Deciphering dentin tissue biomechanics using digital moiré interferometry: A narrative review

The functional integrity of human teeth to different thermo-mechanical stresses relies on the characteristics of dentin. Dentin is a biocomposite and biologically adapted material that is composed of mineral, organic and water phases. It displays conspicuous gradients in its ultrastructural, physical and mechanical characteristics, which experiences further variations with age and disease. Thus the biomechanical behavior of tooth/dental hard tissues under different functions is considered extremely complex. Photomechanical techniques utilize optical principles to study the biomechanical response of biological tissues under functional forces. They are largely non-destructive techniques, which provide high-sensitive, and whole-field information of specimens in situ. They have been applied extensively in dentistry to understand the biomechanical principles underlying the responses of dental hard tissue, tooth-bone relationship and restorative appliances to different forces generated within the mouth. In this line, moiré interferometry is an established method to study the deformation patterns in tooth and dental hard tissues under water-loss/thermo-mechanical loads. This article aims to provide a comprehensive review on the application of moiré interferometry to understand the biomechanical response of teeth/dentin hard tissue.