Oromandibular dystonia unresponsive to botulinum toxin: two illustrative cases of condylar dislocation as a structural mimic.

Botulinum toxin therapy is a mainstay treatment for oromandibular dystonia (OMD), but lack of response should prompt reconsideration of both the injection strategy and the underlying diagnosis. Long-standing condylar dislocation is a structural disorder that can mimic OMD by producing mandibular deviation, impaired mandibular closure, dysarthria, dysphagia, and abnormal jaw or tongue movements. We present two illustrative cases in which patients initially diagnosed with OMD underwent botulinum toxin injections into the masseter muscles without meaningful benefit. Subsequent dental and oral/maxillofacial evaluation, including panoramic radiography, revealed long-standing condylar dislocation as the primary diagnosis. Both patients improved after structural correction and prosthetic rehabilitation. These cases do not establish masseter injection failure as diagnostic evidence against OMD; rather, they highlight botulinum toxin non-response as a practical clinical trigger for systematic reassessment in selected patients with suspected OMD. In patients with fixed mandibular deviation, persistent occlusal disturbance, impaired closure, facial asymmetry, or atypical dystonic features, structural reassessment with dental imaging and oral/maxillofacial consultation should be considered before continuing chemodenervation.