Crestal Bone Level Around Tissue-Level Implants Restored with Platform Matching and Bone-Level Implants Restored with Platform Switching: A 5-Year Randomized Controlled Trial.

PURPOSE: The aim of this randomized clinical trial with a 5-year follow-up was to assess the differences in radiographic levels of peri-implant bone crest between tissue-level implants restored with platform matching (control group) and bone-level implants restored with platform switching (test group) in the posterior region. MATERIALS AND METHODS: To assess marginal bone level changes, periapical radiographs were taken at the moment of prosthesis delivery (baseline), at 1 year, and at 5 years after the definitive restoration. RESULTS: One hundred subjects, partially edentulous in the posterior region, were selected for this study. There were 54 men and 46 women between the ages of 25 and 70 years (mean = 50.5 years). A total of 202 implants were assigned to both groups using a randomized procedure (100 implants in the control group and 102 in the test group). The mean marginal bone level (MBL) changes for tissue-level implants restored with platform matching were 0.26 +/- 0.55 mm at baseline to 1 year, 0.34 +/- 0.54 mm at 1 year to 5 years, and 0.61 +/- 0.73 mm at baseline to 5 years. The mean MBL changes for bone-level implants restored with platform switching were -0.03 +/- 0.74 mm at baseline to 1 year, -0.17 +/- 0.67 mm at 1 year to 5 years, and -0.20 +/- 0.75 mm at baseline to 5 years. The mean difference between the two groups was 0.31 mm at baseline to 1 year, 0.53 mm at 1 year to 5 years, and 0.85 mm at baseline to 5 years. There was a statistically significant difference in MBL (P < .001). Both implant systems showed good and similar survival rates (98% for tissue-level implants restored with platform matching and 96.1% for bone-level implants restored with platform switching). CONCLUSION: In this randomized controlled trial, the following observations were made. Radiographic levels of peri-implant bone crest in tissue-level implants restored by platform matching were statistically significant in the three interval times. Meanwhile, MBL changes for bone-level implants restored with platform switching were not statistically significant in the different times studied. Nevertheless, the mean difference between the two groups was statistically significant.