| Objective:To study three kinds of orthodontic adhesives clinical commonly used in metal brackets and ceramic brackets bonding strength in a dry and artificial saliva environment,and to evaluate its bonding properties and provide a reference for clinical application.Methods:120 premolars extracted for orthodontic reasons were randomized into 12 groups(A1, A2, A3, A4, B1, B2, B3, B4, C1,C2,C3 and C4). Group A was assigned for 3M light curing adhesive. A1 Group: dry condition + metal brackets + 3M light curing adhesive, A2 group: artificial saliva condition + metal brackets + 3M light curing adhesive, A3 Group: dry condition +ceramic brackets + 3M light curing adhesive,A4 group: artificial saliva condition + ceramic brackets + 3M light curing adhesive.Group B was assigned for 3M chemical curing adhesive. B1 group:dry condition + metal brackets + 3M chemical curing adhesive,B2group: artificial saliva condition + metal brackets + 3M chemical curing adhesive,B3 group: dry condition + ceramic brackets + 3Mlight curing adhesive, B4 group: artificial saliva condition + ceramic brackets + 3M chemical curing adhesive. Group C was assigned for Hangzhou West Lake enamel adhesive. C1 group: dry condition +metal brackets + Hangzhou West Lake enamel adhesive,C2 group:artificial saliva condition + metal brackets + Hangzhou West Lake enamel adhesive,C3 group: dry condition + ceramic brackets +Hangzhou West Lake enamel adhesive,C4 group: artificial saliva condition + ceramic brackets + Hangzhou West Lake enamel adhesive. An electronic universal mechanical testing machine was employed to characterize the bonding strength of adhesives of each group in dry or artificial saliva environment. A microscope was to observe the adhesive remnant on the tooth surface. Scanning electron microscope was utilized to observe morphologies of tooth surface detached from metal brackets.Results:In dry environment, bonding strength of all adhesives was significantly different from each other(P <0.05).In artificial saliva environment,bonding strength of three kinds of adhesives with metal brackets and ceramic brackets was significantly different from each other(P <0.05).In the same environment,same kind of adhesive with metal brackets and ceramic brackets was not significantly different fromeach other(P <0.05).Under different conditions,metal brackets with 3M chemical curing adhesive bond strength was statistically significant under different conditions(P <0.05),with the other two kinds of adhesive bond strength was not statistically significant(P> 0.05).Under different conditions,bonding strength of three kinds of adhesives with ceramic brackets was significantly different from each other(P<0.05).Under different conditions,after the removal of metal brackets,adhesive remnant index(ARI) was statistically significant(P <0.05).Under different conditions,after the removal of ceramic brackets,adhesive remnant index(ARI) was not statistically significant(P >0.05).Tooth surface after adhesive bonding demonstrates inordinately changes. In the group of 3M chemical curing adhesive, enamel surface shows irregular embossment while for that of 3M light curing, ordered and flat surface was revealed. In the group of Hangzhou West Lake, cracks were present along with irregular embossment.Conclusion:1. In both dry and artificial saliva environment,bond strength of three kinds of adhesives with metal brackets and ceramic bracketsfulfilled orthodontic clinical requirements, among which 3M light curing adhesive demonstrated the best potential.2. Under the same experimental conditions, bonding strength of metal brackets and ceramic brackets didn’t present significant difference.3. 3M light curing adhesive had the lowest ARI in both dry and artificial saliva environment.4. After the complete removal of the adhesive from tooth surface,damage was found to be least severe in the group of 3M light curing,showing ordered and flat surface. |
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