Efeito das propriedades mecânicas de materiais selantes na geração de tensões de contração em molares

Abstract

New resinous and ionomeric-resinous sealants are used as a method of preventing caries of posterior teeth through occlusal sealants. The study of the mechanical properties of sealants is extremely important. The objective of this work was to evaluate the post-gel contraction (SH), diametral tensile strength (TD) and axial compression (AC), Knoop hardness test (VHK) and modulus of elasticity, and 3D finite elements of sealants: Prev , Prevent (FGM); Fbf, Filtek Bulk Fill Flow (3M ESPE) and Vit, Vitremer (3M ESPE). Post-gel shrinkage of resinous materials was measured using the Extensometry method (n = 10). For the compression test, samples (n = 10) with 6mm of thickness and 3mm of diameter were made and for the test of traction with 4mm of diameter and 2mm of thickness. The tensile and compression tests were performed at a speed of 0.5 mm / min in a universal test machine. The test of Knoop hardness and modulus of elasticity was carried out to include the samples with polyester resin of cold inlay. To obtain the data a dynamic indenter of microhardness was carried out with penetrator of the type knoop, using a load of 500 g and one time of 10 seconds. For the finite element test a human molar tooth free of caries, cracks, structural defects or restorations was selected. The tooth was submitted to scanning in a computerized microtomography apparatus. To perform the segmentation of the dental element Mimics software was used and soon afterwards to obtain the mesh, the MARC / MENTAT software was used to achieve a level of greater regularity and homogeneity among the surface elements. For the final analysis of each model with its sealant material the modified von Mises technique was used. Data were analyzed by ANOVA and Tukey's test (α = 0.05). SH values were: Prev, 0,56 ± 0,09, Fbf, 0,47 ± 0,07 e Vit, 0,18 ± 0,006. 251.8 ± 36.1 A; Fbf, 245.1 ± 30.6 A; Vit, 121.6 ± 15.7. The values TD (MPa) were: Prev, 35.6 ± 3.7 A; Fbf, 38.6 ± 7.5 A; Vit, 15.7 ± 8.2 B. VHK values were: Prev 48.1 ± 1.47, Fbf 39.6 ± 1.75; Vit 38.9 ± 1.76. It was concluded that the bulk fill resin presented values similar to the resin sealant prevent and higher than the vitremer resinous ionomer, which may be the best choice material according to the presented results.