Combinations of etchants, composite resins, and bracket systems: An important choice in orthodontic bonding procedures

The objectives of this investigation were: (1) to compare the shear bond st rengths (SBS) of metal, ceramic, and plastic brackets using different conce ntrations of maleic and phosphoric acid gels and aqueous solutions, and (2) to determine if a relationship exists between the type of acid etchant and the location of resin after debonding. A sample of 210 bovine incisors was divided among three different bracket groups (Victory series metal, Transc end 6000 ceramic, Spirit MB plastic). Prior to bonding, enamel was acid-etc hed using 37% phosphoric acid (H3PO4) gel and aqueous solution, 10% maleic acid gel and aqueous solution, 10% H3PO4 gel and aqueous solution, or 2% H3 PO4 aqueous solution. SBS testing and the adhesive remnant index (ARI) scor e provided insight into the effects of the bonding process on enamel. Resin tags associated with each etchant type were inspected under scanning elect ron microscopy (SEM). Statistical analyses (level of significance, p=0.05) of the data showed significant differences among groups. It was concluded t hat specific acid-composite-bracket combinations are recommended for use in clinical orthodontic practice in order to achieve efficient bonding.