Translucency and colour masking ability of hybrid CAD/CAM materials with different thicknesses: in vitro study

To evaluate effect of material thickness and translucency of two different hybrid CAD/CAM materials on their masking ability.

40 rectangular-shaped specimens (12 × 14 mm) were obtained from Vita Enamic and Grandio blocks at 0.5 and 1 mm-thick (n = 10/group). Colour parameters of specimens were measured on PMMA tooth-coloured replica backgrounds (A2, C4) and black, white backings using dental spectrophotometer. Translucency parameter (TP) and masking ability (∆E₀₀) values of tested materials with 0.5, and 1 mm thicknesses were calculated. Quantitative variables were compared between groups using student t-test.

TP and ∆E₀₀ significantly decreased as thickness of tested materials increased. Grandio showed significantly higher TP values. There were significantly lower ΔE₀₀ values for Vita Enamic compared to Grandio at 1 mm thickness and inversely insignificant at 0.5 mm. The 0.5 mm-thick ∆E₀₀ of tested materials was above clinical acceptability threshold, whereas, 1 mm-thick did not exceed showing better masking properties.

Thickness is more effective for colour masking than translucency. In thin thickness, the masking ability is less effective, irrespective of tested materials. Translucency of tested materials was affected by their composition. Both hybrid CAD/CAM materials are promising alternatives for masking dark discolouration at 1 mm-thick.