抄録
The enamel is considerably hard and brittle in the human tissues. Fracture toughness K_<IC> is used to evaluate brittle materials. In addition, K_<IC> reflects the resistibility of a material to crack initiation and unstable propagation. In this study, we investigated fracture toughness and Vickers hardness number through an indentation microfracture method with a Vickers microhardness testing machine.
