Temporomandibular dysfunction and headache disorder.

It has been well established that primary headaches (especially migraine, chronic migraine, and tension-type headache) and temporomandibular dysfunction (TMD) are comorbid diseases, with the presence of one of them in a patient increasing the prevalence of the others. The relationship between the 2 diseases may involve the sharing of common physiopathological aspects. Studies about the treatment of this disease association have shown that a simultaneous therapeutic approach to the 2 diseases is more effective than the separate treatment of each. As a consequence, specialists in orofacial pain are now required to know the criteria for the diagnosis of headaches, and headache physicians are required to know the semiologic aspects of orofacial pain. Nevertheless, a headache may be attributed to TMD, instead be an association of 2 problems - TMD and primary headaches - in these cases a secondary headache, described in item 11.7 of the International Classification of Headache Disorders, is still a controversial topic. Attempts to determine the existence of this secondary headache with a specific or suggestive phenotype have been frustrated. The conclusion that can be reached based on the few studies published thus far is that this headache has a preferential unilateral or bilateral temporal location and migraine-like or tension-type headache-like clinical characteristics. In the present review, we will consider the main aspects of the TMD-headache relationship, that is, comorbidity of primary headaches and TMD and clinical aspects of the headaches attributed to TMD from the viewpoint of the International Headache Society and of a group of specialists in orofacial pain. This paper aims to explore our understanding of the association between TMD and headaches in general and migraine in particular.