The placebo gel (PG) (natrosol 4%) will be applied to the buccal surfaces of the central and lateral incisors, canines and upper and lower premolars, with a microbrush actively, for 10 minutes. Subsequently, all groups will undergo in-office whitening treatment with 35% hydrogen peroxide (Whiteness HP, FGM). Sensitivity assessment will be carried out using a form consisting of a visual analogue scale (VAS), patients will be instructed to record tooth sensitivity daily, during the 21 days of follow-up. To measure color, the VITA Easyshade spectrophotometer (VITA, Germany)) will be used at two times: baseline (Ti) and one week after the 3rd bleaching session (Tf).

gel with 5% potassium nitrate and 2% sodium fluoride The gel with 5% potassium nitrate and 2% sodium fluoride (NKFG) will be applied to the buccal surfaces of the central and lateral incisors, canines and upper and lower premolars, with a microbrush actively, for 10 minutes. Subsequently, all groups will undergo in-office whitening treatment with 35% hydrogen peroxide (Whiteness HP, FGM). Sensitivity assessment will be carried out using a form consisting of a visual analogue scale (VAS), patients will be instructed to record tooth sensitivity daily, during the 21 days of follow-up. To measure color, the VITA Easyshade spectrophotometer (VITA, Germany) will be used at two

The experimental 2% cannabidiol gel (GCBD) will be applied to the buccal surfaces of the central and lateral incisors, canines and upper and lower premolars, with an active microbrush, for 10 minutes. Subsequently, all groups will undergo in-office whitening treatment with 35% hydrogen peroxide (Whiteness HP, FGM). Sensitivity assessment will be carried out using a form consisting of a visual analogue scale (VAS), patients will be instructed to record tooth sensitivity daily, during the 21 days of followup. To measure color, the VITA Easyshade spectrophotometer (VITA, Germany) will be used at two times: baseline (Ti) and one week after the 3rd bleaching session (Tf).

Gel with 5% potassium nitrate and 2% sodium fluoride gel of 5% potassium nitrate and 2% sodium fluoride for topical application to teeth before bleaching with hydrogen peroxide

Experimental cannabidiol and gel (experimental group) and potassium nitrate gel (control group) can change sensitivity related to tooth whitening with hydrogen peroxide 35%. So it is necessary measure this pain. The volunteers will mark on the scale (VAS) the level (1-10) of sensitivity immediately after the intervention, and for a period of 21 days of treatment.

Silicone trays will be made, with canine-by-canine impressions. A window will be created on the vestibular surface of each canine of the silicone guide using a metal device with a radius of 6 mm, corresponding to the diameter of the spectrophotometer tip. The tip of the device will be inserted into the silicone guide to obtain the color parameters of the CIEL*a*b* system, where L* represents the value (light or dark); a* is a measurement of red (a* positive) or green (a* negative); b* is a measurement of yellow (b* positive) or blue (b* negative). The sum of the measured values of the upper canines will be used to obtain the averages of each L*a*b* coordinate for each patient. ΔL*, Δa* and Δb* will be calculated by the difference between the time intervals. Subsequently, the color difference between baseline (Ti) and one week after the 3rd bleaching session (Tf) will be calculated using the CIEDE2000 formulas (ΔE00).