A 3D finite element analysis of stress in the interphase of restoration-tooth structure due to polymerization shrinkage

Shuiwen Zhu, MS, Jianping Fan, PhD, and Cheng Wang, PhD

School of Civil Engineering and Mechanics, Huazhong University of Science and Technology, Hubei Key Laboratory for Engineering Structural Analysis and Safety Assessment, Wuhan, P. R. China

Purpose: The purpose of this paper is to investigate the influence of interphase properties on restored tooth structure due to polymerization shrinkage of resin-based composite.
Materials and Methods: A 3D finite element analysis was performed. The restoration-tooth interface was simulated using solid elements of varying material properties and thicknesses. The stress within the restored tooth structure built up from the polymerization shrinkage of the restorative composite was computed accounting for the time-dependent and visco-elastic behavior of the composite.
Results: It was found that a correlation exists between material and geometry properties at the restoration-tooth interface and higher shrinkage stresses were located at the interphase due to polymerization shrinkage. The development trend of residual stress from polymerization shrinkage in the restored-tooth structure was predicted.Conclusion: The varying material and geometry properties of restoration-tooth interface seemed to have a conclusive effect on the interfacial stress system, as well as on the longevity of the restoration. From the purely mechanical point of view, this can result in interfacial debonding. (Int Chin J Dent 2009; 9: 1-8.)

Key Words: composite restoration, finite element analysis, interphase, polymerization shrinkage.