Orthodontic bracket bonding with a plasma-arc light and resin-reinforced glass ionomer cement

Developments in light-curing technology have led to the introduction of a p lasma-are light-curing unit that delivers high-intensity output for faster curing. The purposes of this study were to determine the shear bond strengt hs of light-cured resin-reinforced glass ionomer cement cured with a plasma -are light-curing unit and to evaluate the durability of the resultant bond strength with thermal cycling. Comparisons were made between light-cured r esin-reinforced glass ionomer cement and light-cured composite resin. Two l ight-curing units were used in this study: a plasma-are light-curing unit a nd a conventional light-curing unit. The mean shear bond strengths of light -cured resin-reinforced glass ionomer cement with the plasma-are and the co nventional light-curing units were 20.3 MPa and 26.0 MPa, respectively. An analysis of variance showed no statistically significant differences betwee n the plasma-are and the conventional light-curing units. Light-cured resin -reinforced glass ionomer cement and light-cured composite resin demonstrat ed similar bond strengths and exhibited no statistical differences. There w as no statistical difference in bond strength between the teeth that were t hermal cycled and those that were not. Failure sites for the brackets bonde d with light-cured resin-reinforced glass ionomer cement appeared to be pre dominantly at the bracket-adhesive interface. The SDs of light-cured compos ite resin were high for both light-curing units. Whereas the coefficients o f variation for light-cured resin-reinforced glass ionomer cement ranged fr om 20% to 30%, those of light-cured composite resin ranged from 40% to 60%. The bond strength of light-cured resin-reinforced glass ionomer cement cur ed with either a conventional light-curing unit or a plasma-are light-curin g unit surpassed the clinically required threshold. The plasma-are light-cu ring unit may be an advantageous alternative to the conventional light-curi ng unit for orthodontic bracket bonding with both light-cured resin-reinfor ced glass ionomer cement and light-cured composite resin.