BOND STRENGTHS AND REMNANT ADHESIVES RESIN ON DEBONDING FOR ORTHODONTIC BONDING TECHNIQUES

Bond strengths and remnant adhesive resin on the tooth surface after d ebonding for three bonding techniques used to attach foil mesh orthodo ntic brackets to 315 freshly extracted bovine incisor teeth were compa red in an in vitro study. Each method of bonding used 105 teeth in gro ups of 15, bonded with seven different (bis-GMA type) two-paste chemic ally cured resins. The direct method comprised bonding the attachments directly to the incisors with the composite resin. The indirect-1 met hod comprised securing attachments to die-stone models of the teeth wi th a water soluble glue, making silicone positioners to transfer the b rackets from the models to the teeth, and bonding to the teeth with th e use of the two-paste composite resin system. The indirect-2 method c omprised 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 o f unfilled sealant resin. Significant differences in bond strength exi sted among the groups evaluated. The direct technique had statisticall y significant (p < 0.05) higher bond strength as compared with the ind irect-1 and indirect-2 techniques in four of the seven groups evaluate d. The indirect-1 and indirect-2 techniques were not significantly dif ferent (p < 0.05) in bond strength in six of seven groups tested. The indirect-2 technique had significantly lower adhesive remnant index sc ores (ARI) compared with the direct and indirect-1 techniques. The dir ect technique had significantly lower adhesive remnant indices compare d with the indirect-1 technique. Thus the indirect-2 technique of bond ing orthodontic brackets to teeth demonstrated comparable laboratory b ond strengths and easier clean-up during the debonding procedure.