Evaluation of the association between orofacial pain and dysphagia

Swallowing has a vital function in airway protection and is the next step after mastication. Swallowing impairment, which is known as dysphagia, is frequently accompanied by pain. Previous clinical studies have shown that orofacial pain affects swallowing function. Thus, it was hypothesized that orofacial noxious inputs may modulate swallowing function. Previous studies using anesthetized animals has proposed that the facial skin-nucleus tractus solitarii (NTS), masseter muscle-NTS, lingual muscle-NTS, and lingual muscle-paratrigeminal nucleus-NTS pathways may be involved in the inhibition of swallowing caused by facial, masseter, and lingual pain. Moreover, the activation of gamma-aminobutyric acidergic NTS neurons is involved in the inhibition of the swallowing reflex following trigeminal noxious inputs. This review focused on the recent management of dysphagia, neural mechanisms of swallowing, and relationship between orofacial pain and swallowing function. This and other future studies in this field can provide a better understanding of both normal and impaired swallowing and can help develop a new approach to treat patients with dysphagia and orofacial pain.