Participants: Patients included in this clinical trial will be at least 18 years old with good oral health. Patients with any of the six upper anterior teeth with caries, restoration, severe discoloration (e.g., stains caused by tetracycline), enamel hypoplasia, gingival recession, dentin exposure, pulpitis, or endodontics will be excluded. Participants submitted to previous bleaching procedures, presenting prior tooth sensitivity, pregnant or breastfeeding will be also excluded. Only patients presenting all six upper anterior teeth with shade mismatching with 2.5 M2 (Vita Bleach guide 3D-Master scale, Vita-Zahnfabrik, Bad Sackingen, Germany) or darker will be included.