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

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.

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.

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).

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.