The dental gold alloy shows a lower bond strength than the natural teeth in bracket bonding, and this can be a possible source of subsequent bond failure. This study aims to evaluate the effect of various gold alloy surface treatment techniques on shear bond strength between the orthodontic adhesives and the gold alloy and to find ways of increasing the bond strength. Two hundred and forty specimens made of the dental gold alloy were
divided into twelve groups based on the combination of surface treatment methods(non-surface treatment, sandblasted, sandblasted plus tin-plated, and sandblasted plus intermediate adhesive) and adhesive systems (Ortho-one, Panavia 21, Superbond C&B). The specimens with bonded brackets were placed in distilled water at 371C for 24 hours and shear bond strength was measured by a universal testing machine.
The results were as follows:
1. All surface-treated groups showed a significantly higher shear bond strength than non-surface-treated groups. 2. The sandblasted plus tin-plated grout showed a significantly higher shear bond strength than the sandblasted group only when Panavia 21 was involved.
3. The sandblasted plus intermediate adhesive group showed a significantly higher shear bond strength than sandblasted group regardless of the type of adhesive used.
4. Of.the three resin adhesive types, the Superbond C&B showed the highest bond strength, followed by Panavia 21 and Ortho-one.
These findings suggest that a combination of sandblasting and intermediate resin treatment is desirable in order to enhance bracket bond strength regardless of adhesive types.
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