Finite element simulation of fixed dental prostheses made from PMMA —Part II: Material modeling and nonlinear finite element analysis

Abstract

Material characteristics can change significantly with increasing chewing velocity. As these in-vitro examinations are very timeconsuming and cost-intensive, the application of finite element analysis (FEA) offers a suitable alternative for predicting the material behavior of complex specimen geometries under clinically relevant loads. Although FEA is applied within numerous dental investigations, there are only few studies available in which a nonlinear FEA is validated with real experiments. Therefore, the aim of the present study was to predict the mechanical behavior of a clinically close three-unit temporary bridge composed of polymethyl methacrylate (PMMA) in the left upper jaw with nonlinear FEA and to verify the prediction through validation experiments. In conclusion, simplifying assumptions of linear elastic material properties for polymeric materials should be avoided in FEA studies, because rate dependencies, stress relaxation and plastic flow are not considered. Additionally, precise preliminary investigations for material characterization are necessary.

Comparative Analysis of the Structural Weights of Fixed Prostheses of Zirconium Dioxide, Metal Ceramic, PMMA and 3DPP Printing Resin—Mechanical Implications

“…This study shows that PMMA exhibits predominantly linear behavior compared to the other analyzed structures, exhibiting stress relaxation, plastic deformation and a modulus of elasticity dependent on the load and rate of load application. The plastic deformation of PMMA under different degrees of pressure could improve the obtained results; although, this would considerably increase the experimental stress, which is why it is necessary to implement compression tests [43]. The 3D FEA simulation used in this study confirmed that a heavier and stiffer material is not more resistant to forces or deformations, since it transfers more stresses to supporting structures, while the opposite occurs with more flexible and resilient materials [44].…”

A statistical model of the rate-dependent fracture behavior of dental polymer-based biomaterials

“…This target can then be used to select a failure criterion of fracture strains at different strain rates from the proposed P(ε,ε̇) model, similar to the previously described application. By simulating the desired component (akin to Schrader et al 17) ) at the expected boundary conditions (i.e., chewing velocity and chewing force in the case of a dental restoration), one obtains an indication of whether the planned supply can withstand the expected load . If the simulated component happens to fracture, the restoration must be redesigned; otherwise, the planned restoration can be manufactured.…”

“…The tests are conducted on polymer-based biomaterials to ultimately increase patient safety and comfort by predicting the failure probability of restorations in consideration of rate-dependent material behavior. An implementation of finite element models, such as the simulation of dental prostheses by Schrader et al 17) is deemed worthwhile. It should be noted in advance that although we focused on dental PMMA in this study, the methodology developed in this study is considered usable for all kinds of above-mentioned dental biomaterials and other thermoplastics.…”

“…2, 25-29 for example), it has so far been mostly neglected in dental biomaterials science. Only recently, new studies have been investigating the influence of the rate-dependency on the behavior of provisional treatments consisting of PMMA, with the conclusion that the rate-dependency of PMMA must not be neglected because the fracture behavior of a provisional treatment consisting of PMMA is heavily impacted by the loading velocity 17,24,30) . As thermoplastics generally behave in this manner, it is likely that the same also applies to many other polymer-based materials or hybrid materials with a thermoplastic matrix, used in the medical field.…”