ABSTRACT
Objectives: To evaluate different surface treatments influence on optical properties of two CAD/CAM lithium silicate-based ceramics.
Materials & Methods: Sixty disc shaped samples (10 mm diameter x1mm thickness) were constructed and divided according to ceramic type into two groups (30 samples/group): Group(LD):Lithium disilicate. Group (ZLS): Zirconia reinforced-lithium silicate. Each group was divided into three sub-groups (10 samples/subgroup), according to the surface treatment:(C) Control, (HF) Hydrofluoric acid 9.5%, (SB) Sandblasting. Spectrophotometer was used to measure both Colour change (ΔE) & Contrast Ratio (CR). Universal adhesive was added to sub-groups (HF) & (SB) then (ΔE) & (CR) were measured for the new subgroups (HFU & SBU). Finally, collected data were statistically analysed.
Results:(∆E) showed significant increase within (LD) for both subgroups (HFU & SBU). ZLS (Subgroup SBU) showed a significantly higher ∆E compared to the other subgroups. In both groups, the highest ∆E was recorded for the (SBU subgroups). (CR) showed an insignificant difference within (LD) group. Only ZLS (HF) & (SB) subgroups recorded significant difference with all the other subgroups in both groups & insignificant difference with each other.
Conclusions: Etching or sandblasting without the use of universal adhesive didn't affect the colour of (LD) as ∆E lied in the range of clinical acceptance. Etching or sandblasting (LD) with or without the use of universal adhesive didn't affect its translucency. Etching (ZLS) with the use of universal adhesive didn't affect its colour nor its translucency.