The prevalence of comorbid chronic pain conditions among patients with temporomandibular disorders: A systematic review

Downregulation of lysine-specific histone demethylase 1A (KDM1A/LSD1) in medial prefrontal cortex facilitates chronic stress-induced pain and emotional dysfunction in female mice

Chronic primary pain, characterized by overlapping symptoms of chronic pain, anxiety, and depression, is strongly associated with stress and is particularly prevalent among females. Recent research has convincingly linked epigenetic modifications in the medial prefrontal cortex (mPFC) to chronic pain and chronic stress. However, our understanding of the role of histone demethylation in the mPFC in chronic stress-induced pain remains limited. In this study, we investigated the function of lysine-specific histone demethylase 1A (KDM1A/LSD1) in the context of chronic overlapping pain comorbid with anxiety and depression in female mice. We employed a chronic variable stress model to induce pain hypersensitivity in the face and hindpaws, as well as anxiety-like and depression-like behaviors, in female mice. Our findings revealed that chronic stress led to a downregulation of KDM1A mRNA and protein expression in the mPFC. Notably, overexpressing KDM1A in the mPFC alleviated the pain hypersensitivity, anxiety-like behaviors, and depression-like behaviors in female mice, without affecting basal pain responses or inducing emotional distress. Conversely, conditional knockout of KDM1A in the mPFC exacerbated pain sensitivity and emotional distress specifically in females. In summary, this study highlights the crucial role of KDM1A in the mPFC in modulating chronic stress-induced overlapping pain, anxiety, and depression in females. Our findings suggest that KDM1A may serve as a potential therapeutic target for treating chronic stress-related overlap pain and associated negative emotional disorders.

Oral habits and temporomandibular joint disorders according to stress levels among military personnel in South Korea: A cross-sectional study

BACKGROUND

Military personnel suffer from stress-induced temporomandibular joint disorders (TMD). No previous studies have evaluated the oral habits and TMD in military personnel based on their stress levels.

OBJECTIVES

To examine the correlation between oral habits and TMD based on stress levels. In addition, we assessed the relationship between stress levels and TMD by military rank as well as the impact of oral habits on TMD.

METHOD

This cross-sectional survey included 89 military personnel who visited the Armed Forces Medical Center in Korea with discomfort in the temporomandibular joint (TMJ) discomfort. Oral habits, stress level, TMD and general characteristics of the subjects were investigated. A questionnaire was distributed to the subjects who agreed to the study, and they were asked to respond in a self-written form. Multiple linear regression analysis was performed to examine the factors that affect oral habits and TMJ symptoms.

RESULTS

Stress scores and oral habits were highest in the 'Private' rank. In contrast, temporomandibular joint symptoms were highest in the 'Corporal' rank. Additionally, the high-risk stress group exhibited higher scores in oral habits and TMD compared to the potential stress group. Furthermore, there was a positive correlation between an increase in high-risk stress scores and a rise in oral habits. And individuals with more oral habits are at an increased likelihood of experiencing TMD.

CONCLUSION

Our study findings suggest that military personnel with prevent TMD and improve oral habits by addressing stress levels.

Conceptualising TMD symptom burden in youths: Symptom duration, frequency, intensity and interference

OBJECTIVE

This study aimed to conceptualise Temporomandibular disorder (TMD) symptom burden and severity and explored their interrelationships with somatic symptoms and psychological distress.

METHODS

Participants were recruited from a local polytechnic. The quintessential five TMD symptoms (5Ts) of the Diagnostic Criteria for TMDs (DC/TMD) were appraised and extended to evaluate the duration, frequency, intensity and interference of discrete TMD symptoms. Global TMD severity (GS) was computed by totaling the points for all TMD symptoms and dimensions. TMD (TS) and somatic symptom (SS) burden were assessed based on the Somatic Symptoms Scale-8, while psychological distress was measured with the Depression, Anxiety and Stress Scales-21. Statistical analyses were performed using Kruskal-Wallis/Dunn tests and Spearman's correlation (α = .05).

RESULT

Of the 366 eligible participants (mean age 19.1 ± 2.3 years), 51.4% were 5Ts-negative and 48.6% were 5Ts-positive. Among the 5Ts-positive individuals, 25.3%/64.0% were 'bothered a little' whereas 4.5%/10.7% were 'bothered a lot' by TMD pain/headache. Correspondingly, 32.6%/12.4%/5.1% were 'bothered a little' while 2.8%/2.8%/1.1% were 'bothered a lot' by TMJ sounds/closed/open locking. TS burden was moderate-to-strongly correlated to aggregate symptom duration, frequency, intensity, interference, GS and SS burden (rs = .50-.88). While TS burden and GS were weakly associated with psychological distress (rs = .18-.36), SS burden was moderately related to depression, anxiety and stress (rs = .47-.53).

