Clinical Evaluation of Chairside-Fabricated Partial Crowns Made of Zirconia- Reinforced Lithium Silicate Ceramic - 2-Year-Results.

Abstract

In a prospective study, the clinical performance of chairside-fabricated partial-crowns made of zirconia-reinforced lithiumsilicate (ZLS)-ceramic was evaluated after 2 years. 45 patients (28 female/17 male) underwent restoration with 61 chairside-fabricated ZLS partial-crowns on vital premolars and molars. In variation from the manufacturer's recommendations (minimum material thickness (MMT)=1.0 mm), partial-crowns with reduced material thicknesses were fabricated: group 1, MMT=0.5-0.74 mm (n=31); group 2, MMT=0.75-1.0 mm (n=30). The restorations were luted with either a self-adhesive cement (SAC) or the total-etch technique using a dual-curing composite cement (DC). The MMT and cementation technique (SAC vs. DC) were evaluated as possible covariates of the time-dependent survival (SVR) and success rate (SCR) using univariate log-rank-tests. Forty-four patients with 59 restorations participated in the 2-year follow-up examinations. In group 1 (n=31), there were 2 losses due to ceramic fracture (SVR: 94.0% (95% confidence interval (CI): 0.85-1)). In group 2, no losses were documented (SVR: 100%). In 2 restorations cemented with SAC, recementation was necessary (overall SCR: 93% (CI: 0.87-1)). To avoid early material-related fractures, observing the recommended minimum thickness of 1.0 mm is essential. However, further validation of these results in studies with longer observational periods is required.