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.
Figure 1. Implant removal with counter-ratchet technique. (a) Clockwise insertion of the ratchet into the implant to extract. (b) Placement of the wrench to apply a torque in counterclockwise direction for implant removal. Figure 2. Removal of the implant if the countertorque exceeds the 200 Ncm. (a) Deactivation of the torque wrench. (b) The use of trephine bur to break the first 3-4 mm of implant-bone contact, the insertion of the ratchet into the implant, removal of the implant, and the insertion of new implant when a good bony support is available.
Figure 3. (a) Malpositioned implants and poor oral hygiene as indicated by the accumulation of dental plaque on the implants surface. (b) The clinical picture after receiving cleaning and polishing to improve the peri-implant soft tissue. (c) and (d) Implants with bone defects were removed and new implants were placed. The 4 implants in the anterior sector and the old prosthesis were maintained as provisional prosthesis. Figure 4. (a) Fracture of the implants at the level of the implant's neck that justifies limiting the maximum torque to a value of 200 Ncm. (b) Higher magnification.
(a) Clinical picture showing the upper removal denture and the lower overdenture. (b) Panoramic radiograph showing the evidence of bone loss around the implants supporting the lower overdenture. (c) The advanced bone loss around the implants after the reflection of mucoperiosteal flap. (d) The immediate placement of new implants and the placement of transepithelial abutment. (e) The provisional prosthesis for the implant's immediate loading. (f) Panoramic radiograph showing the newly placed implants.
(a) The implants after removing the prosthesis; we can note the puss exudate around the most mesial implant. (b) Status of the soft tissue after explantation and placement of new implants. (c) The size of the bone defect after implant removal indicated the need for regeneration and the deferral of implant placement. (d) The bone regeneration by PRGF-Endoret after 4 months were almost complete at #19 and bridged about 80% of the defect at #22. (e) Panoramic radiograph showing peri-implant bone loss around all implants before intervention. (f) The new implants supporting a new definitive prostheses.
(a) Probing depth of 8 mm around implant supported restoration. (b) Radiographic evidence of advanced peri-implant bone loss. (c) The implant removal and a circumferential bone defect. (d) The removed implant presenting dental plaque accumulation at the threaded implant neck.
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