Bond strengths and remnant adhesive resin on debonding for orthodontic bonding techniques

Bond strengths and remnant adhesive resin on the tooth surface after debonding for three bonding techniques used to attach foil mesh orthodontic brackets to 315 freshly extracted bovine incisor teeth were compared in an in vitro study. Each method of bonding used 105 teeth in groups of 15, bonded with seven different (bis-GMA type) two-paste chemically cured resins. The direct method comprised bonding the attachments directly to the incisors with the composite resin. The indirect-1 method comprised securing attachments to die-stone models of the teeth with a water soluble glue, making silicone positioners to transfer the brackets from the models to the teeth, and bonding to the teeth with the use of the two-paste composite resin system. The indirect-2 method comprised bonding the attachments to die-stone models of the teeth with composite resin, making silicone positioners to transfer the brackets from the models to the teeth, and bonding to the teeth with the use of unfilled sealant resin. Significant differences in bond strength existed among the groups evaluated. The direct technique had statistically significant (p < 0.05) higher bond strength as compared with the indirect-1 and indirect-2 techniques in four of the seven groups evaluated. The indirect-1 and indirect-2 techniques were not significantly different (p < 0.05) in bond strength in six of seven groups tested. The indirect-2 technique had significantly lower adhesive remnant index scores (ARI) compared with the direct and indirect-1 techniques.(ABSTRACT TRUNCATED AT 250 WORDS)