Is a neuropathic mechanism involved in the perception of oral dryness?

The aim of the present study was to review the existing phenomena which could affect subjective oral dryness and to consider the possibility that neural processing is involved in the perception of oral dryness.

A comprehensive review of scientific literatures relevant to contributing factors of dry mouth symptoms including salivary parameters related with oral dryness and role of neural mechanisms in perception of dry mouth symptoms was conducted.

Several previous reports suggested the possibility of neural processing mechanisms in perception of oral dryness. The decreased pain threshold in the oral cavity of rats with dry tongue and complaints of subjective oral dryness in patients with burning mouth syndrome, of which lacked an actual decrease in salivary output and mucosal wetness, could support this idea. Sensory changes in the oral mucosa and oral dryness may have a bi-directional influence that patients with oral dryness would be more subject to neuropathic pain in the oral mucosa, and those with neuropathic pain in the oral cavity could have complaints associated with higher levels of dry mouth symptoms.

A bi-directional influence between sensory change in the oral mucosa and subjective oral dryness could be assumed. We suggest the administration of neuropathic pain medications for controlling subjective oral dryness in patients without objective sign of hyposalivation.