Multicenter Prospective Clinical Study on Chairside‐Fabricated Partial Crowns: 5‐Year Results for Lithia‐Zirconia Glass–Ceramic Restorations

Abstract

ABSTRACT Objectives Clinical evaluation of chairside‐fabricated lithia‐zirconia glass–ceramic (LZGC) partial crowns (CCPCs) in a multicenter practice‐based study. Materials and Methods Seventy‐one patients were restored with 92 adhesively luted CCPCs (Cerec SW 4.2/Cerec MC XL/Celtra Duo) in three private dental clinics (C1–C3). Time‐dependent (Kaplan–Meier) survival rates (SVR) and success rates (SCR) were calculated. The following possible covariates of SVRs and SCRs were evaluated in a Cox regression model: Restoration position (premolar/molar), luting material (Variolink/Calibra), and operator (C1–C3). Results Seventy‐three CCPCs were placed in 59 patients and were included in the study (mean observational period: 58.0 ± 15 months). Four complete failures (two tooth fractures, one restoration fracture, and one endodontic failure) were recorded. All failures and interventions occurred in one of the three centers (5‐year SCR: C1 + C2: 100%; C3: 71%; 95% confidence interval: [0.55; 0.87]). Additionally, three biological, and two technical complications required clinical intervention to maintain function, and all occurred in C3. Restorations placed in C1 and C2 showed a significantly reduced risk for failure/intervention (hazard ratio = 0.103, p = 0.026) compared with restorations placed in C3. Conclusions LZGC CCPCs showed good five‐year clinical performance. However, SVRs and SCRs were significantly influenced by the operator. Additional clinical data are required for a more detailed investigation of this effect.