Regina Mericske-Stern

Factors Associated with Bone Level Alterations at Implants with Inner-Cone Connection and Platform Switching

Purpose. This retrospective cohort study evaluated factors for peri-implant bone level changes (ΔIBL) associated with an implant type with inner-cone implant-abutment connection, rough neck surface, and platform switching (AT). Materials and Methods. All AT placed at the Department of Prosthodontics of the University of Bern between January 2004 and December 2005 were included in this study. All implants were examined by single radiographs using the parallel technique taken at surgery (T0) and obtained at least 6 months after surgery (T1). Possible influencing factors were analysed first using t-test (normal distribution) or the nonparametric Wilcoxon test (not normal distribution), and then a mixed model q variance analysis was performed. Results. 43 patients were treated with 109 implants. Five implants in 2 patients failed (survival rate: 95.4%). Mean ΔIBL in group 1 (T1: 6–12 months after surgery) was  mm and  mm in group 2 (T1: >12 months after surgery) (). Greater implant insertion depth in diameter 3.5 mm implants might be associated with increased ΔIBL (). In the anterior region, the bone alteration was more pronounced (). Conclusions. ΔIBL values indicated that the implant system used in this study fulfilled implant success criteria.