الفهرس 
Evaluation of fracture resistance and vertical marginal gap of hybrid versus pressable ceramic laminate veneers
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Abstract
In the 21st century of cosmetic dentistry, porcelain laminate veneers have been increasingly used for the esthetic restoration of anterior teeth and at the same time provide sound and long-lasting esthetic results. The purpose of this study was to compare hybrid ceramic veneers and pressable laminate veneers regarding resistance to fracture and vertical marginal discrepancy of both materials following thermal cycling. A total of twenty four of comparable human central maxillary incisors were extracted for periodontal reason, were selected for the present study. In order to standardize the preparation to receive laminate veneer restoration, the teeth were prepared by computer numerically controlled CNC milling machine to be copied out of laminate veneer preparation. The samples were divided into two main groups [I &II] according to the material used for construction of laminate veneers restoration: I. Twelve teeth received Vita Enamic hybrid ceramic laminate veneers. II. Twelve teeth received IPS E.max Press ceramic laminate veneers. The Vita Enamic hybrid ceramic laminate veneers were fabricated from Vita Enamic blocks milled by a Cerec in-Lab CAD/CAM Machine. While the IPS E.max Press ceramic laminate veneers were fabricated from machinable CAD/CAM wax discs (CAD wax) to have equal and standardized thickness of all samples. This wax was milled by Laserdenta CAD/CAM system, then invested, casted, and the ceramic was pressed, divested, and finally glazed. All laminate veneers restorations were finished according to the manufacturer instructions. Then, each restoration was surface treated with hydrofluoric acid and silanated. The prepared surface of all teeth specimens was also treated by acid etch and bonding agent, then each laminate veneer restoration was luted to its corresponding prepared tooth with A light cure composite resin luting agent (RelyX Veneer 3M ESPE). All samples were subjected to thermocycling between 5C{u00B0} to 55C{u00BA} in water bath for a total of 1750 cycle with 10 seconds dwell time at each bath using thermocycling device