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Aim: The current study sought to assess the impact of various surface treatments on microtensile bond strength (TBS) and colour stability in hybrid ceramic mended with composite.
​Materials and Methods: Fifty specimens were prepared from available nano ceramic hybrid CAD /CAM blocks then divided into : Group I, micro bars shaped specimens for micro tensile bond strength testing and group II, slices shaped specimens for color stability testing .Then specimens from each group were divided to five sub-groups according to the surface treatment used diamond abrasion(D), diamond abrasion and silane coupling agent(DS), sandblasting(B), sandblasting and silane (BS), and silane coupling agent (S).Dual cure resin cement was applied to the specimens , then composite was built up and photoactivated to form ceramic-composite complex .The microbars was subjected to microtensile bond strength test using universal testing machine .Reflective spectrophtometer was used to determine the color of the ceramic-composite slices specimens in CIELAB system.
​ Results: The highest color change was seen in the silane subgroup (S), while the diamond abrasion subgroup (D) showed the lowest color change followed by diamond abrasion and silane subgroup (DS). sandblasting and silane (BS) showed the highest µTBS values followed by diamond and silane (DS). The lowest µTBS was seen in the silane (S) subgroup.
​Conclusion: Different surface treatments increased microtensile bond strength and had an effect on color stability of hybrid ceramic repaired with composite.M