Comparison of different in-office tooth bleaching techniques

INTERVENTION: This study is a prospective, randomized, parallel‐group, single‐blind clinical trial that will be conducted at the Dental Clinics of the State University of Ponta Grossa (UEPG), Brazil. The study has been approved by the Institutional Research Ethics Committee and will be conducted in accordance with the CONSORT guidelines for non‐inferiority trials. Participants will be recruited through an electronic form advertised on social media platforms and the university's official communication channels. Eligible participants must be 18 years of age or older, in good general and oral health, present no carious lesions, extensive restorations, fractures, or endodontic treatment in the si Xmaxillary anterior teeth, and have maxillary canines with an initial shade of A2 or darker according to the Vita Classical Shade Guide. Exclusion criteria include pregnancy or lactation, smoking, anterior prosthetic restorations, fixed orthodontic appliances, severe fluorosis, tetracycline staining, pre‐existing dentin hypersensitivity, severe bruxism, active periodontal disease, and continuous use of analgesic, anti‐inflammatory, or desensitizing medications. A total of 100 participants will be enrolled and randomly allocated by an independent researcher using computer‐generated randomization and sequentially numbered, opaque, sealed envelopes to ensure allocation concealment. Participants will be assigned to one of four experimental groups: Group 1, White Clinic Calcium 35% applied for 45 minutes; Group 2, White Clinic Calcium 35% applied for 25 minutes; Group 3, White Clinic 35% applied in three consecutive 15‐minute applications; and Group 4, White Clinic 35% applied in three consecutive 8‐minute applications. Before the bleaching procedure, dental prophylaxis, relative isolation, and gingival protection using a light‐cured resin barrier will be performed. All bleaching agents will be handled according to the manufacturers' instructions, and participants will receive standardized postoperative instructions, including information regarding potential risks, benefits, and the recording of tooth sensitivity and gingival irritation.Bleaching efficacy will be assessed using a Vita Easyshade spectrophotometer and the Vita Classical and Vita Bleachedguide 3D‐MASTER shade guides at baseline, and after 7, 14, and 21 days, as well as 30 days after treatment. The outcomes to be evaluated include ?E00, ?Eab, Whiteness Inde Xfor Dentistry (WID), Shade Guide Units (SGU), tooth sensitivity, gingival irritation, and patient satisfaction. Data will be statistically analyzed using a significance level of 5%, and the findings will subsequently be disseminated through peer‐reviewed scientific journals. CONDITION: C07.793.266 Hidrogen Peroxide ; Dentin Sensitivity PRIMARY OUTCOME: To evaluate the bleaching efficacy and the risk of tooth sensitivity in patients undergoing in‐office dental bleaching with 35% hydrogen peroxide gels with different formulations and application times SECONDARY OUTCOME: To analyze the relationship between bleaching efficacy and clinical comfort across the different protocols tested To compare the bleaching efficacy of the gels, assessing the possible influence of calcium To evaluate the impact of reducing the application time on bleaching efficacy To evaluate the impact of reducing the application time on the occurrence and intensity of tooth sensitivity To evaluate whether the addition of calcium to White Clinic Calcium 35% gel reduces tooth sensitivity compared with White Clinic 35% gel INCLUSION CRITERIA: ndividuals of both sexes; over 18 years; in good general and oral health; absence of carious lesions, extensive restorations, fractures, and endodontic treatment in the si Xmaxillary anterior teeth; maxillary canines with an initial shade of A2 or darker, as assessed using the value‐oriented