Abstract

Introduction:
(CAD/CAM) ceramic restorations has been widely used in the field of fixed prosthodontic dentistry. . CAD/CAM ceramics blocks were reported of having less internal porosity, hence the fracture failure occur at a lower rate than conventional layered ceramics. fracture does not frequently result in restoration failure, but it does cause aesthetic and masticatory problems for the patient. Restorations can be replaced or repaired in situations. Micromechanical and chemical methods of retention can be used to repair ceramic-composite surfaces in order to achieve a solid bond.
Materials and Methods:
70 specimens of two different materials were divided into groups :( Group A) Vita supernity and (Group B) Vita Enamic were used in this in vitro study. 35 specimens with (14x12x3) were made using a slow-speed cutting machine from each material.Each group will then be subdivided into five subgroups according to the surface treatment techniques into Subgroup (1):hydrofluoric acid, Subgroup 2 Er:YAG,Subgroup (3) Er,Cr:YSGG, Subgroup (4) EY+ air abrasion Subgroup 5 ECY+air abrasion.According to the manufacturer's recommendation, group B was subjected to crystallization.Each group (n=7) received a surface treatment,SEM were measured then silane coupling agent , bonding aget, composite were applied .lastly thermocycling then shear bond strength was measured.
Results:
measurements showed higher shear bond strength in Hf acid surface treatment showed in both Vita Suprnity and Vita Enamic
Conclusion:
Surface treatment affected the shear bond strength of Vita Suprnity and Vita Enamic .HF achieved the highest in Vita Suprnity and in Vita Enamic.
Keywords:
CAD/CAM blocks,Laser,Shear bond strength.