Table 3. ΔE0, ΔE1 and ΔE2 values (mean ± SD) of the tested groups.

Groups	ΔE0	ΔE1	ΔE2	p+
OP	7.90 ±1.78Aa	2.56 ±1.13Ab	7.35 ±1.50Aa	<0.001*
PT	5.37 ±1.59Ba	3.49 ±2.12Ab	3.89 ± 0.82Bb	0.010*
WT	2.67 ± 0.92Ca	1.95 ±1.15Aa	2.36 ± 0.61Ca	0.221
WMR	3.52 ±1.08Ca	2.14 ±1.20Ab	2.69 ±0.96Cb	0.018*
WP	5.11 ±1.44Ba	2.60 ±0.93Ab	4.49 ±0.63Ba	<0.001*
p	<0.001	0.870	<0.001

Different letters, lowercase in rows for different times and uppercase in columns for different whitening products, indicate significant difference (p < 0.05).