Stress analysis of first permanent mandibular molar with class 1 restorations of different cement bases by occlusive load: A finite element analysis

It was the aim of the study to analyze stress distribution in tooth and restoration by occlusal load of Class I. Comparative analysis was used to evaluate effects of four kinds of cement bases on the stresses in resin composite restorations. The elastic moduli and Poisson's ratios of the three kinds of restorative materials were tested. Micro-CT was used to scan the first mandibular molar, and the three-dimensional finite element model of the tooth with class I cavity was built by ABAQUS. Occlusive load of 250N was applied on the model. Then von Mises stresses distribution in the enamel, dentin, resin composite and bases were analyzed by occlusive loading of different cement bases. As single-layer base, the maximum von Mises stresses of the enamel and the dentin of the Dycal base were much lower than those of the VIT base. As double-layer base, the maximum von Mises stresses of the enamel and the dentin of VIT and Dycal were much higher than those of VIT and Ultra-blend plus. Cement bases should have a high elastic modulus in order to reduce the stress of the enamel and the dentin. The present study would help clinicians to make an informed choice of the cement bases to avoid the fracture of tooth or restoration.