Influência do desenho da cavidade na microinfiltração marginal de restaurações cerâmicas tipo MOD

Abstract

O objetivo deste estudo foi avaliar a influência do desenho da cavidade na infiltração marginal de inlays cerâmicos.Foram confeccionados 30 cavidades classe II (MOD) em pré-molares, com término gengival mesial em esmalte e distal em dentina, obtendo-se as seguintes características: Grupo I: cavidades com divergência de 12º; Grupo II:cavidades com divergência de 18º; Grupo III:cavidades com divergência de 24º.Os inlays cerâmicos de IPS-Empress foram cimentados de acordo com as instruções do fabricante e submetidos ao teste de termociclagem. Após os testes estatísticos, concluiu-se que as divergências das paredes das cavidades, bem como a localização das margens (esmalte ou dentina) influenciam a microinfiltração de inlays cerâmicos confeccionados como sistema IPS-Empress. This in vitro study evaluates the influence of the cavity design on the microleakage of IPSEmpress ceramic inlays. Thirty extracted human bicuspids were selected and stored at room temperature. The specimens were randomly ascribed to three groups (n=10). Class II (MOD) cavities with gingival margins in enamel and dentin were prepared: Group I # 12° divergent walls; Group II - 18° divergent walls; Group III - 24° divergent walls. After the impressiontaking, IPS Empress® inlays (Ivoclar Vivadent) were fabricated according with the manufacturer#s instructions. The teeth were thermocycled (500 cycles, 5° to 55°C), sealed with nail varnish, immersed in a 0.5% basic fuchsin solution for 24 hours, embedded in epoxy resin, and cut in a mesio-distal direction. The sections were evaluated using a linear quantitative method (in mm) by three previously calibrated evaluators which used a software (ImageTool, San Antonio, TX, EUA). The results were statistically analyzed using one-way ANOVA and paired T-test. It was concluded that the walls divergence did not influence the degree of microleakage. Group I presented the highest microleakage values (p=0.0001), and Groups II and III did not present statistically significant differences (p=0.0022). Regarding the location of the gingival margin (enamel or dentin), the highest values were observed for dentin margins (p<0.0001). None of the groups was capable to reduce completely the marginal leakage.