The Bond Strength of Orthodontic Resins to Porcelain

Orthodontic brackets were bonded to one of two porcelain surfaces using a self-cured or one of two light-activated orthodontic bonding resins. The porcelain surfaces were either glazed (control) or de-glazed (experimental) by being subjected to either 1.23% APF for 4 minutes or roughened with a Busch silent wheel. The bonds were tested to failure in shear mode on a universal mechanical testing machine. For one porcelain, there was no significant difference in the mean bond strengths between the control and the APF-treated surface, but for the second porcelain the mean bond strength was significantly greater when the surface was de-glazed by abrasion. It is considered that the mean bond strengths may be inadequate to withstand manipulations associated with routine orthodontic therapy.