Peri-implant bone loss around platform-switched Morse taper connection implants: a prospective 60-month follow-up study

The aim of this study was to measure the crestal bone level changes at 60 months of follow-up and to evaluate the influence of biologically relevant, anatomical, and implant-related variables. A prospective study design was used. STROBE guidelines were followed. A total of 576 implants were inserted in 270 patients needing an implant-supported, partial, fixed dental prosthesis or a single crown. Standardized peri-apical radiographs were obtained at 2 months (time of implant-abutment connection and prosthetic loading) and 60 months of follow-up. Descriptive statistics were used and inter- and intra-examiner reliability determined. A mixed model was used to evaluate the predictor variables. The correlation among multiple implants inserted in a single patient was considered. Significance was assessed using the type 3 test. Sensitivity analyses, least-squares means analyses, t-tests, and χ(2) tests were also conducted. The statistical analysis was performed at the implant level; P<0.05 indicated statistical significance. At the 60-month follow-up, the mean marginal bone remodelling was -0.59±1.34mm (range -5.70 to 3.65mm). Marginal bone loss was significantly influenced by implant depth, implant location, and the interactions implant depth×jaw, implant location×timing of implant placement, and jaw×implant diameter. At the 60-month follow-up, a low mean marginal bone loss was found, which was significantly higher with subcrestal implants and anterior implants.