Damage Accumulation Simulations in the Adhesive of Enamel/Ceramic Interface Using the FE Submodelling and the Element Deactivation Approaches

Purpose: To investigate the micromechanics and damage accumulation of the enamel/adhesive interface using submodelling and element deactivation methods. Materials and Methods: A finite element (FE) macromodel of the enamel/adhesive/ceramic interface subjected to shear bond testing was generated for mechanical analysis. The FE micromodel was constructed at the upper enamel/adhesive interface where stress concentration was found. The morphology of the micromechanical interlockings at the bonded interface was assigned based on a scanning electron micrograph. Boundary conditions of the micromodel were determined from the macromodel's results. Furthermore, an iterative code with the element deactivation method was used to calculate the microdamage accumulation. Parallel experiments were performed to validate the simulation. Results: The micromodel results demonstrated that stress concentration within the adhesive mainly occurred at the upper corner near the enamel/adhesive interface and the base of the resin tags. A simulated fracture path was found at the base of the resin tags along the enamel/adhesive interface. The morphological observation of fracture patterns obtained from in vitro testing corresponded with the simulation results. Conclusion: This study showed that the FE submodelling and the element deactivation approaches could better simulate the micromechanical responses and the microdamage accumulation noted at the enamel/adhesive interface. Keywords: micromechanics, enamel bonding, interface, finite element analysis, damage accumulation