TMD and chronic pain: A current view

Abstract

This review aims at presenting a current view on the physiopathologic mechanisms associated with temporomandibular disorders (TMDs). While joint pain is characterized by a well-defined inflammatory process mediated by tumor necrosis factor-α and interleukin, chronic muscle pain presents with enigmatic physiopathologic mechanisms, being considered a functional pain syndrome similar to fibromyalgia, irritable bowel syndrome, interstitial cystitis and chronic fatigue syndrome. Central sensitization is the common factor unifying these conditions, and may be influenced by the autonomic nervous system and genetic polymorphisms. Thus, TMDs symptoms should be understood as a complex response which might get worse or improve depending on an individual's adaptation.

Evaluation of body painful areas in patients with muscular temporomandibular disorder: a retrospective study

“…A possible reason for the coexistence of TMD and cervical pain is based on the neurophysiologic conversion and sensitization principle. A constant nociceptive input in second order neurons may increase neuronal sensitivity and, with this, non-nociceptive impulses of other areas within the same segment converging to such neurons may increase the nociceptive sensation, that is, frequent impulses coming from the upper region of the trapezium may increase trigeminal spinal nucleus sensitivity and so non-nociceptive stimuli in the masticatory system could lead to painful sensation in the trigeminal region 6 . In these cases, patients have painful sensation in orofacial and cervical regions.…”

“…There is comorbidity when two diseases have correlation and temporal continuity, and may appear simultaneously or one precede the other with more than casual association, and may share common pathophysiological aspects and clinical characteristics 4 , which often leads to diagnostic difficulty in the dental clinic. Trigeminal neuralgia, pulpitis, migraine, tension headache and fibromyalgia 5,[6][7][8][9][10][11][12][13][14][15][16][17][18] are some of the most common TMD-related comorbidities. TMD is considered a chronic disease, being muscular TMD a functional pain syndrome with characteristics similar to cervical pain, fibromyalgia, interstitial cystitis, irritable bowel syndrome and chronic fatigue syndrome 3,5,8 .…”

“…Its pathophysiological mechanisms are still being studied 9 and seemingly show changes in sensory processing with increased neuronal membrane excitability, increased substance P levels, NMDA receptors activation, increased brain areas responsible for pain processing and decreased inhibitory influence of dorsal horn neurons on descending pain system, thus facilitating the development of central sensitization 10 and perpetuating pain. Clinical studies have shown that TMD patients may have several comorbidities, such as migraine, fibromyalgia, sleep disorders, anxiety and depression, and myofascial pain in addition to orofacial pain [11][12][13] which may worsen pain and influence the possibility of developing central sensitization 6,14,15 . TMD may also influence the management of other pain presentations.…”

Peripheral and Spinal Mechanisms of Pain and Dry Needling Mediated Analgesia: A Clinical Resource Guide for Health Care Professionals

“…Previous studies have demonstrated increased sensitivity to mechanical stimulation and receptive field expansion in dorsal horn neurons following injection of bradykinen into the lumbar multifidus [69,70]. By recording pain threshold following repeated stimuli to peripheral C-fibers, a number of studies have also reported wind-up related, central sensitization in patients with low back pain [71][72][73] TMJ pain [74] shoulder pain [75] and fibromyalgia [76]. Subacute or chronic C-fiber mediated pain increases the release of glutamate and substance-P from sensory afferents in spine, leading to hypersensitivity of second order, dorsal horn neurons.…”

Estudo dos efeitos do composto GYY-4137, um doador de sulfeto de hidrogênio (H₂S), na sinovite aguda induzida por carragenina na articulação temporomandibular de ratos.

“…A etiologia das DTMs é descrita como multifatorial, com influência de fatores biológicos e psicológicos, tais como lesões traumáticas ou degenerativas da ATM, alterações esqueléticas, alterações na oclusão, fatores emocionais, bruxismo, ausências dentárias, mastigação unilateral, má postura corporal e hábitos parafuncionais (Furquim et al, 2015;Okeson, 2008).…”