Flexural strength and elastic modulus evaluation of structures made by conventional PMMA and PMMA reinforced with graphene

Abstract. – OBJECTIVE: The aim of this study was to compare both the elastic modulus (EM) and the flexural strength (FS) of two materials used in dental prosthesis, namely polymethylmethacrylate (PMMA) and polymethylmethacrylate reinforced with graphene (G-PMMA). MATERIALS AND METHODS: Twenty rectangular samples were manufactured by a milling machine and divided into two groups (n= 10/group): Group 1, PMMA; Group 2, G-PMMA. The specimens were subjected to a three-point bending test conducted in the elastic range to evaluate EM. A similar test was protracted until fracture to evaluate FS. Data on EM and FS were statistically analyzed with independent-samples t-test in order to compare the two groups. A scanning electron microscope (SEM) (5.00 kx and 1.00 kx magnification) was used to evaluate the morphology of sample’s fracture. RESULTS: Compared to PMMA samples, each G-PMMA sample showed significantly higher values of FS (p <0.001) and EM (p <0.001). SEM images analysis showed an inhomogeneous fracture morphology in G-PMMA samples. CONCLUSIONS: The results show that G-PMMA is a promising material to be used for prosthetic purposes. This is demonstrated by a significant increase in both peak load and bending stiffness, resulting from the bending test performed on G-PMMA samples. Furthermore, the latter exhibit greater homogeneity in their mechanical behavior, supporting the potential value of this material in dental prosthesis.