A Prospective Multicenter Study on Radiographic Crestal Bone Changes Around Dental Implants Placed at Crestal or Subcrestal Level: One-Year Findings

Purpose: To compare the peri-implant radiographic crestal bone changes around implants placed at the subcrestal or crestal level. Materials and Methods: Systemically healthy patients with at least two missing teeth requiring implant-supported fixed prosthetic restorations were enrolled in the study. Implants were randomly placed either 1 mm subcrestally or at the bone crest level. Radiographic examination was performed using the long-cone parallel technique and customized film holders. Digital periapical radiographs were obtained at the time of implant placement (T0), at the time of prosthesis delivery (T1), and 12 months (T2) after prosthetic loading. Marginal bone levels were measured at the mesial and distal aspects of each implant with digital image software. Results: A total of 54 implants were present for the radiographic analysis at the 12-month follow-up. No implant showed mechanical or biologic complications throughout the follow-up period. The implant survival percentage was 100%. After 1 year, the mean bone loss was 0.711 ± 0.721 mm in the subcrestal group and 0.224 ± 0.418 mm in the crestal group. Furthermore, only the subcrestal group showed statistically significant radiographic bone resorption at the end of the follow-up. Conclusion: Within the limitations of this study, implants placed at the crestal level showed greater peri-implant bone stability during the 1-year follow-up. Studies with larger samples and longer follow-up are needed to confirm the results of this investigation.