Impact of platform switching on inter-proximal bone levels around 8.5 mm implants in the posterior region; 5-year results from a randomized clinical trial

Aim: To assess the medium- term results of 8.5 mm implants supplied with a conventional platform- matched implant- abutment connection or a platform- switched design.

Materials and Methods: Eighty patients with one or more missing teeth in the maxillary or mandibular posterior zone were randomly assigned for treatment with implants with a conventional (control group) or platform- switched (test group) implant- abutment connection. Follow- up visits were conducted 1 month, 1 year and 5 years after functional loading. Inter- proximal bone loss, assessed with standardized peri- apical radiographs, clinical parameters, survival of implants and satisfaction of patients were the outcome parameters studied.

Results: After 5 years of loading, five of the 80 patients were lost to follow- up. The inter- proximal bone loss in the test group (0.38 +/- 0.61 mm) was comparable to the bone loss in the control group (0.41 +/- 0.47 mm; p = 0.201). Remarkably, bone loss has not progressed compared to the 1-year results. Implant survival, clinical parameters and satisfaction of the patients were favourable and comparable for the test and control group.

Conclusion: The 5-years results showed that inter-proximal bone resorption was minor and comparable around platform-matched and platform-switched implants, and implant survival, peri-implant health and patients' satisfaction were favourable.