PHYSIOLOGICAL AND PATHOLOGICAL DARK PIGMENTATION IN ORAL MUCOSA

The presence of melanocytes in the oral epithelium is a well established fact but their physiological functions are not well defined. milline provides protection from environmental stressors such as ultra violet radiation and reactive oxygen and melanocyte function as a stress sensors having capacity to react and to produce variety of micro-inveremental cytokines, and growth factors modulating immune inflammatory and antibacterial responses. There is wide range of normal and pathological variations in melanin pigmentations of the oral mucosa. Oral pigmentation can be physiological or pathological and endogenous and exogenous. Such lesions represent a variety of clinical entities, ranging from physiologic changes to manifestation of systemic illnesses and malignant neoplasms.The color of oral mucose depend upon the epithelial thickness, the keratin status, the vascularity and the density of the underlying fibrous tissue. Dark or black pigmented lesions can be focal, multifocal or diffuse macules. The pigmented lesions including entiteties such as physiological pigmentation, smokers melanosis, melanotic macule, drugs pigmentation, Peutz-Jeghers syndrome, Kaposi`s sarcoma, pigmentation related to heavy-metal ingestion (lead, mercury, bismuth amalgam), endocrinopathic pigmentation, and melanoma malignum.