الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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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 CERASMART and IPS e.max laminate veneers regarding resistance to fracture of both materials following thermal cycling with two different preparation designs (feather-edge and wrap-around).
A total of fifty two 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 groups [I & II] according to the material used for construction of laminate veneers restoration and each group subdivided into two groups according to type of preparation designs (feather-edge and wrap-around ) :
I. Twenty six teeth received CERASMART hybrid ceramic laminate veneers.
A:Thirteen without incisal reduction (feather-edge design)
B:Thirteen with incisal reduction (wrap-around design)
II. Twenty six teeth received IPS e.max Press ceramic laminate veneers.
A:Thirteen without incisal reduction (feather-edge design)
B:Thirteen with incisal reduction (wrap-around design) The CERASMART hybrid ceramic laminate veneers were fabricated from CERASMART blocks milled by a Cerec 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 5Cº to 55Cº in water bath for a total of 1750 cycle with 10 seconds dwell time at each bath using thermocycling device. After that all samples were subjected to the fracture resistance testing, the fracture load strength test was performed using the Universal Testing Machine. The results were calculated, tabulated and statistically analyzed
It was found that IPS e.max feather-edge group recorded fracture resistance mean value of (289.6N), IPS e.max wrap-around group recorded fracture resistance mean value of (422.1N), CERASMART wrap-around group recorded fracture resistance mean value of (317.23N) and CERASMART feather-edge group recorded fracture resistance mean value of (259.3N).