Chronic Temporomandibular Disorders Are Not Necessarily Associated with a Compromised Endogenous Analgesic System

Abstract

Aims Our previous work demonstrated that women with temporomandibular disorder (TMD) exhibit enhanced temporal summation of pain upon repetitive mechanical stimulation of the fingers, compared to healthy controls, suggestive of widespread up regulated central nociceptive processing in this patient population. The current study asks whether TMD case-control differences in Conditioned Pain Modulation (CPM) exist, using a mechanically evoked Temporal Summation (TS) model. Methods A series of 10 repetitive, mildly noxious, mechanical stimuli were applied to the fingers of 30 TMD women and 30 age-matched healthy women. The subjects rated the pain intensity caused by the 1st, 5th and 10th stimulus in the train. To evaluate CPM, the same series of mechanical stimulations were applied with concomitant exposure of the other hand to a painfully cold water bath. Results Pain ratings increased significantly with stimulus repetition (p<0.01) and CPM significantly reduced TS of pain (p<0.01). Of particular note, both groups showed very similar degrees of CPM, with no significant group difference. Conclusion Painful TMD is not necessarily associated with a compromised ability to engage the endogenous analgesic system in an experimental setting.

Evidence for Central Sensitization in Patients with Temporomandibular Disorders: A Systematic Review and Meta‐analysis of Observational Studies

“…The study search strategy is presented in the form of a flow chart (Figure ). Twenty‐two articles (11 case‐control studies and 11 cross‐sectional studies) met the inclusion criteria, of which 8 were included in the meta‐analysis (5 cross‐sectional and 3 case‐control studies). Descriptive characteristics of the studies included in this study are presented in Table .…”

“…All patients in the studies had experienced pain in the TMJ area for at least 3 months. As for the pain characteristics in the experimental group #bib11 studies included data about myofascial pain, 4 of the studies included mixed pain (myogenous and arthrogenous), and 1 study referred only to arthrogenous pain . In addition #bib4 studies referred to nonspecific orofacial pain, and 2 studies did not describe the characteristics of pain .…”

“…Five of the case‐control studies were scored as good quality, while 6 studies were scored as fair quality and 1 received a poor quality score …”

Role of endogenous pain modulation in chronic pain mechanisms and treatment

“…Temporomandibular disorder has also been explored in this regard. King et al 37 reported less efficient CPM in these patients; Garrett et al 24 reported CPM similar to healthy controls, whereas Kothari et al 42 reported reduced CPM in TMDs after surgery. Oono et al 69 reported reduced CPM in TMD, but only when measured from affected sites.…”

Hypoalgesia After Exercise and the Cold Pressor Test is Reduced in Chronic Musculoskeletal Pain Patients With High Pain Sensitivity

“…This finding is in agreement with a study by Staud et al 59 on patients with chronic widespread pain, but in contrast to a previous study that showed reduced TS during the cold pressor test in patients with temporomandibular disorder. 60 Different pain conditions, assessment time points, and assessment sites may explain the equivocal results. Moreover, in healthy participants, paradigms of CPM have been shown to reduce temporal summation of pain, 61 highlighting potential differences in the effect of the CPT on central pain mechanisms of pain summation between healthy participants and patients with chronic pain.…”