. 2012 Mar-Apr;20(2):186–191. doi: 10.1590/S1678-77572012000200011

Table 1.

Tooth shade means and standard deviations (±SD) for the different treatment groups according to the evaluation periods

Treatment groups	Evaluation periods
	T0 (baseline)	T1 (1-week of treatment)	T2 (1-week after treatment)
Control	^A12.9 (±1.7)^a	^A12.4 (±1.3)^a	^A 12.5 (±0.7)^a
CP10	^A12.7 (±2.6)^a	^B4.4 (±2.1)^b	^C2.9 (±0.7)^b
CP16	^A12.7 (±1.8)^a	^B4.1 (±2.2)^b	^C2.3 (±1.3)^b
CP37	^A11.8 (±2.5)^a	^B7.0 (±3.2)^c	^C2.4 (±0.6)^b

Different capital letters indicate statistically significant differences only among the evaluation periods (p<0.001). Different lowercase letters indicate statistically significant differences only among the treatment groups (p<0.001).