Bell’s Palsy was first described in 1821, and the pathogenesis remains unclear. About 25 percent of cases are related to trauma, surgery, local infection, tumour and stroke. The remainder are now considered viral and associated with ischemia and compression of the facial nerve in the area of the temporal bone.
Herpes simplex virus type 1 (HSV-1) has been identified in some Bell’s Palsy cases. One patient, who developed typical symptoms of Bells Palsy simultaneously with an acute dental infection in the second and third molar area, had the following symptoms:
- Unilateral lack of forehead wrinkles
- Inability to lift the eyebrow
- Inability to close the eye
- Depressed nasolabial fold
- Inability to move the left corner of the mouth and smile
- Inability to purse the lips
Theories to explain the coincidence of Bell’s Palsy occurring at the same time as a dental infection include local compression theory, immune compromise theory and Bell’s Palsy pro-dromal theory. A neurologist can prescribe steroids and antiviral agents plus a tapering course of prednisone. The outcome of facial paralysis depends on the amount ofnerve damage. About 80 percent of patients have completed recovery, 15 percent have partial improvement and five percent have severe residual symptoms and permanent nerve damage. A better understanding of how the seventh cranial nerve is related to dental disease may come from further study of Bell’s Palsy cases.