Prosthetic outcomes and clinical performance of CAD-CAM monolithic zirconia versus porcelain-fused-to-metal implant crowns in the molar region: 1-year results of a RCT

Objective: To investigate the clinical performance of monolithic zirconia implant crowns as compared to porcelain-fused-to-metal (PFM) implant crowns.

Materials and methods: Seventy-six healthy patients received reduced diameter implants in the molar region. Following random allocation, either a monolithic zirconia crown (Mono-ZrO₂ ) or a (PFM) was inserted. Crown and implant survival rates, modified USPHS criteria, clinical measurements, and interproximal marginal bone level (MBL) were assessed at crown delivery (baseline, BL) and at the 1-year follow-up (1y-FU). Data were analyzed descriptively. Fisher's exact test and Wilcoxon rank sum test were applied for statistical analysis. The level of statistical significance was set at p < .05.

Results: Thirty-nine Mono-ZrO₂ and 37 PFM crowns were delivered. At the 1y-FU, one crown in each group was lost due to loss of the implant. Technical complications occurred in the PFM group and were limited to four minor ceramic chippings resulting in a total technical complication rate of 11.1% (p = .024). Anatomical form and color match compared to the adjacent dentition were rated significantly inferior for the Mono-ZrO₂ crowns. Patient satisfaction was high in both groups at BL (34 Mono-ZrO₂ 34 PFM) and at 1y-FU (36 Mono-ZrO₂ 31 PFM). No significant differences between the groups were detected with respect to the change in MBL and to the soft tissue parameters.

Conclusions: Monolithic zirconia crowns are a similarly successful alternative option to PFM crowns for restoring single implants in the posterior area.