This randomized, controlled, blinded clinical trial evaluated the effectiveness of different desensitizing protocols in preventing pulp inflammation after bleaching treatment with 35% hydrogen peroxide (PH) (Whiteness PH 35%).

Thirty healthy third human molars extracted by orthodontic indication were randomized and allocated into five groups (n = 6): CN (negative control): without intervention; CP (Positive control): PH; PMB: PH + photobiomodulation with low power laser; CPP: PH + casein phosphopeptide phosphopeptide amorphous calcium phosphate (CPP-ACPF); NANO: PH + nanohydroxyapatite. The office whitening was performed in two sessions with a single application of 45 min and an interval of 48 hours between them. Pulp tissues were removed for immunohistochemical analysis. Immunostaining was performed for Caspase 3 using an Axio Scope.A1 microscope.

Inclusion criteria:

• Lower third molars class I position A
• Maxillary third molars horizontal position A
• Absence of caries and enamel fracture
• Absence of periodontal disease
• Extraction of third molars for orthodontic reasons
• No allergy to the anesthetic and positive pulp sensitivity test

Exclusion criteria:

• Calcification in the middle third of the root
• Drug users or smokers
• Patients who have already done whitening
• Root apex with incomplete formation and patients with systemic problems that would make surgery impossible