Oral appliances in the treatment of oromandibular dystonia: a systematic review.

Oromandibular dystonia (OMD) is a clinically and etiologically heterogeneous form of focal dystonia with variable social and functional implications. The results of pharmacological treatment and botulinum toxin infiltrations are often unsatisfactory. We performed a systematic review on the effects of oral and dental appliances in patients with OMD. Most of the reports in the literature are single subject descriptions or small case series with a considerable variability in the type of dystonia, the type of evaluated appliances and in the outcome measures. Only one report included a large group of unselected patients that were evaluated with a mixture of outcome measures. Although it appears that a number of OMD patients, especially those who benefit from sensory tricks, may sustain some improvement with the use of oral appliances, no definitive conclusions can be drawn about the type of patients that may benefit, nor about the preferred type or mode of appliance. More research in this field is needed, using standardized approaches and clearly defined outcome measures in larger cohorts of OMD patients that are clinically and diagnostically well characterized.