Evaluation of the Efficacy of Topical Application of Liquid Nitrogen and Ascorbic Acid in Treatment of Gingival Pigmentation

Aim of study The present study will be designed to evaluate the clinical and histomorphometric outcomes of using topical liquid nitrogen and topical ascorbic acid in gingival depigmentation. Primary outcome: • Clinical severity and extension of gingival pigmentation. Secondary outcome: • Histologic assessment of the melanin forming cells.

Inclusion Criteria: * Individuals with mild-to-severe anterior melanin gingival pigmentation in the anterior portion of the upper and lower gingiva according to Dummet's classification will be involved. * The patients included in this study will be Type 1 individuals according to American Society of Anesthesiology . * The age of the patients ranges between 18 and 40 years. Exclusion Criteria: * smoker patients * pregnant and lactating women * patients with any systemic disease that may induce the production of melanin * patients with periodontal disease, non vital anterior teeth * patients with known hypersensitivity to ascorbic acid * patients who had previous depigmentation procedures.