Introduction Several genetic, metabolic, endocrine, infective, inflammatory, and neoplastic processes and chemical exposure contribute to the development of oral pigmentation. 1 The excessive deposition of melanin in the oral cavity without systemic disease is described as hyperpigmentation, or physiologic pigmentation. 2-4 It is recognized as the localized or diffuse darkening of the oral mucosa, predominately in dark-skinned people. 1,5 While physiologic pigmentation most commonly occurs in the gingiva, it can affect other oral sites like the tongue, buccal mucosa, labial mucosa, and palate. 5,6 The intensity, color (deep purple, brown, or black), and pattern (irregularly shaped striae or strands) of the pigmentation vary. 3,5,7 Physiologic pigmentation is a normal variant and not a disease. Still, it can be an aesthetic problem for people with gummy smiles. 2 Interestingly, although individuals of different ethnicities have the same number of melanocytes, differences in melanin expression determine the color of mucosae. 8,9 As such, differences in the size and distribution of melanosomes, types of melanin, and the masking effect of the overlying epithelium all contribute to variable pigmentation. 5 Physiologic pigmentation is, however, invariably associated with increased deposition of melanin. 5,9 Melanosomes accumulate melanin and transport it to the dendritic-like projections of melanocytes and then to adjacent keratinocytes in the keratinocyte-melanin unit, thus producing pigmentation. 10,11 At least 11 different genes affecting melanin deposition have been implicated in physiologic pigmentation, including those of the encoding adrenocorticotropic hormone and alpha- melanocyte-stimulating hormone, which stimulate the activity of tyrosinase and enhance melanogenesis. 9 Physiologic oral pigmentation is common in some geographic regions and may be related to skin color. A study of 1275 patients attending dental clinics in Jordan reported physiologic oral pigmentation in nearly forty percent of patients, 11 and an Indian study reported a significant correlation between the severity of gingival Prevalence and pattern of physiologic oral pigmentation in a Pakistani population Soulafa Almazrooa 1* ID , Amna Arooj 2 ID , Sobia Hassan 3 ID , Amber Kiyani 4 ID 1 Oral Diagnostic Sciences Department, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia 2 Islamic International Dental College, Riphah International University, Islamabad, Pakistan 3 Periodontology Department, Islamic International Dental College, Riphah International University, Islamabad, Pakistan 4 Oral Medicine Department, Islamic International Dental College, Riphah International University, Islamabad, Pakistan *Corresponding Author: Soulafa Almazrooa, Email: salmazrooa@kau.edu.sa https://johoe.kmu.ac.ir 10.34172/johoe.2403.1627 JOHOE. 2025;14:2403.1627 Original Article © 2025 The Author(s); Published by Kerman University of Medical Sciences. This is an open-access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Journal of Oral Health and Oral Epidemiology Received: March 4, 2024, Revised: February 9, 2025, Accepted: March 10, 2025, ePublished: March 26, 2025 Citation: Almazrooa S, Arooj A, Hassan S, Kiyani A. Prevalence and pattern of physiologic oral pigmentation in a Pakistani population. J Oral Health Oral Epidemiol. 2025;14:2403.1627. doi:10.34172/johoe.2403.1627 Abstract Background: Excessive melanin deposition in the oral cavity without any systemic disease or other known cause is known as hyperpigmentation or physiologic pigmentation. The site and intensity of pigmentation of the oral mucosa varies in different populations, and it is especially common in individuals with darker skin tones. This study aimed to determine the prevalence of physiologic oral pigmentation in a Pakistani population and its association with age, sex, and skin tone. Methods: This was a cross-sectional observational study of 386 consenting individuals aged between 18 and 75 years attending a dental college over two months. Individuals with pathologic pigmentation were excluded based on their history and clinical examination. All participants underwent a comprehensive oral examination to document the sites and intensity of pigmentation, and skin tone was classified according to the Fitzpatrick phototype classifications III, IV, and V. The chi-squared test or Fisher’s exact test was used in the analysis. Results: Nearly sixty percent of the population had some pigmentation within the oral cavity. The most common site of pigmentation was the attached gingiva. Oral pigmentation was significantly associated with darker skin tone and older age but not sex. Conclusion: Oral pigmentation is present in about sixty percent of the Pakistani population and is associated with darker skin tones. Keywords: Gingiva, Hyperpigmentation, Skin pigmentation, Pigmentation, Melanin