Comorbidity between fibromyalgia and temporomandibular disorders: a systematic review

Objective. Fibromyalgia (FM) is characterized by bodywide diffuse and chronic musculoskeletal pain, which, in some patients, can include pain in the masticatory muscles and temporomandibular joints; those patients are defined as having temporomandibular disorders (TMDs). The purpose of this systematic review is to study the association between FM and TMD, as well as the prevalence and characteristics of TMD in patients with FM or the features and prevalence of FM in patients with TMD. Study Design. Our bibliographic search was conducted from January 1, 2005, to May 31, 2018, in the MEDLINE database by using its free search engine PubMed and the keywords "fibromyalgia," "temporomandibular joint disorder," and "orofacial pain." Results. Of the 185 studies found in this search, only 19 met the inclusion criteria. These studies showed a high prevalence of TMD in patients with FM. Muscle pain, temporomandibular joint pain, and muscle tenderness on palpation are the most common symptoms. These results suggest an association between TMD and FM; FM can be an etiologic or aggravating factor for TMD, or it may represent a general vulnerability to pain disorders. Besides, the 2 pathologies may share some regional or central mechanisms in common. Conclusions. The high prevalence of TMD in patients with FM emphasizes the need to consider the signs and symptoms of TMD in the diagnosis of FM to improve pain management in these patients.