. 2026 Mar 2;34:e20250513. doi: 10.1590/1678-7765-2025-0513

Table 2. Mean (standard deviation) of color variation variables measured by reflectance spectrophotometry across different groups.

Group	∆L*	∆a*	∆b*	∆E_ab	∆E₀₀	∆WID
No bleaching	−1.10 (0.63)^A	0.20 (0.27)^A	4.98 (5.76)^A	1.56 (0.77)^A	1.77 (0.79)^A	−3.18 (8.68)^A
7.5% HP	6.46 (1.93)^B	−0.78 (0.77)^B	−22.78 (5.07)^B	25.46 (5.16)B	13.04 (4.00)^B	28.52 (29.23)^B
7.5% HP + Chi	6.84 (1.96)^B	−0.64 (0.58)^B	−24.03 (5.37)^B	27.25 (6.37)B	13.08 (4.25)^B	40.15 (17.54)^B
7.5% HP + Ca	6.08 (1.57)^B	−0.75 (0.88)^B	−22.09 (5.14)^B	24.88 (4.10)B	13.46 (4.56)^B	32.69 (26.88)^B
7.5% HP + Ca + Chi	6.05 (2.28)^B	−0.60 (0.84)^B	−25.53 (5.51)^B	24.61 (6.27)B	14.22 (4.92)^B	37.15 (27.42)^B
p-value	<0.0001	0.0019	<0.0001	<0.0001	<0.0001	<0.0001

Distinct letters (comparing the groups in each variable) indicate statistically significant differences (p≤0.05).