Objective: This prospective randomized match-paired controlled trial aimed to evaluate the impact of implant platform diameter on marginal bone level around implants restored according to the platform switching (PS) concept.
Material and methods: A total of 24 implants were examined in 12 patients. All patients received two adjacent implants inserted at the crestal level: 4.3 mm (control group) and 4.8 mm (test group) in diameter. Mesio-distal implant position was randomly performed. According to the PS concept, for restoration, a 3.8 and 4.3 mm diameter abutment was used, respectively in the control and test groups, resulting, in both groups, with 0.25 mm of implant/abutment mismatching. Implant restorations were splinted. Eighteen months after final restoration, periapical standardized digital radiographs were taken to evaluate marginal bone level alterations after loading. The Wilcoxon Signed-Rank Test was selected to identify differences between groups.
Results: At the last follow-up, control implants exhibited a mean bone loss value of 1.10 mm (SD: 0.47 mm); the test group showed a mean value of 1.09 mm (SD: 0.08 mm). No statistically significant differences were found between test and control groups.
Conclusions: Within the limits of this study, the present results suggest that bone resorption is mostly related to biologic (biologic width re-establishment) rather than to biomechanical factors (implant platform diameter). Furthermore long-term studies with a wider sample size are needed to confirm the platform diameter influence on hard tissue response around implants restored according to the PS concept.
© 2011 John Wiley & Sons A/S.