to occur, tensile stresses must first overcome this residual compressive stress. Since typical mastication stresses do not exceed 40 MPa, the ITD prevents cracks from forming during normal daily use and helps deflect cracks perpendicular to the dentin tubule and away from the pulp.

Inelastic deformation of dentin primarily happens through microcracking. Crack propagation within dentin travels preferentially along the interfaces of the ITD layers. Since the PTD, the hydroxyapatite tablets are