Shear strength of ceramic brackets bonded to porcelain.

The purpose of this study was to compare the bond strengths of three different adhesive systems when used alone and combined with a porcelain priming agent to bond ceramic brackets to porcelain surfaces. Sixty porcelain specimens were randomly assigned to the six different treatment groups. Half were bonded with the porcelain priming agent and one of the adhesive systems and the other half with one of the adhesive systems alone. The shear bond strengths of all specimens were tested, with an Instron testing machine, 10 minutes after being bonded. The surface of the porcelain and the bracket base were examined, with scanning electron microscopy (SEM) and qualitative energy dispersive x-ray analysis (EDS), to determine the bond failure patterns and to check the porcelain surface for the presence of cracks and fractures. There was a statistically significant difference within each adhesive between those samples with the priming agent and those without the priming agent. Differences between the three adhesives were not statistically significant (p < or = 0.05).