Evaluation of translucency and strength of two glass ceramics after different surface treatments

Objective: To investigate the effect of different surface treatments on biaxial flexural strength and translucency of two different glass-ceramics. Materials and Methods: Sixty disc-shaped specimens (10 mm x 0.3 mm) were divided into two groups (n=30) according to the type of the ceramic material; lithium disilicate ceramic (IPS e.max CAD), and leucite reinforced ceramic (IPS Empress CAD). Each group was divided into three subgroups (n=10) according to the surface treatment applied; whether hydrofluoric acid etching, sandblasting, or no treatment. Translucency Parameter was measured over black and white backgrounds using dental spectrophotometer VITA Easyshade Compact, while bi-axial flexural strength was measured using a ball on ring fixture test. Data was statistically analyzed by ANOVA and Tukey’s post hoc analysis (α = 0.05). Results: There was a significant difference (P <0.05) in translucency parameter between all surface treatments used for IPS E.max CAD groups, while for IPS Empress CAD there was a significant difference (P < 0.05) in translucency between both the control and hydrofluoric acid groups as well as between hydrofluoric acid and sandblasted groups. There was no significant difference in bi-axial flexural strength between different types of surface treatments used for IPS E.max CAD. IPS Empress CAD groups showed a significant difference (P < 0.05) only between the control and the hydrofluoric acid groups. Conclusions: IPS E.max CAD had higher translucency and biaxial flexural strength. Different surface treatments used affected the flexural strength and translucency negatively in both materials used.