Study setting and patient selection
hypersensitivity
PERIODONTAL DISEASE, HYPERSENSITIVITY
Patients were recruited from the outpatient clinic of the Department of Oral Medicine, Periodontology, Oral Diagnosis and Oral Radiology, Faculty of Dentistry, Alexandria University. After conducting an initial assessment that included reviewing medical and dental histories and performing clinical examinations to determine subject eligibility, 26 subjects met the following inclusion criteria: adults of either sex between 18 and 40 years old with physiologic melanin pigmentation in the anterior esthetic zone of the maxillary or mandibular gingiva, and who were free from any systemic diseases or conditions.On the other hand, the exclusion criteria included: smokers, pregnant and lactating women, drugs intake which associate with gingival melanin pigmentation such as antimalarials drugs, phenothiazines and oral contraceptives, patients with periodontal disease, and patients with known hypersensitivity to ascorbic acid.