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• Published in: Brazilian dental journal 2007, Vol.18 (4), p.324-328
• Main Authors: Coto, Neide Pena, Dias, Reinaldo Brito e, Costa, Ricardo Aurélio, Antoniazzi, Tatiana Fioresi, Carvalho, Eduardo Pena Coto de
• Format: Article
• Language: English
• ISSN: 0103-6440; 0103-6440
• DOI: 10.1590/S0103-64402007000400010

In the present investigation, an experimental dental arch model fabricated in epoxy was assayed in Kratos universal testing machine to study the mechanical behavior of ethylene and vinyl acetate copolymer (EVA) in the form of mouthguard for sports and flat plate. The following variables were considered: thickness (3 and 4-mm plates), temperature (room and mouth temperature) and presence/absence of artificial saliva. Mechanical properties of EVA were tested under compressive strength: apparent absorbed energy (J.mm-1), maximum tension (N.mm-1), maximum dislocation (mm) and maximum strength (N). Data were recorded and modeled mathematically. Regarding the absorbed energy, maximum tension and maximum force, it was verified that the higher the thickness of the mouthguards, the better the results of force dissipation and redirection to the system and to several regions of the dental arch. In the presence of saliva and close to mouth temperature, the material responded positively to these alterations, resenting increased ductibility as well as improved mechanical responses. Regarding maximum dislocation, it was observed a better accommodation of the occlusion under conditions that simulate those observed in the oral environment. In conclusion, EVA proved to be an adequate material for fabrication of mouthguards and interocclusal splints. In addition, EVA showed good results in force dissipation and demonstrated a shock-absorbing capacity and a great protection potential. Um modelo experimental de arco dentário, obtido em epóxi, acoplado a uma máquina universal de ensaios Kratos, foi utilizado para estudar o comportamento mecânico do copolímero de etileno e acetato de vinila (EVA), na forma de protetor bucal para esporte e placa plana. As seguintes variáveis foram observadas: espessura (lâminas de 3 e 4 mm), temperatura (ambiente e bucal) e presença ou ausência de saliva artificial. As propriedades mecânicas do EVA, foram testadas ao esforço compressivo: energia aparente absorvida (J.mm-1), tensão máxima (N.mm-1), deslocamento máximo (mm) e força máxima (N). Dados foram registrados e modelados matematicamente. Considerando a energia aparente absorvida, tensão máxima e força máxima, verificou-se que com o aumento da espessura dos protetores bucais houve melhores resultados de dissipação de forças compressivas e seu redirecionamento para o sistema e diversas regiões do arco dental. Com a presença de saliva e temperatura próxima a bucal o material respondeu positiva