This pilot randomized clinical trial aims to evaluate the effect of adjunctive acid application on the esthetic outcomes of gingival melanin depigmentation. Participants with physiologic gingival hyperpigmentation will be randomly assigned to receive conventional gingival depigmentation with or without adjunctive acid application. The primary outcome is the improvement in gingival esthetics, while secondary outcomes include postoperative healing, pain, patient satisfaction, and recurrence of pigmentation. The findings of this study may help identify whether adjunctive acid application improves the clinical outcomes of gingival depigmentation procedures.

Inclusion Criteria:

• Adults aged 18-50 years.
• Presence of physiologic gingival melanin pigmentation requiring treatment.
• Good general health.
• Good periodontal health or a healthy periodontium after initial periodontal therapy.
• Willingness to participate and provide written informed consent.
• Ability to attend all follow-up visits.

Exclusion Criteria:

• Current smokers or tobacco users.
• Pregnancy or breastfeeding.
• History of systemic diseases that may affect wound healing (e.g., uncontrolled diabetes or immunocompromised conditions).
• Use of medications known to affect gingival pigmentation or wound healing.
• Previous gingival depigmentation treatment in the study area.
• Active periodontal disease or oral infection. Known allergy or hypersensitivity to the study acid or related materials.

Individual participant data will not be shared because informed consent for public data sharing was not obtained, and sharing could compromise participant confidentiality.