The Effect of Healing Abutment Reconnection and Disconnection on Soft and Hard Peri-implant Tissues: A Short-Term Randomized Controlled Clinical Trial

Purpose: It has been reported that multiple abutment disconnections and reconnections following implant placement may compromise the peri-implant mucosal seal and may lead to increased marginal bone loss. Thus, the aim of this study was to evaluate the effect of healing abutment disconnection and reconnection on soft and hard peri-implant tissues. Materials and Methods: Sixteen patients were included in this prospective randomized controlled clinical trial. Following one-stage implant placement, test group implants (n = 10) received a permanent abutment and control group implants (n = 11) received a healing abutment. After 2 months of healing, control group implants underwent a prosthetic protocol involving implant-level impressions and a two-time abutment disconnection and reconnection process prior to delivery of the definitive prosthesis. Test group implants underwent a prosthetic protocol involving abutment-level impressions without any abutment disconnection. Clinical parameters were recorded at 2 weeks, 2 months, 3 months, and 6 months, and marginal bone levels were assessed radiographically at implant placement, 3 months, and 6 months. Results: The overall survival rate from implant placement to the last follow-up visit was 100% for both groups. The mean marginal bone loss at the 6-month examination was 0.13 mm for test group implants and 0.28 mm for control group implants. There were no significant differences regarding changes in periimplant mucosal dimensions between the two groups. Conclusion: The present study indicates that implants receiving a final abutment at the time of implant placement exhibited minimal marginal bone loss and were similar to implants subjected to abutment disconnection and reconnection two times. Disconnection and reconnection of the abutment two times did not cause negative dimensional changes in the peri-implant mucosa.