Influence of ceramic thickness on biomechanical behavior, survival and translucency of monolithic crowns

Abstract

This study aims to evaluate the biomechanical behavior, the fatigue strength and the translucency of monolithic crowns in different thicknesses. For this, total crowns will be made for element 26 in different ceramics: YZHT - high translucency zirconia partially stabilized by yttria (Vita YZ-HT), ZLS - lithium silicate reinforced by zirconium (Vita Suprinity) and PIC - hybrid ceramic Vita Enamic), (all, Vita Zahnfabrick, Bad Sackingen, Germany). Initially, a nonlinear analysis using finite elements will be performed to measure the stress distribution across the structures. For in vitro analysis, 63 conservative preparations for total crown will be machined in epoxy resin that will receive monolithic crowns with minimum thickness (MT) of 0.5 mm and 63 conventional preparations, crowns with MT of 1 mm. Two standard preparations will be scanned and monolithic crowns will be virtually drawn on them, which will be milled and sintered / crystallized according to the manufacturer's recommendations and then allocated into 6 groups (n = 21, N = 126). The crowns will be cemented to the preparations and then three specimens from each group will be submitted to the monotonic compression test, the others will be submitted to the Step stress fatigue test. The failure module will be evaluated by stereomicroscope and scanning electron microscopy. The translucency of the materials in each MT will be evaluated using the transmittance technique. The results will be analyzed statistically and discussed in the literature. (AU)