Influence of Abutment Configuration on the Fatigue Survival of Titanium Implant–Abutment Assemblies

Fatigue performance of implant-supported assemblies depends on both loading conditions and structural configuration. This study investigated whether abutment configuration influences fatigue survival in titanium implant–abutment assemblies after accounting for cyclic load magnitude. Thirty-six internal-connection assemblies representing four configurations (n = 9 each) were tested under cyclic loading according to ISO 14801. Cycles to fracture or test termination were analyzed using Cox proportional-hazards regression, with non-fractured specimens treated as right-censored and maximum cyclic load (Pmax) included as a covariate. Twenty-three specimens fractured and 13 were right-censored. Each 10 N increase in Pmax was associated with a 2.52-fold higher fatigue hazard (95% CI, 1.75–3.62; p < 0.001). Abutment configuration had a significant overall effect after load adjustment (p = 0.027). Compared with the reference configuration (MUSA 04010), MUSLA 04020 showed a higher fatigue hazard (HR = 10.89; 95% CI, 2.23–53.33; p = 0.003). After multiplicity correction, MUSLA 04020 also showed a higher fatigue hazard than MUSA 04050 and MUSLA 04060, whereas no significant differences were found among MUSA 04010, MUSA 04050, and MUSLA 04060. The principal association remained consistent in sensitivity and leave-one-out analyses. Fatigue survival was therefore configuration-dependent within the tested system and should not be attributed to transmucosal height alone. Specimen-level, censoring-aware survival modelling can complement conventional fatigue descriptors in standardized implant fatigue testing.