Effect of resin cure mode and fluoride content on bracket debonding

Enamel decalcification around brackets is sometimes observed during and aft er orthodontic treatment. Reports in the literature suggest that the preven tive advantage of fluoride-releasing adhesive resins may be compromised by an increased incidence of bond failure. The purpose of this study was to de termine the effects on shear debonding of incorporating fluoride into the b racket bonding system. Another purpose was to determine the effect of polym erization mode on debonding. Orthodontic brackets were bonded to bovine ena mel using one of three types of adhesive resin-no-mix, chemically cured, or light-cured-each formulated with and without fluoride. The teeth were stor ed in artificial saliva for 24 hours or 30 days and then debonded in shear. Data analysis was performed using ANOVA followed by post-hoc multiple comp arison between group pairs. It was found that: (1) fluoride had either no e ffect or it increased the bond value; (2) the no-mix adhesive demonstrated the lowest bond value; (3) the duration of storage in artificial saliva had no effect on the bond value of the chemically cured and light-cured adhesi ves but did affect the no-mix adhesive; and (4) the no-mix adhesive release d significantly less fluoride than the two other products. Thus, the presen ce of fluoride in the bonding adhesive does not reduce the force required t o debond in shear, and chemically or light-cured adhesives provide consiste ntly higher bond values over extended immersion times than the no-mix produ ct.