الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
This study was conducted to evaluate fracture resistance and marginal fit and failure mode of endocrown restorations fabricated by three different materials, lithium disilicate glass ceramic, full contour zirconia material, and resin nanoceramic. Eighteen endocrown restorations were fabricated and evaluated on lower molar teeth and was categorized into 3 groups n=6. group (I): LD: lithium disilicate, group (II): FCZ: full contoured zirconia, group (III): RNC: resin nanoceramic. Restorations were treated and cemented and according to manufacturer’s instruction. Specimens were aged by thermomechanical aging to simulate six months of clinical service. Marginal gaps were measured by stereomicroscope and fracture resistance were evaluated under universal testing machine then failure mode analysis was assessed. The results of current study showed that the type of material type and thermomechanical cycling have an effect oon the marginal gap. all marginal gap values were within the acceptable clinical parameters. Fracture resistance values were highest in zirconia, then lithium disilicate and least in resin nanoceramic group.