This randomized, single-blind, placebo-controlled clinical trial aims to evaluate the effect of an experimental gel based on Acmella oleracea (jambú) extract, associated or not with fluoride, in reducing dentin hypersensitivity (DH) in non-carious cervical lesions. The volunteers were randomized into 4 groups according to the treatments applied: CT (control), NP (potassium nitrate), AO (Acmella oleracea) and AF (Acmella oleracea associated with fluoride). Prophylaxis with pumice stone and water was performed on the previously selected teeth and, subsequently, the gels were applied to the cervical region with a microbrush, rubbed for 10 seconds, and remained on the tooth surface for 10 minutes. Three gel application sessions were performed, with 1-week interval between them. The DH evaluation was performed at four time points: baseline (before the first session), T1 (before the second session), T2 (before the third session) and T3, one week after the final application of the products.

Initially, all volunteers will undergo prophylaxis with pumice and water and will receive an oral hygiene kit containing a soft-bristled toothbrush, dental floss, and their assigned toothpaste, along with oral hygiene instructions. Relative isolation with cotton rolls will be performed in the region of the sensitive lesions, followed by the application of the gel corresponding to the participant's group (CT, NP, AO, AF). All gels will be applied in the same manner, using a microbrush applicator. After being rubbed for 20 seconds on each tooth, the gel will remain on the tooth surface for 10 minutes. At the end of this period, the gel will be removed using gauze and thoroughly rinsed. Three clinical sessions will be conducted, with one-week intervals between them.

Inclusion Criteria:

• Presence of non-carious cervical lesions with sensitivity and up to 2 mm in depth
• Miller Class I gingival recession
• Lesions located on the buccal surface of the teeth
• Score ≥ 4 on the Visual Analog Scale (VAS) after tactile and evaporative stimuli
• Healthy periodontal condition
• No other conditions that could explain dentin hypersensitivity
• Good general physical health
• No eating disorders or high-acid diets
• Occlusal stability

Exclusion Criteria:

• Presence of restorations in the hypersensitive areas
• Presence of dental caries, pulpitis, or periodontal pockets
• Enamel cracks
• Systemic diseases
• Continuous use of antibiotics, anti-inflammatory drugs, analgesics, or corticosteroids
• Professional desensitizing treatment received within the three months prior to study recruitment
• Pregnancy or breastfeeding Ongoing orthodontic treatment
• Dental prostheses that may interfere with the assessment of hypersensitivity