Systematized bracket-enamel adhesion test

Abstract

Objective: Bracket-enamel adhesion studies should address the most important issues – systematic tests and comparable results. Therefore, the purpose of this study is to standardize the bracket-enamel adhesion test by controlling all variables systematically. Materials and methods: Fifty-six human enamel-bracket adhesions were tested by controlling significant factors including enamel surface, adhesive paste and bracket. The thermocycling was completed (15 sec, 2000 cycles, 5 and 55 degree Celsius). The shear test was exerted by Instron Universal machine (Model 5566, Instron Corp., UK). Moreover, the failure site characteristics were evaluated. The results were analysed using Weibull analysis. Results: The mean debonding stress and Weibull modulus were 9.47 MPa (S.D.=1.41) and 7.58, respectively. This result was compared to relevant study using t-test. The result suggested that bonds of bracket to human enamel were significantly lower than bond to bovine enamel (P<0.01) despite the similar research methodology. Additionally, the failure sites were analysed using Adhesive Remnant Index (ARI). Most brackets of this study showed the ARI of three. Conclusions: To summarize, the mean stress to break the bond was 9.47 MPa (S.D.=1.41). It could also be concluded that meaningful comparison should arise from systematic studies. However, among the similar research studies, the debonding stress of bracket to bovine enamel was higher than human premolar enamel.