CONCLUSIONS

TS burden can serve as a proxy for global TMD severity and may be more meaningful than the mere presence of TMD symptoms in clinical and research settings.

Temporomandibular disorder pain is associated with increased sick leave and reduced health related quality of life

BACKGROUND

Temporomandibular disorders (TMD) are the most common reason for chronic pain in the orofacial area and significantly impact the lives of those affected. The role of lifestyle factors in TMD, however, remains less explored. This cohort study aims to estimate TMD prevalence by addressing potential selection biases and to evaluate the association between TMD and lifestyle factors with a specific focus on sick leave and health related quality of life.

METHODS

By linking data on TMD in the general population in Västerbotten, northern Sweden (n = 180,000) to health survey data (n = 120,000), information on sociodemographic factors and quality of life was available for 52,961 individuals (50.6% women) with a mean age of 53 years. We applied inverse probability weighting to adjust for selection bias and Poisson regression to explore associations with TMD.

RESULTS

TMD prevalence was 9.2% during the study period, being higher in women (12.9%) than men (5.4%). Weighting for varying visiting frequencies did not affect TMD prevalence (average difference 0.4% points). Individuals with TMD, especially women, reported more sick leave and use of pain medication, with a significant association between TMD and increased sick leave (prevalence ratio 1.89, 95% CI: 1.78-2.01) among both women and men. In addition, TMD was associated with a lower health related quality of life (p < 0.001).

CONCLUSION

The association of TMD with sick leave highlights the condition's profound impact on the lives of affected individuals. These findings underscore the influence of TMD on work life and the burden of TMD on the societal level.

SIGNIFICANCE STATEMENT

The findings provide insight into how TMD affect individuals, by incorporating lifestyle factors, social determinants and the impact of sick leave at a population level. By incorporating these areas into the study of TMD, we can deepen our understanding of how TMD affects individuals' lives. This approach may also create opportunities to develop more comprehensive strategies to address TMD, focusing on broader implications beyond the clinical symptoms.

Chronic stress induces wide-spread hyperalgesia: The involvement of spinal CCK1 receptors

Chronic primary pain (CPP) occurs in the absence of tissue injury and includes temporomandibular disorders (TMD), fibromyalgia syndrome (FMS) and irritable bowel syndrome (IBS). CPP is commonly considered a stress-related chronic pain and often presents as wide-spread pain or comorbid pain conditions in different regions of the body. However, whether prolonged stress can directly result in the development of CPP comorbidity remains unclear. In the present study, we adapted a 21 day heterotypic stress paradigm in mice and examined whether chronic stress induced wide-spread hyperalgesia, modeling comorbid CPP in the clinic. We found that chronic stress induced anxiety- and depression-like behaviors, and resulted in long-lasting wide-spread hyperalgesia over several body regions such as the orofacial area, hindpaw, thigh, upper back and abdomen in female mice. We further found that the expression of cholecystokinin (CCK)1 receptors was significantly increased in the L4-L5 spinal dorsal horn of the female mice after 14 and 21 day heterotypic stress compared with the control animals. Intrathecal injection of the CCK1 receptor antagonist CR-1505 blocked pain hypersensitivity in the subcervical body including the upper back, thigh, hindpaw and abdomen. These findings suggest that the upregulation of spinal CCK1 receptors after chronic stress contributes to the central mechanisms underlying the development of wide-spread hyperalgesia, and may provide a potential and novel central target for clinical treatment of CPP.

Impact of migraine and fibromyalgia on temporomandibular disorder: A retrospective study on pain, psychological factors and quality of life

OBJECTIVES

This study assessed the impact of migraine and fibromyalgia (FM) in TMD patients, focusing on pain, anxiety, depression, and quality of life (QoL). Additionally, we investigated how these variables relate to the total number of comorbidities to gain insights into their interactions.

METHODS

A retrospective data collection was conducted during January 2016 to December 2022, involving 409 adult TMD patients. TMD patients were categorised into four groups: those without comorbidity (TMD-only) and those with comorbid migraine and/or fibromyalgia (TMD + MG, TMD + FM and TMD + MG + FM). Quantitative variables were compared among them. Linear regression was used to analyse the associations between these variables.

