Retrospective, Multicenter Cohort Study Evaluating Clinical, Technical, Biologic, and Esthetic Outcomes of Implant- Supported Zirconia Single Crowns Cemented on Titanium- Base Abutments: 7-Year Mean Follow-Up.

PURPOSE: To retrospectively evaluate the long-term clinical, technical, biologic, and esthetic outcomes of implant-supported single zirconia crowns (ISCs) intraorally cemented to titanium-base (Ti-base) hybrid abutments up to 16 years after placement. MATERIALS AND METHODS: A total of 63 ISCs were evaluated in 36 patients at two different private practices.Original Ti-bases were selected, and zirconia (Zr) mesostructures and Zr crowns were designed using CAD/CAM software and then milled from partially stabilized Zr blocks. After the mesostructures were cemented extraorally onto the Ti-bases, the Zr crowns were intraorally luted to the hybrid abutments. The Ti-base ISC restorations were followed for up to 16 years, and their clinical, biologic, and esthetic outcomes were recorded at distinct time points at 3-year intervals: October 2019 (T1) and October 2022 (T2). RESULTS: A total of 36 patients (18 men, 18 women) received 32 ISCs in the anterior region and 31 ISCs in the posterior region of the maxilla and mandible. The mean follow-up of the Ti-base ISCs was 6.93 +/- 2.60 years. The mean follow-up of the implants amounted to 8.11 +/- 3.26 years. No implants were lost during follow-up, resulting in a cumulative implant survival rate of 100%. Abutment screw loosening was observed in two ISCs after 1 year of function. The overall cumulative restorative survival rate of the Ti-base restorations was 96.83%. At the T2 follow up, 24% of the ISCs exhibited an increase in probing depth (PD) despite maintaining clinically healthy peri-implant tissue. An 11% increase in bleeding on probing (BoP) and a 3.17% decrease in the plaque index (PI) were recorded. Despite spectrophotometrically measured DeltaE values indicating visible discoloration of some restorations and their peri-implant soft tissue, a low incidence of esthetic complications was observed with an average pink and white esthetic score (PES/WES) of >/= 12. No correlation was found between PES (R = -0.25; P = .27) and WES (R = -0.18; P = .43) scores and digital shade determination. CONCLUSIONS: The results indicate satisfactory clinical outcomes for intraorally cemented ISCs supported by Ti-base hybrid abutments. An overall esthetic superiority of Ti-base ISCs could not be confirmed.