At-home Bleaching Using Clear Retainers

The inclusion criteria will be the following: * Patients over 18 years of age. * Patients with vital teeth without restorations, single crowns, implants and/or bridges at the level of the anterior teeth. * Absence of cavities in the teeth to be whitened. * Patients with satisfactory oral hygiene, and periodontally healthy, who are not undergoing periodontal maintenance and who do not use chlorhexidine rinses. Patients with recessions without sensitivity are included. * Absence of sensitivity, measured based on stimulation with the air from the syringe. * Patients who are at least in A2-A3 color (Vita Classic Guide) The exclusion criteria will be the following: * Patients who have previously undergone whitening (less than 5 years). * Patients undergoing orthodontic treatment. * Patients with white spot or developmental alterations (dentinogenesis imperfecta, amelogenesis imperfecta) or with stains (tetracyclines or fluorosis). * Patients with a history of trauma to anterior teeth. * Patients who require internal whitening. * Smokers. * Pregnant or lactating women. * Allergy to any component of whitening. * Alterations of the oral mucosa (desquamative gingivitis, OLP, leukoplakias, etc.). * Medical conditions considered by the researchers that may compromise the study or the individual safety of the patient. * Patients with poor oral hygiene. * Patients with previous hypersensitivity.