Monolithic Zirconia Versus Porcelain-Fused-to-Metal Implant-Supported Fixed Dental Prostheses in the Posterior Region: 3-Year Results of a Randomized Controlled Clinical Trial.

OBJECTIVES: To compare the clinical, biological, and technical outcomes of posterior three-unit implant-supported fixed dental prostheses (iFDPs) fabricated from monolithic zirconia (MonoZR) or porcelain-fused-to-metal (PFM). MATERIALS AND METHODS: In this prospective randomized controlled trial, partially edentulous patients requiring a posterior three-unit iFDP supported by two implants were randomly assigned to MonoZR or PFM iFDPs. The primary outcome was ceramic fracture. Secondary outcomes included prosthesis survival, complication-free survival, marginal bone level (MBL) changes, peri-implant clinical parameters, and USPHS ratings. Follow-up examinations were performed at 1 and 3 years. Statistical analyses included Kaplan-Meier estimates, Fisher's exact test, and linear mixed-effects models (α = 0.05). RESULTS: Fifty-five patients received iFDPs at baseline (MonoZR: n = 28; PFM: n = 27), and 45 completed the 3-year follow-up. Two prosthesis failures occurred, one in each group, both associated with implant loss, with no difference in survival between groups (p = 1.00). Veneering ceramic chipping occurred only in the PFM group (3/23; 13%) and not in the MonoZR group (0/22) (p = 0.11). Complication-free survival, peri-implant clinical parameters, and MBL changes did not differ significantly between groups (p > 0.05). Plaque index and bleeding on probing increased over time, while probing depth and MBL remained stable. Both groups showed high clinical acceptability according to USPHS criteria. CONCLUSIONS: Both MonoZR and PFM posterior three-unit iFDPs demonstrated high survival and favorable biological outcomes after 3 years. MonoZR showed no chipping events and may represent a promising alternative to PFM for posterior implant-supported restorations. TRIAL REGISTRATION: German Clinical Trials Register: DRKS00011039.