Abstract
Objective
This in vitro study aims to evaluate load‐to‐failure of ceramic veneers with butt joint (BJ) and feathered edge (FE) incisal preparation designs, and to correlate these results to the failure mode of the restorations.
Materials and methods
One hundred and forty‐eight typodont teeth (customized Nissin A25A‐UL19B) were divided into two different preparation configurations BJ and FE and two different loading angulations, 0° and 20°. Lithium disilicate ceramic veneers (IPS e.max CAD, Ivoclar Vivadent) were milled using computer‐aided‐design‐and‐computer‐aided‐manufacturing (CAD/CAM) techniques. Veneers were bonded to typodont teeth with resin cement (IPS Variolink Esthetic, Ivoclar Vivadent). Each group was loaded at the incisal edge using an Instron Universal Testing Machine at a crosshead speed of 0.01 mm/s till failure.
Results
Pairwise comparison showed veneers from the BJ groups had a significantly higher load‐to‐failure value compared to the FE groups. Veneers with a FE preparation design loaded at 20° angulation had the lowest load‐to‐failure value.
Conclusions
Within the limitations of the present study, both incisal preparation designs and loading angulations have significant effects on the load‐to‐failure values of ceramic veneers. BJ group exhibits a significantly higher load‐to‐failure value compared to the FE group.
Clinical significance
BJ incisal preparation is preferred over FE preparation design.