To characterize the relationship between bruxism and dystonia, 79 patients (28 men and 51 women) with cranial-cervical dystonia were studied. Sixty-two patients (78.5%), 22 men and 40 women, had bruxism. The mean age at onset of dystonia in patients with bruxism was 52.4 +/- 12.6 years (range 14-80), similar to patients with cranial-cervical dystonia without bruxism. Involuntary oromandibular movements (46 patients) and blepharospasm (34 patients) were the most common initial symptoms among patients with dystonia. About one-fourth of bruxism patients had associated dental problems including TMD (21%) and tooth wear (5%). A majority (58%) of the bruxism patients had diurnal bruxism and 12% had nocturnal bruxism. The bruxism patients were compared to 100 patients with Parkinson's disease (PD), cervical dystonia, cranial dystonia, and normal controls, respectively. The prevalence of bruxism was much higher in the cranial-cervical dystonia patients when compared to normal controls (P < 0.001); however, this difference was not significant between other diseased groups and controls. Medications and botulinum toxin injections, used in the treatment of focal dystonia also provided effective relief of bruxism.