Acceptance of lip retractors in in-office tooth bleaching

INTERVENTION: This is a randomized, four‐arm, non‐blinded crossover clinical trial. 56 participants will be allocated using block randomization to determine the sequence of 4 different lip retractors (n=56). Each participant will use all 4 retractors according to the randomized sequence. The same bleaching agent (35% hydrogen peroxide) will be used in all treatment sessions. The study protocol will consist of 4 clinical sessions, with a 7‐day interval between sessions, and a different lip retractor will be used at each session according to the predetermined randomized sequence. CONDITION: C07.793.266 Tooth Discoloration; posteruptive colour changes of dental hard tissues ; Dentin Sensitivity PRIMARY OUTCOME: To evaluate patient comfort with the use of different lip retractors through a series of questions using the VAS scale (0–10) during in‐office bleaching. The values will be presented as mean and standard deviation. SECONDARY OUTCOME: Assess the absolute risk of gingival irritation. Patients will be expected to report irritation at some point or up to 48 hours after each session using the VAS visual analogue scale (0 to 10). The percentage of patients with pain will be called the absolute risk of gingival irritation. Assess the absolute risk of tooth sensitivity. Patients will be expected to report spontaneous pain at some point or up to 48 hours after each session, using the VAS visual analogue scale (0 to 10). The percentage of patients with pain will be called the absolute risk of tooth sensitivity. Evaluate Aesthetic Self‐Perception using the Orofacial Aesthetic Scale (OEE) before, and after the completion of the procedure. Evaluate the intensity of dental sensitivity through the records made by the patients using the visual analogue VAS scale (0 to 10). Values ??will be presented as mean and standard deviation. Evaluate the intensity of gingival irritation through the records made by patients using the VAS visual analogue scale (0 to 10). Values ??will be presented as mean and standard deviation. Evaluate the use of lip retractors by the professional through a sequence of questions using the VAS scale (0–10) during in‐office whitening. The values will be presented as mean and standard deviation. The color difference between the initial condition and 1 month after whitening will be evaluated using the Vita Classical and Vita Bleachedguide shade guides, as well as the Vita Easyshade spectrophotometer. The data will be presented as means and standard deviations. The impact of oral condition on quality of life will be evaluated using the Brazilian version of the short form of the Oral Health Impact Profile (OHIP‐14), which contains 14 questions, before and after the completion of the whitening procedure. The values will be presented as mean and standard deviation. INCLUSION CRITERIA: Age between 18 and 60 years; good general and oral health; vital healthy teeth; minimum color A2; agree and sign the informed consent form (TCLE)