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. Keywords: bone preservation, crestal bone level, dental implants, surgery