Application of Diametral Compression Test to Evaluation of Dentin-Adhesive Interface Bond Strength

Abstract

Bond strength test is crucial for evaluation of dentin-adhesive effectiveness and for informing the design of adhesive systems. Conventional bond strength techniques have limitations with respect to accuracy and suffer from large variability. Diametral compression test is an alternative approach for evaluating bond strength which aims to simplify the boundary conditions during loading. For the dentin-adhesive interface, this type of test can be applied to not only access the tensile behavior but also behavior under complex combined normal and shear loading conditions. With an aim to design laboratory experiments, extensive finite element analyses are carried out on diametral compression test. The performed analyses utilize a novel granular micromechanics based user-defined nonlinear material model that has been implemented into commercial finite element analysis software. Failure evolution and debonding are investigated for FE models with varying geometries, materials and interface properties. Results of this numerical study shows that failure mode can be controlled by changing the design of diametral compression disc samples and accordingly, accuracy of bond strength test can be improved. Furthermore, diametral compression test can provide tensile and shear bond strength test using a single test setup changing interface orientation of a bilayered disc specimen.