What Are the Incidence and Factors Associated With Implant Fracture?
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© 2017 American Association of Oral and Maxillofacial Surgeons Purpose Implant fracture is a serious complication, which leads to treatment failure. The purpose of this study is to estimate the incidence of implant fractures and identify factors associated with them. Materials and Methods In this retrospective cohort study, the sample was derived from 2 implant centers. The predictors were grouped into the following categories: demographic, location of implant, physical characteristic of implant, implant-abutment connection, type of prosthesis, type of retention, and outcome variable (time to implant fracture). The Kaplan-Meier test was used to estimate implant survival. A Cox regression model was applied to evaluate the time-to-event effect of variables on implant fracture. Results Of 18,700 implants, 37 (0.002%) had fractures. The 1- and 5-year risk of implant fracture was 0.38 per 1,000 and 1.46 per 1,000, respectively. Implant fractures more often occurred in the premolar and molar area (94.6%) than in the anterior of the jaws. The Pearson correlation test did not show any correlation between age, implant diameter, or implant length and time of fracture (P > .05). Analysis of the data by the log-rank test showed a significant difference for survival between cemented and screw-retained crowns (P =.001). The Cox regression model showed a hazard ratio of 0.23 for tapered implants versus cylindrical fixtures and for screw-retained crowns (hazard ratio, 296.54) versus cemented crowns. Conclusions According to this study, conical implants and screw-retained prostheses may have lower survival rates due to implant fracture.