Painful temporomandibular disorders (TMD) and comorbidities in primary care: associations with pain-related disability

Assessment of chronic overlapping pain comorbidities for the management of temporomandibular disorders: Secondary analysis of a randomized clinical trial

BACKGROUND

Chronic painful temporomandibular disorders (TMD) are a functional pain syndrome that embodies a spectrum of clinical manifestations and expresses great complexity through the coexistence of multiple comorbidities.

OBJECTIVE

Evaluate the prevalence of pain comorbidities, explore the correlation between comorbidities, kinesiophobia, catastrophizing, and pain disability at baseline, and determine variables of interest for prediction response to physiotherapy interventions at different follow-up times.

METHODS

This is a secondary analysis of a previously conducted randomized controlled trial (RCT). Outcomes and covariables for this secondary analysis were collected from subjects with chronic TMD (≥3 months), based on the DC/TMD diagnostic criteria, assigned to a multimodal treatment and a second manual therapy control group. The participants underwent follow-up assessment at 7 and 19 weeks. The outcomes (dependent variables) for these analyses were craniofacial pain disability, catastrophizing, and kinesiophobia. However, these outcomes were also used as covariables of interest in addition to comorbidity prevalence and severity at baseline for different analyses. We performed linear regression analyses to determine the association between our outcomes and covariables at baseline and at different follow-ups.

RESULTS

Comorbidity severity explained craniofacial pain disability at baseline, showing a strong correlation (Standardized B: 0.40, p-value: 0.017). Higher comorbidity severity, led to higher craniofacial pain score. Comorbidity severity and baseline catastrophizing predicted a better response to treatment for craniofacial pain improvements at short and long term (R2 .22, p-value : 0.009 and R2 .19, p-value: 0.02 respectively).

CONCLUSION

This study provides insight into the prevention and clinical management of chronic pain related to TMD.

The role of pain-related disability on treatment outcome and psychosocial symptoms in patients with temporomandibular disorders - a pilot study

OBJECTIVE

The aim of the pilot study was to investigate the association of pain-related disability with the outcome of conservative treatment of temporomandibular disorders (TMD) and with depressive and non-specific physical symptoms among TMD pain patients utilizing Graded Chronic Pain Scale 1.0 (GCPS1.0) as a screening instrument.

MATERIAL AND METHODS

The study included 80 adult patients who were referred to the Oral and Maxillofacial Department, Oulu University Hospital, Finland, due to TMD pain. At baseline, pain-related disability was assessed by using the GCPS1.0 according to the Research Diagnostic Criteria for TMD (RDC/TMD), and the patients were categorized into three TMD subtypes, 1-3. Patients were given conservative TMD treatment. At follow-up visits (1, 3, 6, and 12 months), patients evaluated the pain intensity on an NRS and described the treatment outcome and the severity of the TMD symptoms on a numerical scale.

RESULTS AND CONCLUSIONS

Patients with TMD subtype 3 (moderate/severe disability) had the highest NRS scores and described their symptoms as most severe at each time point, statistically significantly so at 1-month and 6-month follow-up (p < .05). The highest proportion of depressive symptoms was found in TMD subtype 3 (p < .05). The current pilot study showed that moderate/severe TMD-related disability, based on the GCPS 1.0 as a screening tool, may be linked with poor treatment outcome and depressive symptoms. Studies with larger samples are needed to confirm the results.

Spinal CCK1 Receptors Contribute to Somatic Pain Hypersensitivity Induced by Malocclusion via a Reciprocal Neuron-Glial Signaling Cascade

Recent studies have shown that the incidence of chronic primary pain including temporomandibular disorders (TMD) and fibromyalgia syndrome (FMS) often exhibit comorbidities. We recently reported that central sensitization and descending facilitation system contributed to the development of somatic pain hypersensitivity induced by orofacial inflammation combined with stress. The purpose of this study was to explore whether TMD caused by unilateral anterior crossbite (UAC) can induce somatic pain hypersensitivity, and whether the cholecystokinin (CCK) receptor-mediated descending facilitation system promotes hypersensitivity through neuron-glia cell signaling cascade. UAC evoked thermal and mechanical pain hypersensitivity of the hind paws from day 5 to 70 that peaked at week 4 post UAC. The expression levels of CCK1 receptors, interleukin-18 (IL-18) and IL-18 receptors (IL-18R) were significantly up-regulated in the L4 to L5 spinal dorsal horn at 4 weeks post UAC. Intrathecal injection of CCK1 and IL-18 receptor antagonists blocked somatic pain hypersensitivity. IL-18 mainly co-localized with microglia, while IL-18R mainly co-localized with astrocytes and to a lesser extent with neurons. These findings indicate that the signaling transduction between neurons and glia at the spinal cord level contributes to the descending pain facilitation through CCK1 receptors during the development of the comorbidity of TMD and FMS. PERSPECTIVE: CCK1 receptor-dependent descending facilitation may mediate central mechanisms underlying the development of widespread somatic pain via a reciprocal neuron-glial signaling cascade, providing novel therapeutic targets for the clinical treatment of TMD and FMS comorbidities.

