Abstract
The main objectives of this study were to determine the effect of different nickel - chromium alloys with different surface treatment bonded to enamel tooth surface on the shear bond strength. Seventy five wax disc-shaped samples were prepared. These discs were divided into three groups, (25) in each. The first group was casted with CB-Bland 72 alloy, the second with CB-soft alloy, and the third group with Kera - N alloy. For surface treatment procedures each group was divided into five subgroups, five samples in each: the first subgroup was sandblasted with (50) μm Al2O3 plus electrolytical etching. The second subgroup only electrolytically etched; the third subgroup sandblasted with (50) μmAl2O3. The fourth subgroup sandblasted with (100) μm Al2O3, and the fifth subgroup received no surface treatment. The metal discs were bonded to the labial surface of upper central and lateral incisors using intermediate resin and adhesive luting cement. The samples were thermocycled between (5-60) C°± (2) C° for (500) cycles at (1) minute dwell time and then stored in distilled water in an incubation at (37) C° for seven days. After that the shear - bond strength were tested.
The results showed that the mean shear-bond strength of CB-Bland 72 alloy was found to be greater than that of Kera - N and CB-Soft alloys, and surface treatment with (100) μmAl2O3 procedure exhibit the highest bond strength.
