Rugosidade, microdureza e resistência à flexão de resinas acrílicas utilizadas para confecção de placas miorrelaxantes: estudo in vitro

Abstract

The mechanical properties of the materials used in interocclusal splints are important to prevent the accumulation of biofilm, promote splint longevity and, ultimately, ensure effectiveness of the splint in treating temporomandibular disorders. The aim of this study was to evaluate the roughness, microhardness and flexural strength of self-cured, heat-cured and three-dimensionally printed acrylic resins used to construct interocclusal splints. Forty-five bars, 45 cubes, and 45 disks were divided into 3 groups (n = 15), according to the type of acrylic resin used to make them, to evaluate their flexural strength, Knoop microhardness, and roughness, using a universal testing machine, a digital microhardness tester, and a surface roughness tester, respectively. One-way analysis of variance was used to analyse the data (p < 0.05). The roughness, microhardness, and flexural strength observed for the selfcured, heat-cured, and 3D-printed resins were 1.72 µm, 22.1 Kg/mm2 , and 21.63 MPa; 1.52 µm, 20.8 Kg/mm2 , and 14.79 MPa; and 1.57 µm, 20.5 Kg/mm2 , and 17.86 MPa, respectively. There were no significant differences between the materials tested (p > 0.05). It was concluded that the tested resins had similar mechanical behavior and roughness, within the parameters expected for use in the construction of interocclusal splints.