Back and neck pain: A comparison between acute and chronic pain-related Temporomandibular Disorders

Background

Temporomandibular disorders (TMDs) are common and cause persistent pain. Comorbidities are associated with TMDs and can affect the effectiveness of their treatments. The literature is lacking enough evidence on the difference between acute and chronic pain, particularly in TMDs. Investigating this difference could highlight potential risk factors for the transition from acute to chronic pain-related TMDs.

Aim

To compare the likelihood of back and neck pain (BP, NP) between acute and chronic pain-related TMDs (AP-TMD, CP-TMD) as defined by pain duration and pain-related disability.‎.

Methods

Participants with AP-TMDs (≤3 months) and CP-TMDs (>3 months) were recruited according to the diagnostic criteria and research diagnostic criteria of TMD. BP and NP were assessed using a self-reported checklist. CP-TMDs defined by disability (chronic disability) and depression and anxiety symptoms were assessed using validated instruments. Logistic regression analyses were employed.

Results

This study enrolled 487 adults with AP-TMD (n = 118) and CP-TMD (n = 369). Relative to AP-TMD, participants with CP-TMD had twice the odds of reporting NP (odds ratio [OR] = 2.17‎, 95% CI 1.27-3.71) but not BP ‎‎(OR = 0.96, 95% CI 0.57-1.64). Participants with chronic disability were twice as likely to report NP ‎(OR = 1.95‎, 95% CI 1.20-3.17‎) but not BP (OR = 1.13, 95% CI 0.69-1.82)‎ compared to those without. All analyses were adjusted for age, sex, and anxiety and depression symptoms.

Conclusions

Within the limitations of this study, results suggest that central dysregulation or trigeminocervical convergence mechanisms are implicated in the process of pain-related TMD chronification and highlight the relevance of considering disability when defining CP-TMDs.

Nonpharmacological Interventions for Pain in Patients with Temporomandibular Joint Disorders: A Systematic Review

This systematic review aimed to compare the efficacy of nonpharmacological therapies for painful temporomandibular joint disorders. The protocol was registered on International Prospective Register of Systematic Reviews (PROSPERO) database (CRD42020171364). The search was performed on the electronic databases PubMed, Google Scholar, Clinical Trials, and Web of Science. The eligibility criteria were randomized controlled trials in patients diagnosed with painful temporomandibular joint disorders comparing the pain relief between conventional treatment and nonpharmacological therapies such as acupuncture, physiotherapy, low-level laser, and massage. Fourteen articles were included in this review. At the overall bias of the studies included, 71.42% exhibited some concerns and 28.57% had high risk. The efficacy of nonpharmacological interventions was found to be moderate in the short term and variable in the long term for pain reduction in patients with temporomandibular joint disorders. The evidence pointed out that acupuncture, laser therapy, and physiotherapy are potentially useful interventions for pain relief in patients with temporomandibular joint disorders. However, there is a lack of consistency and short-term follow-up in the studies to determine the lasting of such effect.

Ultrasound is Effective to Treat Temporomandibular Joint Disorder

Background

Temporomandibular joint disorder (TMD) affects millions of people. It is unclear if low intensity ultrasound (US) is effective to treat TMD.

Methods

A total of 160 patients with TMD were enrolled in this study. The subjects were randomized into two groups to receive US therapy or no therapy. Patients in the US group were given US therapy once a day for 5 days per week for 2 consecutive weeks. Before and 4 weeks and 6 months after the treatments, the patients were assessed for pain using visual analog scale (VAS) and the maximum pain-free inter-incisal distance (IID). In addition, mandibular movement (MM), jaw noise (JN), disability index (DI) and craniomandibular index (CMI) were also assessed.

