Influência da espessura da camada de opaco na capacidade de mascaramento de metalocerâmicas

• Autor(a) principal: Pieper, Cari Maristela
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFPel - Guaiaca
• Texto Completo: http://repositorio.ufpel.edu.br/handle/ri/2275
• topic: Ligas metalo-cerâmicas; Cerâmica opaca; Opacidade; Metal-ceramic alloys; Ceramic opaque; Opacity; CNPQ::CIENCIAS DA SAUDE::ODONTOLOGIA

The aim of this study was to evaluate the ability of two ceramic opaque masking applied in different thicknesses in a metallic substrate. 80 Ni-Cr (High Bond) metalic discs were fabricated, each with 1.6 mm diameter and 1 mm thickness, by lost wax technique. After disks obtaining, they were divided into 8 groups (n = 10) and opaque ceramic (Noritake) "paste" (groups 1 to 4) and "powder" (groups 5 to 8) was applied with a camel hair brush and distilled water. The opaque layers were machined with aluminum oxide burs to achieve the following thickness: G1 = G5 and 0.10 mm thick; G2 and G6 = 0.15 mm; G3 and G7 = 0.20 mm and G4 and G8 = 0.30 mm thick. Than opaque dentin ceramic was applied (two sintering cicles, totaling 0.7 mm) and glazed. The color was evaluated with the aid of a portable spectrocolorimeter (Konica - Minolta CR-10), which registered the color of specimens in the CIE L*a*b* scale. The absolute values of L *, a * and b * were statistically analyzed as isolated variables.The ΔE were also analyzed, considering the mean values of L * a * b * in the control group (G4) as reference values. Once data showed normality and homogeneity, it were applied 2-way ANOVA and Tukey s complementary test, when needed, with p < 5%. Results: Powder opaque presented statistically significant greater values in (L*) and (ΔE) and the reverse happened to other two variables. Analysing opaque thickness, values may be grouped as followed: (L*) variable: (0,10mm = 0,15mm) < (0,20mm = 0,30mm); (a*) variable: (0,10mm) < (0,15mm = 0,20mm) < (0,30mm); (b*) variable showed no statistically significant differences; (ΔE) variable: (0,10mm) < (0,15mm = 0,20mm = 0,30mms). It could be concluded that paste and powder opaque have different behavior and all thickness, except 0,10 mm, may be used without significant color change