Conservative Implant Removal for the Analysis of the Cause, Removal Torque, and Surface Treatment of Failed Nonmobile Dental Implants

This study was performed to study the effect of implant surface treatment on the cause and removal torque of failed nonmobile implants. Implant explantation was achieved by the application of countertorque at the implant bone interface. The explantation socket was examined carefully and curetted to remove any granulation tissue. Immediate implant placement was accomplished when primary stability could be achieved. Eighty-one patients were treated according to the described treatment protocol for the explantation of 158 nonmobile implants in the maxilla and the mandible. The patient's mean age was 62 +/- 11 years. The main cause of implant explantation was peri-implantitis (131 implants; 82.9%) followed by malpositioning of the implants (22 implants; 13.9%). The explantation of 139 implants at 146 +/- 5 Ncm was performed without the need for trephine bur. However, the use of trephine burs to cut into the first 3 to 4 mm was necessary in 19 explantations, and the removal torque was 161 +/- 13 Ncm. All titanium plasma-sprayed implants were removed due to peri-implantitis at a significantly lower torque when compared to acid-etched, particle-blasted, and oxidized implants. The postoperative recovery of the patients was uneventful and the conservation of the available hard and soft tissues was successfully achieved. The protocol followed in this study could constitute a real alternative to other traumatic technique for the removal of failed implants and advanced stages of peri-implantitis. The type of implant surface treatment could influence the value of removal torque and the occurrence of peri-implantitis.