Salivary pooling: is it specific to particular regions in oral submucous fibrosis?

Despite extensive research, the pathophysiology of oral submucous fibrosis (OSMF), a premalignant condition that primarily affects the mucosa, is still unclear, although the chewing of areca nut is known to be the primary cause. While a clear association exists between areca nut and OSMF, very little has been published on the reason for its sporadic incidence in the mouth. Many authors have suggested the site where quid is habitually placed, but this fails to explain multiple sites in those who chew on one side. We hypothesised that the pattern of salivary pooling might affect the distribution of OSMF by carrying the chemicals responsible for mucosal damage. In our study of 174 patients, we evaluated the sites where quid was habitually placed and the areas of salivary pooling, and their association with the incidence of OSMF. Most chewers (136/174, 78%) placed the quid in the buccal vestibule, although other sites were also used including the vestibule of the lip, tongue, and floor of the mouth. The standardised residuals suggested significant associations (p<0.001) between salivary pooling and OSMF, and indicated that salivary pooling affects the mucosal surfaces where it occurs. Our results show that the quid is not the only cause of OSMF. Salivary pooling also has an important role and provides a possible mechanism for the sporadic incidence of the condition. To our knowledge this is the first study to evaluate salivary pooling as a contributory factor in OSMF, and it may help to explain the pattern of distribution. Further work is needed in this area to understand the association more fully.