Periimplant bone level around implants with platform-switched abutments

Objectives: Several long-term clinical studies demonstrated a mean marginal bone loss around dental implants of 1.2 -1.5 mm in the first year after prosthetic restauration. The use of prosthetic abutments with reduced diameters in relation to the implant diameter (platform-switching) seems to have the potential to limit the crestal resorption. The purpose of this clinical trial was to evaluate, if the crestal bone height around dental implants could be influenced using a platform-switch protocol. Methods: 10 patients were treated with fixed implant retained prosthesis. Standardized digital radiographs were taken for evaluation of marginal bone levels at the time of the installation of the restoration and at 1-year follow-up. Marginal periimplant bone levels were measured at the mesial and the distal surface of each implant using digital image analysis and digital subtraction radiography. Results: The mean value of crestal bone height loss at the 1-year follow up was 0.2 ± 0.4 mm for the platform-switched implants and 1.2 ± 0.3 mm for the non-platform-switched implants, and when tested with repeated-measure ANOVA, the differences were statistically significant (p ? 0.05). Conclusion: The concept of platform-switching appears to limit the crestal resorption and seems to be able to preserve the periimplant bone levels. The reduction of the abutment of 0.45 mm on each side (5 mm implant/ 4.1 mm abutment) seems sufficient to avoid periimplant bone loss. The study was supported in part by 3i Implant Innovations.