. 2018 Oct 2;26:e20170589. doi: 10.1590/1678-7757-2017-0589

Table 1. Mean values and standard deviations of relative areas of phosphate (PO₄ ^3-) peak v2 (431-449 cm^-1) (in arbitrary units) of FT-Raman spectra of sound and demineralized enamel at baseline (T₀) and after bleaching (T_b).

Treatments	Sound enamel				Demineralized enamel
	^T ₀		^Tb		^T ₀		^Tb
C	3.75	(0.12)^Aa	5.89	(0.92)^Ab	1.55	(0.47)^Aa ^*	6.49	(0.76)^Ab
HP	3.69	(0.18)^Aa	3.57	(0.33)^Ba	1.87	(0.92)^Aa ^*	4.79	(0.41)^Bb ^*
HPF	3.57	(0.17)^Aa	6.13	(0.59)^Ab	1.75	(0.75)^Aa ^*	6.36	(0.51)^Ab
HPC	3.46	(0.22)^Aa	6.89	(0.97)^Ab	1.98	(0.67)^Aa ^*	6.57	(0.12)^Ab

Mean values followed by distinct letters differ statistically at 5%, according to three-way ANOVA and Tukey test (p<0.05). Uppercase letters compare treatments (in columns) and lowercase letters compare time (in row).

Asterisks (*) compare each enamel condition within time

C: control

HP: 35% hydrogen peroxide

HPF: fluoride-based bleaching agent containing 35% hydrogen peroxide

HPC: calcium-based bleaching agent containing 35% hydrogen peroxide

Table 1. Mean values and standard deviations of relative areas of phosphate (PO4 3-) peak v2 (431-449 cm-1) (in arbitrary units) of FT-Raman spectra of sound and demineralized enamel at baseline (T0) and after bleaching (Tb).

Table 1. Mean values and standard deviations of relative areas of phosphate (PO₄ ^3-) peak v2 (431-449 cm^-1) (in arbitrary units) of FT-Raman spectra of sound and demineralized enamel at baseline (T₀) and after bleaching (T_b).