The Use of Extraoral Implants for Distal-Extension Removable Dentures: A Clinical Evaluation Up to 8 Years

Purpose: This retrospective study reports the clinical outcome following placement of extraoral implants in severely resorbed posterior ridges to support distal-extension removable dentures. Material and Methods: Consecutively treated patients with partially or completely edentulous ridges, with available bone height in the posterior region of 6 mm or less, were included in the study. Implants originally intended for extraoral use (Straumann) were placed in second molar regions and allowed to heal for 4 to 6 months before abutment connection. At recall appointments, the peri-implant hard and soft tissues were evaluated. Complications with implant components, as well as mechanical and structural failures of the prostheses, were recorded. Two-year survival rates were calculated and life table analyses undertaken. Results: Twenty-nine patients (19 women and 10 men; average age 61.2 years, range, 44 to 75 years) were included in the study. Forty-seven extraoral implants in 26 patients were placed in the second molar site of the mandible. Two extraoral implants in 2 patients failed during the osseointegration phase, yielding an 8-year cumulative success rate of 91.8%. The mean distance from the extraoral implants to the most distal tooth/implant was 28.1 mm (range, 16.7 to 39.2 mm). Twenty-three extraoral implants were restored with magnets, 18 with ball anchors, and 4 with conical cylinders. Replacement of abutments and retention elements was necessary in 2 patients. Four abutments in 2 patients were disconnected from the restorations. Conclusions: Within the limits of the employed research design, extraoral implants may be used successfully to provide support for distal-extension removable dentures in severely resorbed posterior alveolar ridges. Keywords: alveolar atrophy, extraoral implant, life table analysis, posterior alveolar ridge, submerged implants