Clinical and Radiographic Evaluation of Zirconia Bars for Mandibular Implant Overdentures: A Prospective Cohort Study With up to 3 Years of Follow-Up

Abstract

Purpose: To assess the clinical and radiographic outcomes of computer-aided design–computer-assisted manufacturing (CAD-CAM) zirconia bars supporting mandibular implant overdentures (IODs) up to a follow-up period of 3 years. Materials and Methods: A prospective cohort observational single-center study involving 30 edentulous patients rehabilitated with two dental implants (Ø4.3 × 10 mm) at the crestal bone level and an IOD supported by a zirconia bar with distal extensions (maximum length 10.6 mm). At the 1- and 3-year follow-up, implant, prosthetic survival, marginal bone level (MBL) changes, biological, and technical complications were recorded. Results: A total of 25 patients were assessed at the 12-month (dropout of 19.4%), and 14 patients completed the 36- month follow-up (dropout of 54.8%). Implant survival and success rates were both 100%, while prosthetic survival was 100% with a success rate of 96%. No biological complications were observed during the follow-up period; however, one patient exhibited generalized mucosal hyperplasia around the zirconia bar at the 12-month evaluation. No prosthetic prosthodontic maintenance needs were reported. A mean marginal MBL of −1.28 mm (SD ± 0.37) was recorded at the initial 12-month follow-up, and − 1.32 mm (SD ± 0.32) at the 36-month follow-up. The difference in MBL between the two time points was not statistically significant (p = 0.529). Conclusion: Zirconia bars with distal extensions for mandibular IODs appear to be a reliable treatment option for the rehabilitation of edentulous patients, demonstrating favorable clinical outcomes up to 3 years of follow-up. A 100% implant and prosthetic survival rate was achieved, along with stable MBLs. Clinicaltrials.gov identifier: NCT06471881.