Shear bond strength of ceramic brackets to resin-composite surfaces.

In this study, two types of ceramic brackets--monocrystalline and polycrystalline--were bonded to unroughened and roughened resin-composite discs using a light-cured orthodontic adhesive, and the bonds tested under shear stress in a universal testing machine. There was no significant difference in the shear bond strength between the combinations of ceramic brackets, and between the surface treatments of the resin composite. A higher frequency of resin-composite fracture was observed with the polycrystalline brackets (12/20) than with the monocrystalline ceramic brackets (7/20). It is concluded that debonding any type of ceramic bracket from a resin-composite surface may cause damage to the resin composite itself.