Fourteen patients suffering from primary muscular disease (myopathies), including seven with Duchenne's muscular dystrophy, were compared to 11 patients whose neuromuscular disorders were of neuropathic origin. Mesioclusion was observed only in the group with Duchenne's muscular dystrophy. Posterior crossbite, anterior open bite, mouth breathing, and large tongue were also more prevalent in the group with myopathies, especially the Duchenne's patients, than they were in the group with neurogenic disorders. The Duchenn'es patients exhibited a statistically significant delay in dental emergence, unlike the patients with other myopathies and those with neurogenic disorders. Dentition and occlusion may be more affected in patients with myopathies, especially Duchenne's muscular dystrophy, than they are in patients with neurogenic disorders.