The pathogenesis of OSMF has multifactorial etiology including nutritional deficiencies, ingestion of chillies, habit of chewing areca nut, factors like pollution and genetic and immunologic processes.
1. Chewing of Areca nut (betel nut):
The major component of betel quid is areca nut, tobacco, lime and piper leaf. Betel nut is a major etiologic agent in OSMF. Betel nut consists of arecoline, an active alkaloid which stimulates fibroblast to increase production of collagen by 150%and also upregulates COX-2 expression. It causes increased collagen production leading to fibrosis. Areca nut quid contains cytotoxic & genotoxic agents which leads to arecoline cytotoxicity and stimulates self-proliferation and thiol- depletion . Earlier studies have reported that, OSMF remains active even after termination of the chewing habit signifying that components of areca nut initiate OSMF. Gene expression in the fibroblasts is affected by areca nut, due to which greater amount of normal collagen is produced in OSMF.. Trivedy C et al. conducted a study and concluded that there is increased level of copper in saliva after placing a areca nut quid in mouth for 5- 10 min. Copper stimulates fibrogenesis through up -regulation of lysyl oxidase activity by working as an initiating factor in OSMF .