Abstract
Cylindrical human enamel specimens were examined by the direct tensile test using the pinvise chuck built as a trial and the diametral test for indirct tensile strength. Tensile strengths were compared with the previously reported data on compressive strength of human enamel. The tensile strength, both direct and indirect, differed markedly according to the direction of enamel rods. The mean direct tensile strength was 21.9MPa in the direction of enamel rods axes V, 13.9MPa in the direction of crosss sectional longer axes of rods I, and 10.4MPa in the direction of H perpendicular to the directions of V and I. The mean diametral compressive strength was 45.6MPa in the direction of V, 37.7MPa in the direction of I, and 25.5MPa in the direction of H. The chucks to grip the test pieces were manufactured for trial and they were useful for the direct tensile test of enamel.
