Bone and soft tissue outcomes, risk factors, and complications of implant‐supported prostheses: 5‐Years RCT with different abutment types and loading protocols.

Abstract: Background: Data on risk factors and complications after long‐term implant treatment is limited. The aims were to evaluate the role of various fixation modes and to analyze complications and risks that affect long‐term use of implant‐supported partial fixed dental prostheses. Materials and Methods: Fifty partially edentulous subjects received three Brånemark TiUnite™ implants. Superstructures were attached directly at implant level (IL) or via abutments: machined surface (AM) and an oxidized surface (AOX, TiUnite™). Implants were immediately loaded (test) or unloaded for 3 months (control). Examinations occurred over a 5‐year period. Results: Forty‐four subjects were re‐examined after 5 years. Cumulative survival rates in test and control groups were 93.9% and 97.0%, respectively. Marginal bone loss (MBL; Mean [SEM]) was significantly lower at superstructures connected to AM (1.61 [0.25] mm) than at sites with no abutment IL (2.14 [0.17] mm). Peri‐implantitis occurred in 9.1% of subjects and in 4.0% of implants. Multiple linear regression indicated that increased probing pocket depth (PPD), periodontal disease experience, deteriorating health, and light smoking (≤10 cigarettes/day) predict greater MBL, whereas increased buccal soft tissue thickness and higher ISQ predict lower MBL. Conclusions: The results show that MBL was influenced by the connection type. A machined abutment, instead of connecting the superstructure directly at the implant level, was beneficial. The following factors influenced MBL: PPD, periodontal disease experience, deteriorating health, light smoking, buccal soft tissue thickness, and ISQ. The results on peri‐implantitis underscore the need for long‐term maintenance care. Further, the abutment material surface properties constitute additional target for strategies to minimize MBL. [ABSTRACT FROM AUTHOR]