1. Prospective clinical evaluation of chairside-fabricated zirconia-reinforced lithium silicate ceramic partial crowns—5-year results
- Author
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Dirk Ziebolz, Andreas Leha, Tim Hausdörfer, Torsten Wassmann, Tanja Zuck, and Sven Rinke
- Subjects
Molar ,Ceramics ,Dentistry ,Lithium ,Clinical study ,CEREC ,Materials Testing ,Premolar ,Humans ,Medicine ,Bicuspid ,Dental Restoration Failure ,Prospective Studies ,General Dentistry ,Survival rate ,Crowns ,Proportional hazards model ,business.industry ,Silicates ,Hazard ratio ,Dental Porcelain ,Confidence interval ,medicine.anatomical_structure ,Dental Prosthesis Design ,Computer-Aided Design ,Zirconium ,business - Abstract
Objectives A university-based randomized clinical study evaluated the 5-year performance of chairside-fabricated zirconia-reinforced lithium silicate (ZLS)-ceramic partial crowns. Material and methods Forty-five patients were restored with 61 chairside-fabricated ZLS-restorations (Cerec SW 4.2, Dentsply Sirona, Germany; Vita Suprinity, Vita Zahnfabrik, Germany). Deviating from the manufacturers’ recommendations, restorations with reduced minimum material thicknesses (MMT) were fabricated: group 1, MMT = 0.5–0.74 mm (n = 31); group 2, MMT = 0.75–1.0 mm (n = 30). For luting, a self-adhesive cement (SAC) or a total-etch technique with a composite cement (TEC) was applied. Statistical evaluation was performed by time-to-event analysis (Kaplan–Meier). Possible covariates of the survival (SVR) and success rates (SCR), evaluated in a Cox regression model, were MMT, restoration position (premolar/molar), and cementation technique (SAC vs. TEC). Results Forty patients (54 restorations, premolars, n = 23; molars, n = 31) participated in the 5-year follow-up. Five losses due to ceramic fractures occurred in group 1 (n = 28) (SVR: 83.0% [95% confidence interval (CI): 0.71–0.96]). Group 2 (n = 26) showed no losses (SVR: 100%). The success rate for partial crowns placed on premolars was 100% and 69% (95% CI: 0.54–0.84) for molar restorations. Recementation was required in 4 restorations with SAC (SCR: 86% [95% CI: 0.73–0.99]; SCR-DC: 100%). Restorations in group 2 showed a significantly reduced risk of material fracture hazard ratio (HR) = 0.09, p = 0.0292) compared with the restorations in group 1. Molar partial crowns showed an increased risk for a clinical intervention (HR = 5.26, p = 0.0222) compared to premolar restorations. Conclusions Material thickness and position of the restoration are risk factors influencing the survival and success rate of ZLS-ceramic partial crowns. Clinical relevance Observation of an MMT of at least 0.75–1.0 mm for ZLS-ceramics is essential to avoid material-related fractures. Clinical trial registration: German Clinical Trails Register (trial number: DRKS00005611)
- Published
- 2021