Stability of the Screw Joints in Patients with Implant-Supported Fixed Prostheses in Edentulous Jaws: A 1-Year Follow-up Study

Purpose: The purpose of this follow-up study was to evaluate the stability of the screw joint in edentulous patients 1 year after treatment with implant-supported fixed prostheses (Brånemark system). Materials and Methods: A total of 20 patients were included, 10 treated in the maxilla and 10 in the mandible. The fixed prostheses were removed approximately 1 year after insertion, and the stability of the screw joints was evaluated using a rating scale based upon the CDA quality evaluation criteria of dental care. Results: All implant-supported fixed prostheses were recorded as stable before the prosthetic screws (gold screws) were unscrewed. "Unacceptable loosening" was observed in 4% of the prosthetic screws and in 29% of the abutment screws. Conclusion: In this study, only a few of the prosthetic screws showed unacceptable loosening after 1 year of function. The clinical relevance of the observed high occurrence of loose abutment screws could be questioned, as all fixed prostheses were initially recorded as stable.