Prevalence of Bruxism in Hemifacial-Spasm Patients

A previous study reported an increased prevalence of bruxism (25%) in patients with cranio-cervical dystonia (CCD) compared to normal controls (13%). CCD can affect the muscles of the head and neck. Besides the CCD affecting these muscles, hemifacial spasm (HFS) is a form of peripheral myoclonus due to a neurovascular conflict affecting the muscles of the face. The fact that they affect the same muscle regions could lead to other links in clinical manifestations such as bruxism, which is more common in patients with CCD than in the normal population. The aim was to study the prevalence of bruxism in patients with HFS.

Patients with HFS were enrolled in the department of clinical neurophysiology (Bordeaux University Hospital) over a 6-month period. They were paired regarding age, the absence of neurological pathology or neuroleptics intake. To be included in the study, patients needed to have had unilateral involuntary facial muscle contractions affecting one hemiface. A hetero-questionnaire and a clinicial study were performed. The diagnostic criteria of bruxism included parafunction items such as grinding and clenching and at least one of the following clinical signs: abnormal tooth wear, temporomandibular joint (TMJ) pain, TMJ clicking, muscle hypertonia (masseter or temporal muscles). Additional epidemiological data were collected including age, sex, disease duration, stress, and sleep disorders. Stress symptoms inventory included symptoms like depression, strong heartbeat, dry mouth, anger, inability to concentrate, weakness, fatigability, insomnia, headache, and excessive sweating. The sleep disorder diagnosis included at least two of the symptoms described in the ICSD-3. All these criteria were recorded as either present (scored "1") or absent (scored "0").

The prevalence of bruxism in the two groups (normal and HFS) was not significantly different (p = 0.37). The rate was not significantly different between sleep and awake bruxism (p = 0.15) in both groups. Stress influenced the occurrence of bruxism in these two groups (p < 0.001).

The results of this study indicated that clenching behaviors were higher in the HFS group, and that factors such as stress affected this group. The prevalence of bruxism was not higher in this population than in the normal control.