Compression Behavior of Dental Flowable Composites-Digital Image Correlation and Numerical Analysis.

In the development of restorative materials, it is important to evaluate the elastic properties of the material in order to achieve good clinical results. The aim of this study was to evaluate the compression behavior of two dental flowable materials (EverX Flow and Flow-Art) using experimental methods and numerical simulation. The Poisson's ratio was determined using two methods of strain measurement: the electrical strain gauge method (ESG) and digital image correlation (DIC). Material constants determined in experimental studies were implemented in a numerical model, and displacement analysis was conducted using the finite element method (FEM). The tests showed higher compressive strength and modulus of elasticity for EverX Flow compared to Flow-Art. The values of the Poisson's ratio were similar for both measurement methods, ranging from 0.27 to 0.28 for EverX Flow and from 0.30 to 0.32 for Flow-Art. This demonstrated the feasibility of the DIC method for obtaining the Poisson's ratio values for this type of composites. Compression test conditions were reproduced in the numerical analysis. The obtained distributions of the displacement field on the surface of the sample from the DIC and numerical analyses were compared. A good match was observed between DIC displacement measurements and displacement values obtained in FEM analysis. The comprehensive approach used in the study allows us to analyze whether the results obtained in the numerical simulation correspond to the material response to the applied load and validate the model.