Risk factors associated with post-loading implant loss of removable and fixed implant-supported prostheses in edentulous jaws.

PURPOSE: This study analyzed risk factors for post-loading implant loss in cases of implant-supported prostheses applied to edentulous jaws of Japanese patients. METHODS: In total, 245 dental implant fixtures placed in 54 edentulous jaws of 46 patients performed at Niigata University Hospital were retrospectively analyzed. Kaplan-Meier curves were used to estimate the cumulative survival rate (SR) of implants, and multiple Cox regression analysis was used to identify predictive factors of implant loss. The following risk factors for implant failure were examined: age, sex, survival time, implant length, implant location, smoking habit, bone density, bone augmentation, opposing dentition, loading period, and type of final restoration. The Cochran-Mantel-Haenszel test was used to examine difference in survival curves of the extracted predictors. RESULTS: Sixteen implants failed during the observation period (SR=92.8 %). Multiple Cox regression analysis revealed that male sex [hazard ratio (HR)=16.1; p=0.007] and use of maxillary removable restorations (HR=12.7; p<0.000) were risk factors for implant failure. Other factors had no significant effect on implant failure. The SR of implants for males (SR=86.9%) was significantly lower than that for females (SR=99.1%). The SR of implants for maxillary removable restorations (SR=76.4%) was significantly lower than for maxillary fixed restorations (SR=99.1%) and mandibular fixed restorations (SR=97.8%). CONCLUSIONS: Maxillary implants with removable restorations and male sex were risk factors for implant failure among Japanese edentulous patients.