Dental restorative composite materials are recognized as an effective remedy to revive the function and integrity of deficient tooth structure. During their service life, dental restorative materials undergo different mixtures of tensile and shear loads accompanied by temperature changes, which in hand with preexisting voids and defective interfaces can lead to crack initiation and growth. In this paper, the fracture initiation is investigated under combined tension-shear loading for a dental biomaterial using a strain-based fracture criterion. In order to validate the fracture model, the experimental data reported in literature from fracture tests on a dental biomaterial, namely 75Sr10 are used. Fracture curves are then extracted using the strain-based fracture model for different combinations of tension and shear loading. It is shown that there is good agreement between the experimental data reported for the dental biomaterial and the theoretical results predicted by the strain-based fracture model.