 - Participants that had undergone previous dental bleaching procedures during orthodontic treatment, or those that were pregnant or lactating women and participants with bruxism habits, were not included in the trial. Additionally, participants with restorations on the labial surfaces of their anterior teeth and non-carious cervical lesions, veneers or full crowns, with gingival recession, spontaneous tooth pain, internal tooth discoloration, and teeth with endodontic treatment or fluorosis were also excluded from this trial 