Table 2. Masking ability of the zirconia specimens on the Co-Cr alloy substrates.

		Thickness (mm)
		0.7	1.0	1.2	1.5
Shade of zirconia	1M1		Oa < Ba	B	Oa < Ba
	1M2
	2M1	Y	Ya < Tb < Wc	Ta < Yb < Ob	Ta < Ob < Bc < Yd < Wd
	2M2
	2M3			Wa < Ob < Yb < Bc	Ba < Ob < Tb < Yb < Wc
	3M2				Oa < Bb < Tc < Yd < We
	4M2				Wa < Oa < Yb < Bb,c < Tc
	5M2	O		Oa < Yb < Tb < Bb < Wc	Oa < Ba,b < Yb < Tc < Wd

^*W(w), Y(y), T(t), B(b) and O(o), respectively, represent the ΔE values of different groups using try-in pastes in shades of white, yellow, transparent, bleach and opaque; Capital letters (W, Y, T, B, O) mean 2.6 ≤ ΔE < 5.5; Lowercases (w, y, t, b, o) mean ΔE < 2.6; Same superscripts represent no statistical difference between the groups.