To evaluate the effectiveness in terms of color variation, patient satisfaction, absolute risk and intensity of dentin sensitivity due to dental bleaching in the office with 35% hydrogen peroxide (Whiteness HP Automixx 35%, FGM) and Opalescence Boost 38% ( Ultradent, South Jordan, UT, USA) in the same arch in patients of different age groups: 18 to 25 years and 40 to 65 years. Data will be collected, tabulated and submitted to statistical analysis

Throughout life, the aging of the human being as a whole is inevitable. The dental structure such as cementum and dentin undergo some changes over time, such as secondary deposition of dentin, which results in the reduction of root canal length. In addition, with aging the teeth undergo color changes, presenting a more yellowish or grayish coloration (Ravindra SV et al., 2015). The fact is that most of the studies that involve the technique of dental bleaching have as inclusion factor only young adult patients, excluding patients of more advanced age groups. Therefore, it is fundamental to evaluate the whitening technique in these older patients, since it is a treatment that does not cause harm to the individuals To assess the effect of dental bleaching in the office with Whiteness HP Automixx, FGM at 35% and Opalescence Boost at 38% in the same arch, in different age groups (18 to 25 years and 40 to 65 years) in absolute risk and intensity Of the postoperative dental sensitivity through the visual analog (VAS 0-10) and analogue (NRS 0-4) scales.

• Evaluate the efficacy of Whitening HP Automixx, FGM 35% and Opalescence Boost 38% in the same arch in different age groups (18 to 25 years and 40 to 65 years) using Color Vita Classical and Vita Bleachedguide, and the Vita Easyshade spectrophotometer.
• Evaluate the satisfaction of patients after Whitening HP Automixx at 35, FGM and Opalescence Boost 38% in the same arch in different age groups (18 to 25 years and 40 to 65 years).

Inclusion Criteria:

• Patients over 18 years of age up to 25 years
• Patients aged 40 years up to 65 years
• Good oral and general health
• Teeth free of restorations or with small restorations
• Free from carious injury,
• Patients with tooth color A2 or darker according to the Vita Classical color scale (Vita Zahnfabrik, Bad Säckingen, Germany)
• Agree to the informed consent form

Exclusion Criteria:

• extensive restoration
• Patients who have already undergone dental whitening
• Pregnant or lactating women
• That report dental sensitivity
• With non-carious cervical lesion
• Parafunctional habits
• Orthodontic appliances
• Any other type of oral pathology
• Smokers, patients who are using analgesic or anti-inflammatory drugs, present systemic alterations such as gastric, cardiac, renal and hepatic problems, diabetics, hypertensives or pre-existing neoplasias.

the patient did not know in which region each gel was applied the investigator did not know in which region each gel was applied the outcomes assessor did not know in which region each gel was applied