after five years in vitro fatigue loading. Forty-eight uniradicular lower first premolar teeth were decoronated, endodontically treated and prepared for the post space. The prepared specimens were divided into four groups (n=12): single fiber-reinforced composite (FRC) post and flowable resin composite core (Group I), FRC post with an accessory fiber post and flowable resin composite core (Group II), resin composite relined FRC post and resin composite core (Direct anatomic post)(Group III), and resin composite relined FRC post with an accessory fiber post and resin composite core (Direct anatomic post)(Group IV). The coronal restoration was fabricated with casted Ni-Cr alloys. All specimens were subjected to the cyclic loading test for 1.2 million cycles to simulate five years of clinical service followed by static loading test. All failure loads were recorded and statistically analyzed using one-way ANOVA at the 95% confidence level. The mode of failure was classified into two groups: favorable failure and unfavorable failure. The results showed that all specimens survived the cyclic loading test. The mean (SD) fracture resistance was 636 N (133 N) for Group I, 621 N (152 N) for Group II, 636 N (114 N) for Group III and 618 N (109 N) for Group IV. There was no statistically significant differences between different experimental groups. Ninety-six percent of specimens showed unfavorable failure. Every fiber post and core method resulted in fracture resistance above the force of mastication after five years of clinical simulation.
