Temporomandibular disorders and painful comorbidities: clinical association and underlying mechanisms.
The association between temporomandibular disorders (TMDs) and headaches, cervical spine dysfunction, and fibromyalgia is not artefactual. The aim of this review is to describe the comorbid relationship between TMD and these three major painful conditions and to discuss the clinical implications and the underlying pain mechanisms involved in these relationships. Common neuronal pathways and central sensitization processes are acknowledged as the main factors for the association between TMD and primary headaches, although the establishment of cause-effect mechanisms requires further clarification and characterization. The biomechanical aspects are not the main factors involved in the comorbid relationship between TMD and cervical spine dysfunction, which can be better explained by the neuronal convergence of the trigeminal and cervical spine sensory pathways as well as by central sensitization processes. The association between TMD and fibromyalgia also has supporting evidence in the literature, and the proposed main mechanism underlying this relationship is the impairment of the descending pain inhibitory system. In this particular scenario, a cause-effect relationship is more likely to occur in one direction, that is, fibromyalgia as a risk factor for TMD. Therefore, clinical awareness of the association between TMD and painful comorbidities and the support of multidisciplinary approaches are required to recognize these related conditions.
Section of Head and Face Physiology, Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, Brazil; Bauru Orofacial Pain Group, University of São Paulo, Bauru, Brazil. Electronic address: Yurimartinscosta@yahoo.com.br.
Yuri Martins
YM
Costa
Bauru Orofacial Pain Group, University of São Paulo, Bauru, Brazil; Department of Prosthodontics, Bauru School of Dentistry, University of São Paulo, Bauru, Brazil.
Paulo César Rodrigues
PC
Conti
Section of Head and Face Physiology, Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, Brazil.
Flavio Augusto Cardoso
FA
de Faria
Section of Head and Face Physiology, Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, Brazil; Bauru Orofacial Pain Group, University of São Paulo, Bauru, Brazil.
Leonardo Rigoldi
LR
Bonjardim
D002574:Cervical Vertebrae; D015897:Comorbidity; D005356:Fibromyalgia / Q000150:complications*; D006261:Headache / Q000150:complications*; D006801:Humans; D059408:Pain Management; D012307:Risk Factors; D013122:Spinal Diseases / Q000150:complications*; D013705:Temporomandibular Joint Disorders / Q000150:complications*