Results

Compared with the patients before the therapy, VAS, IID, MM, JN, DI and CMI in the US group were significantly improved 4 weeks and 6 months after therapy. However, 6 months after the therapy, US group had a recurrence rate of 2.63%.

Conclusion

US therapy can significantly reduce the pain, and improve the functionality of the temporomandibular joint and mouth opening limit for TMD patients, and is therefore recommended for TMD patients.

Craniocervical and Cervical Spine Features of Patients with Temporomandibular Disorders: A Systematic Review and Meta-Analysis of Observational Studies

To assess neck disability with respect to jaw disability, craniocervical position, cervical alignment, and sensorimotor impairments in patients with temporomandibular disorders (TMD), a systematic review and meta-analysis of observational studies trials were conducted. The meta-analysis showed statistically significant differences in the association between neck disability and jaw disability (standardized mean difference (SMD), 0.72 (0.56-0.82)). However, results showed no significant differences for cervical alignment (SMD, 0.02 (-0.31-0.36)) or for the craniocervical position (SMD, -0.09 (-0.27-0.09)). There was moderate evidence for lower pressure pain thresholds (PPT) and for limited cervical range of motion (ROM). There was limited evidence for equal values for maximal strength between the patients with TMD and controls. There was also limited evidence for reduced cervical endurance and conflicting evidence for abnormal electromyographic (EMG) activity and motor control in TMD patients. Results showed a clinically relevant association between cervical and mandibular disability in patients with TMD. Regarding sensory-motor alterations, the most conclusive findings were observed in the reduction of PPT and cervical ROM, with moderate evidence of their presence in the patients with TMD. Lastly, the evidence on impaired motor control and cervical EMG activity in patients with TMD was conflicting.

The impact of chronic orofacial pain on health-related quality of life

Background and aims

Health-related quality of life (HRQoL) assessments have been widely used in pain medicine as they are able to reflect the subjective and multidimensional nature of chronic pain. Studies have shown a consistent impairment in HRQoL in different chronic pain conditions. However, it is not known whether HRQoL is impaired in chronic orofacial pain (OFP). The generic 15D HRQoL instrument has been shown to fare as well as or better than other generic HRQoL instruments in the study of chronic pain. The aim was to investigate HRQoL in patients with chronic OFP using the generic 15D HRQoL instrument. The validity of the instrument was tested by studying the association of the 15D data with pain interference.

Methods

One hundred fifty-one patients (mean age 50 years, SD 15 years, 119 females) were recruited from three tertiary facial pain clinics. HRQoL data of the participants were contrasted with that of an age- and gender- standardized sample of general population by comparing the mean 15D scores and profiles. The data for the general population came from the National Health 2011 Survey representing Finnish population aged 18 years and older. Pain interference was assessed using Brief Pain Inventory. Based on pain interference distribution the participants were divided into tertiles. Statistical comparison between patient and population HRQoL values were performed using Monte-Carlo-type simulations. Statistical significance for the hypothesis of linearity was evaluated by using generalized linear models.

Results

The mean 15D score of OFP patients (0.824, SD 0.113) was statistically significantly lower than that of the age- and gender-standardized general population (0.929, SD 0.019) (p < 0.001). The difference between the patients and the general population was also clinically important, i.e. over the minimum clinically important difference in the 15D score. All mean 15D dimension values were significantly lower compared with the general population values (p < 0.001 for all dimensions). The largest differences were seen in the dimensions of discomfort and symptoms (0.418, SD 0.222 vs. 0.816, SD 0.027), sleeping (0.693, SD 0.258 vs. 0.838, SD 0.029), and vitality (0.702, SD 0.221 vs. 0.884 SD 0.026). There was a statistically significant linear decrease in the 15D dimension values (p < 0.001) with increasing pain interference. The greatest differences were found on the dimensions of discomfort and symptoms, sleeping and vitality.

Conclusions

HRQoL is significantly impaired in patients with chronic OFP. A decrease in the 15D dimension values with increasing pain interference indicated convergent validity between 15D and pain interference.

Implications

The findings suggest that 15D is an appropriate instrument for use in the assessment of HRQoL in OFP patients. By showing the usefulness of the 15D, the present study may encourage further use of generic HRQoL assessments in the study of chronic OFP, and contribute e.g. to the implementation of HRQoL as one of the core outcome measures in future treatment studies on chronic OFP.