Posterior monolithic 3-unit zirconia fixed dental prostheses: one-year interim results of a multicenter randomized clinical trial

Objectives: To compare the survival rates and clinical outcomes of posterior 3-unit monolithic zirconia fixed dental prostheses (FDPs) to veneered zirconia FDPs. Methods: Sixty-four patients missing single teeth in the posterior mandible or maxilla were recruited. Patients’ restorations were randomly allocated to three groups: 1) monolithic zirconia FDPs (Mono-FDP, n = 21); 2) partially veneered zirconia FDPs (PV-FDP, n = 21); 3) circumferentially veneered zirconia FDPs (V-FDP, n = 22). Technical complications were evaluated by modified United States Public Health Service (USPHS) criteria at one-year follow-up appointments. Radiographs, clinical parameters including probing pocket depths (PD), bleeding on probing (BOP), plaque index (PI) and patient-reported outcome measures (PROMs) of prostheses and patients were evaluated at baseline and one-year follow-up appointments. The results were evaluated descriptively. Results: Sixty-two patients were available for re-examination, two patients in PV-FDP group were lost to follow-up. At one-year follow-up, no FDPs were lost. Technical complication rates, namely small fractures were 0 % in the mono-FDPs, 9.5 % (2) in PV-FDPs and 22.7 % (5) in V-FDPs. USPHS rating A for patient satisfaction (PROMs) was given to 85.7 % (18) of Mono-FDPs, 85.7 % (18) of PV-FDPs and 90.9 % (20) of V-FDPs revealing high patient satisfaction with FPDs in all the groups at one year. Conclusions: According to the one-year interim results of this clinical study of the posterior tooth-supported FDPs, monolithic zirconia FDPs seem to show no technical complications whereas the veneered zirconia FDPs exhibited veneering porcelain chippings. Survival and biologic outcomes were excellent in all the study groups. Clinical significance: The present one-year interim results show that veneered, partially veneered and monolithic FDPs can be used with good confidence, however, FDPs with veneering ceramic might exhibit ceramic chippings.