Microdureza Vickers e grau de conversão em resinas ortodônticas

O objetivo deste estudo foi avaliar em diferentes resinas ortodonticas a microdureza Vickers e o grau de conversao. Quatro resinas foram utilizadas: Orthobond (OB), Ortholite (OL), Concise (CO) e Transbond XT (TB). Para cada resina, cinco amostras foram obtidas, nas quais foram realizadas trinta endentacoes em cada superficie no microdurometro Shimadzu (carga de 300 gramas/15 segundos). Para a avaliacao do grau de conversao, duas amostras de cada monomero e polimero foram obtidas e submetidas ao ensaio de FTIR pelo metodo de transmissao, com resolucao 2 cm-1 e 40 varreduras. Os resultados de microdureza Vickers (µHV) e grau de conversao (%) foram, respectivamente, para OB: 46 ± 17.52 (70% ±1.41), OL: 71 ±28.15 (61% ±3.53), CO: 76 ±32.70 (70% ±0.35) e TB: 73±28.40 (60% ±9.89). Os dados da µHV foram submetidos ao Teste de ANOVA e pos teste de Tukey, nao apresentando diferencas estatisticas significantes entre as resinas. O conhecimento das propriedades fisicas entre as resinas pode facilitar a escolha do material utilizado nos procedimentos ortodonticos. (AU) The aim of this study was to evaluate Vickers microhardness and the degree of conversion of different orthodontic resins. Four resins were used: Orthobond (OB), Ortholite (OL), Concise (CO), and Transbond XT (TB). For each resin five samples were obtained, in which thirty indentations were made on each surface in Shimadzu microhardness (300 grams/15 seconds). To assess the degree of conversion, two samples of each monomer and polymer materials were obtained and submitted to the test of FTIR Spectrophotometry by method of transmission, toned down with resolution 2 cm-1 and 40 scans. The results of Vickers microhardness (µ HV) and degree of conversion (%) were, respectively OB: 46 ± 17.52 (70% ± 1.41); OL: 71 ± 28.15 (61% ± 3.53); CO: 76 ± 32.70 (70% ± 0.35); TB: 73 ± 28.40 (60% ± 9.89). The data were submitted to ANOVA test and Tukey post-test, and no significant statistical differences were observed between the resins. The knowledge of the physical properties between resins can facilitate the choice of the material used in orthodontic procedures.