Table 1. Bleaching agents tested, their chemical characteristics and manufacturers.

Group	Bleaching agent	Chemical characteristics	Manufacturers	Application technique
At-home	White Perfect	10% Carbamide Peroxide Potassium nitrate Sodium fluoride	FGM	2 hours per day for 14 days
In-office	White HP Blue	35% Hydrogen Peroxide Thickeners Violet Pigment Neutralizing agents Calcium Gluconate Glycol Deionized Water	FGM	one application of 40min for week 2 weeks
Placebo At-home		Carbopol® 940 (10g) Distilled water (11g) AMP 95 (1g)	Drugstore	2 hours per day for 14 days
Placebo In-office		Carbopol® 940 (10g) Distilled water (11g) AMP 95 (1g) Violet Pigment (0,5g)	Drugstore	one application of 40min for week 2 weeks

Potassium nitrate desensitizing gel (Desensibilize KF2%, FGM, Brazil) was applied for 10 minutes on the labial surface for both groups in the first section