Analysis of cyclic thermal stress on restored tooth using finite element analysis

Abstract

Introduction The intake of hot and cold substance in daily life generates cyclic thermal stress to tooth and this repeated stress may result in fatigue failure. The purpose of this study was to analyze the relationship between cyclic thermal stress and tooth crack formation using finite element analysis.

Methods A maxillary first molar with class I or class II restoration was modeled via CAD-FEM procedure. Thermal load based on in vivo experimental data was applied to class I/II prepared natural tooth without filling material (control) and class I/II gold restored tooth. Stress generated in tooth structure was examined. Predicted fatigue life based on stress analysis was calculated using Basquin's equation.

Results Calculated fatigue life was shorter in gold restored group than in controlled group and class II restored group showed shorter fatigue life than class I restored group. The shortest fatigue life was shown in class II gold restored tooth (3 X 107 years). For all cases, maximum stress was held in cold stimulation.

Conclusions The cyclic thermal stress is a contributing factor of tooth crack formation and the presence of restoration facilitates the fatigue failure caused by cyclic thermal stress.