FRACTURE RESISTANCE OF LITHIUM DISILICATE VONLAYS VERSUS CELTRA DUO VONLAYS RESTORING PREMOLARS (IN VITRO STUDY)

Abstract

The aim of the present study was to compare the fracture resistance of lithium disilicate vonlays versus celtra duo vonlays restoring premolars -Fracture resistance values will be measured on vonlays fabricated using a computer-aided design/computer-aided manufacturing (CAD/CAM) system after their adhesive cementation to epoxy dies. According to sample size calculation, a total of twenty restorations were constructed. The samples were divided into two equal groups, ten samples for each group according to the material type used: -Group (a): Ten vonlay samples (n=10) fabricated of lithium disilicate CAD/CAM blocks -Group (b): ten vonlays samples (n=10) fabricated of Celtra® Duo CAD/CAM blocks. Anatural tooth represent first maxillary premolar was prepared according to regular dimensions of all ceramic restorations preparation guidelines with an occlusal reduction of Occlusal box with 1/2 of the buccal-lingual distance and a depth of 2 mm ,2 mm occlusal reduction of the functional cuspid with the preparation extended 2 mm in the cervical direction at the lingual surface.The preparation design for a complete veneer restoration will additionally extended to the labial surface with a chamfer reduction of 0.5 mm. All of the line angles will be rounded, and all of the margins will be finished. Preparation was performed manually and checked and confirmed by the main supervisior. The prepared natural tooth was then duplicated into twenty epoxy resin dies using silicon impression material.