Implant survival and prosthetic complications of mandibular metal-acrylic resin implant complete fixed dental prostheses

Statement of purpose This study examined and recorded the long-term implant survival and prosthetic complications of patients treated with mandibular metal-acrylic resin implant complete fixed dental prostheses delivered in a private practice setting over a 22-year period. Material and methods Records were examined for all patients in the authors' private prosthodontic practices who between April 1988 and April 2011 had received mandibular metal-acrylic resin implant complete fixed dental prostheses supported by 4 to 8 implants and who had completed at least 1 year of follow-up after implant placement. Results Forty-five patients who had received a total of 247 implants met the inclusion criteria. In the course of the 1- to 22-year follow-up period (mean 8 years and 3 months), only 2 implants failed (0.81%) in 1 patient before definitive prosthetic reconstruction, which resulted in a cumulative implant survival rate of 97.78% ±2.2%. No screws were found to be loose or fractured. Individual denture-tooth fracture and chairside repair occurred 10 times in 5 patients. Because of wear, all the teeth had to be replaced by the laboratory 10 times in 8 patients between 5 and 12 years. Framework fractures occurred 6 times and affected 3 prostheses (twice for each of the 3 patients). Conclusions Implant failure was rare with this traditional mode of treatment and occurred before definitive restoration. The replacement of denture teeth due to wear or fracture was the most common prosthetic complication, and cantilevered frameworks exhibited a high risk of fracture when opposed by fixed prostheses. No fractures occurred for any of the frameworks opposed by complete dentures or removable implant prostheses.