A literature review on the linear elastic material properties assigned in finite element analyses in dental research

Finite element analysis (FEA) is a numerical procedure utilised in the engineering analysis of structures and is one of the most common numerical methods utilised in many research activities in dentistry such as implantology, prosthodontics and restoration. FEA can be considered a useful tool in order to describe the deformation aspects of dental components that cannot be measured easily by in vivo models. The geometry, material properties, finite element model (mesh structure) and boundary conditions defined for a particular FEA setup are the factors affecting the accuracy of the results of a FEA. Most especially, material models employed in FEA play a critical role, however, the literature cannot provide standard material models and data in agreement to be defined in the FEA studies handled specifically for human teeth. The aim of this study is reviewing the most utilised data related to material properties (limited to linear homogeneous isotropic material model) of the tooth components, evaluate the sources and reasons for the different values defined in dental research and provide filtered material data which can be utilised in related FEA studies. Electronic databases (PubMed and Web of Science) were reviewed for publications on FEA utilised in dentistry research. 155 research publications in total were considered in this paper. The search keywords of “finite element analysis”, “finite element study”, “mechanical properties” and “teeth” were combined through Boolean operators. The primary question under review was: “How were the material properties of the tooth components and numerical ranges, which are assigned in a FEA utilised in dental research, obtained and verified?”. It was possible to determine sixteen different elastic modulus (EM) and seven Poisson’ ratio (PR) values for enamel, eighteen EM and five PR values for dentin, sixteen EM and four PR values for periodontal ligament, eight EM and one PR values for pulp, ten EM and five PR values for cementum, twelve EM and four PR values for cortical bone, and eleven EM and four PR values for cancellous bone. As a result, it was seen that various EM, PR, density and strength values were considered and these were obtained from a limited number of FEA studies. Average ranges for the core material properties such as EM, PR, density and strength values to be utilised in a FEA set up were presented. Further studies, specifically on determination of the mechanical properties of tooth components are still needed in order to successfully utilise them and confirm the accuracy of the FEA studies related to dental research.