Further on the causation of oral submucous fibrosis.

Oral submucous fibrosis is perhaps a disease of multifactorial aetiology, of which areca nut usage is definitely a causative factor. We disagree with the previous reports in that the action of areca quid on the oral mucosa is not that simplistic and is not dictated solely by the duration of exposure to it or by simple process of passive diffusion. We noted that the role of copper cannot be segregated from that of zinc, the biochemical relatedness of these two elements is well elucidated. The transport of copper in to the oral epithelium may be dictated more by the composition of the quid rather than the time of exposure. Zinc is implicated in the modulation of mucosal metallothionein, thereby interfering with copper absorption. The bioavailability of zinc in its turn depends on elements like calcium and iron present in oral fluid. The usage of slaked lime(calcium hydroxide) as as ingredient of betel quid, thereby causing an interference with zinc bioavailability is a matter of concern. Of practical importance is the processing of raw areca nut and the various proprietary forms (sachets) available in the market, the toxic effects of which varies depending on its contents. Studies on the role of geochemical factors in modulating the chemical composition of the various nut forms, thereby altering its toxic effects will be an interesting pursuit.