Performance biomecânica e caracterização do protetor bucal em implante dentário frente à impacto análise experimental e elementos finitos

Abstract

The aim of this study was to characterize the mouthguard material and evaluate mouthguard shock absorption, impact strain and stress behavior in an impact on dental implants inserted in the anterior maxilla. Sixty models were manufactured which were randomly divided into six groups (n=10) varying: implant type, EH external hexagon (Alvim Smart, NEODENT), and MT, Morse taper (Alvim CM, NEODENT); mouthguard type: custom-fitted with two sheets of EVA (BioART), standard self-adapted (Dogma Indútria e Comércio de Plásticos Ltda) and without mouthguard. To characterize the mouthguard material Shore A hardness and thickness of EVA sheets, transparent and pink, and mouthguard were measured. To characterize the deformation of the implant front impact, strain gauge was attached at the palatal surface of the implant abutment and samples were submitted to the impact test at 45° directed in the central buccal side of the crown. Abutment/implant distortion after the impact was calculated by the centroid in standardized XR-images. Six two-dimensional finite element models were created and submitted to nonlinear dynamics analysis of impact, with parameters and factors similar to the strain gauge test. The data were statistically analyzed using factorial analysis of variance and Tukey test (α=0.05). There was no significant difference in Shore A hardness between pink and transparent sheets (P=0.796). Standard self-adapted mouthguard expressed Shore A hardness lower than custom-fitted (P<0.001). The sheet thickness presented standardization of industrial construction. After heat forming process the standard self-adapted mouthguard kept the initial thickness, but the custom-fitted mouthguard suffered significant reduction. The mouthguard presence reduced significantly the strain values (P<0.001), especially the custom-fitted, there is no significant difference between the implant connection type (P=0.547). After impact, there was micro displacement in the implant/abutment, which was more pronounced in the absence of mouthguard use. Implant EH resulted in higher values of stress and strain. The mouthguard shock absorption was 40 to 46% and increased the time of contact of the sphere on impact by reducing the peak of the stress.