In vitro bond strength of treated direct-bonding metal bases.

Three types of direct-bonding metal bases were used to determine the effect of five commercial surface treatments on in vitro tensile bond strength. The proprietary treatments were etching, silanation, surface activation, etching plus silanation, and etching plus surface activation. Nontreatment was used as a control. The bases were of the mesh, photo-etched, and grooved types. Bases were loaded with a no-mix adhesive to plastic substrates. The grooved base had the highest bond strength with no treatment. Etching improved the bond strength of the grooved bracket by 56%. Silanation improved the bond strength of the mesh bracket by 28%. Surface treatments did not improve the bond strength of the photo-etched bracket.