الفهرس 
Materials and MethodsOnly 14 pages are availabe for public view
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Abstract
This study evaluated the effect of different surface treatments of Ni-Cr alloy and porcelain on the shear bond strength of both direct and indirect repair techniques. In order to investigate this, a total number of 60 disks were prepared and divided according to the type of repair into; group A (40 disks) for the Direct technique and group B (20 metal disks) for the Indirect technique. Specimens of group A were subdivided into two subgroups; metal disks (subgroup Aa) and porcelain disks (subgroup Ab).
Metal disk samples were divided equally and randomly into four subgroups each consist of 5 disks according to surface treatment into: (1) Control (2) Metal primer (3) Sandblasting. (4) Sandblasting and metal primer. For each subgroup single bond adhesive was applied as a bonding agent before application of composite (for direct method) or resin cement (for indirect method). While porcelain disks samples (Subgroup Ab) were divided equally and randomly into four divisions each consist of 5 disks according to surface treatment into: (1) Control (2) Etching with 9.5% Hydrofluoric acid (3) Sandblasting. (4) Sandblasting and etching. For each division ceramic primer (silane) and single bond bonding agent were placed before application of composite resin. All samples were stored in distilled water at 37°C for one week. Shear bond strength was measured using universal testing machine.
The results of this study showed that : For the direct repair, the highest mean bond strength of composite bonded to ceramometallic alloy surface was accompanied with sandblasting( 17.3MPa) while the highest bond strength of composite to porcelain was scored with combined sandblasting+ HF acid etching of porcelain surfaces (19.4 Mpa). For the Indirect repair both sandblasting and metal primer application on metal surface resulted in the highest shear bond strength values (11.98MPa). The mean shear bond strength of all direct repair metal specimens was higher than those of the indirect repair.