Replacement of maxillary and mandibular molars with single endosseous implant restorations: a retrospective study

This retrospective report presents findings on 22 patients with 24 implants replacing single molars with implant-supported restorations. Patients with known bruxism habits were not considered for single-molar implant replacement. The patients underwent follow-up for an average of 24 months. The cumulative success rate was 95%, which reflects the loss of one 5 x 6 mm wide implant. Eleven implants were placed in edentulous ridges, and 13 were placed in extraction sockets. Most of the implants were placed in type B and C bone quantity and type 2 and 3 bone quality. All implants were restored on abutments with nonrotating gold cylinders. The occlusion for all restorations was developed to minimize centric contacts and lateral interferences. The frequency of gold retaining-screw loosening was obtained for 21 patients. The gold retaining screws loosened in eight implants between one and three times (38%). No incidence of crown or implant fracture occurred. Within the limits of this study, replacement of single-tooth molars by implant-supported restorations was predictable; however, a high incidence of gold screw loosening was seen.