RESULTS

Most of study population were women (79%) with a mean age of 44.43 years. TMD + MG patients reported longer pain duration, higher pain scores and greater pain interference compared with TMD-only patients. Similarly, TMD + FM patients had higher pain intensity than patients with TMD only. Both the TMD + MG and TMD + FM groups had higher levels of anxiety, depression, and health impairment compared with patients with TMD only. Patients with all three pain conditions (TMD + MG + FM) experienced the longest pain duration, highest pain intensity, psychological distress, and impaired QoL. The result showed positive associations between pain outcomes, psychological measures, pain's impact on QoL, and the number of comorbidities and a negative association between overall health states and the number of comorbidities.

CONCLUSIONS

These findings underscore the importance of considering the presence of comorbidities and addressing physical and psychological aspects in the management of TMD patients.

Diaphragm dysfunction is found in patients with chronic painful temporomandibular disorder: A case-control study

Aim

To determine whether patients with chronic painful temporomandibular disorder (TMD) had abnormal diaphragm function compared to healthy controls and to explore the correlation between diaphragm contractility, psychological status, and pain characteristics.

Methods

A single-blinded, case-control study was conducted involving 23 chronic painful TMD patients and 22 healthy volunteers. The examination and diagnosis were performed according to the Diagnostic Criteria for Temporomandibular Disorders, and questionnaires were used to evaluate pain, depression, anxiety, and physical symptoms status. B-mode ultrasound was used to measure diaphragm thickness and contractility. The sonographer responsible for measuring the diaphragm was blinded to group membership.

Results

1. Depression, anxiety, and physical symptoms scores were significantly higher in the patients than in the controls (p < 0.05). 2. The Interference Score of pain was significantly correlated with depression and physical symptoms (p < 0.01). 3. Bilateral diaphragm contractility was significantly smaller in the patients than in the controls (right: P = 0.003; left: P = 0.001). 3. There was no correlation between diaphragm contractility on the left and right sides in the patients (r = -0.112, P = 0.611), while there was a positive correlation in the control group (r = 0.638, P = 0.001). 4. No correlation was found between the degree of diaphragm contractility, psychological status, and pain scores.

Conclusions

1. Patients with chronic painful TMD have worse psychological status, including depression, anxiety, and physical symptoms. 2. Patients with chronic painful TMD have a smaller degree of bilateral diaphragm contractility and more significant left-right incongruity, which indicated that diaphragm dysfunction may be correlated with chronic painful temporomandibular disorder.

Bruxism, temporomandibular disorders, and headache-a narrative review of correlations and causalities

ABSTRACT

The co-occurrence of bruxism, temporomandibular disorders (TMDs), and headache is common in patients. However, there is conflicting evidence regarding whether this association is simply a result of their high prevalence or whether there are indeed causal relationships. This review provides an overview of the current state of research while taking into account the controversies surrounding research methods, particularly in definitions and diagnostic standards. Bruxism-defined as repetitive jaw muscle activity during sleep or wakefulness-is not a painful disorder but may-particularly in co-occurrence with TMD-worsen pre-existing headache. It seems important to differentiate between sleep and awake bruxism because of different impact on pathophysiological processes in different primary headache disorders such as migraine and tension-type headache. Temporomandibular disorder is a heterogenous entity with both myofascial and arthrogenous types of pain in addition to nonpainful disorders. Research suggests a correlation between TMD pain and migraine, as well as between awake bruxism and tension-type headache. However, psychosocial factors may act as confounders in these relationships. Determining causality is challenging because of the limited number of experimental and clinical studies conducted on this topic. The main finding is an apparent lack of consensus on the definition and assessment criteria for bruxism. Treatment wise, it is important to differentiate all 3 conditions because treatment of one condition may have an effect on the other 2 without proving causality. For future research, it is crucial to establish greater consistency and applicability in diagnostic procedures and definitions. In addition, more experimental and clinical studies investigating the question of causality are needed.

Prevalence and associations of temporomandibular disorders in older Brazilian adults

OBJECTIVE

The objective of the study was to estimate the prevalence of temporomandibular disorders (TMD) and describe associations in a representative sample of community-dwelling older Brazilian adults.

BACKGROUND

TMD cause recurrent or chronic pain and dysfunction with substantial impacts on quality of life, but little is known of their occurrence and associated factors among older adults.

MATERIALS AND METHODS

This was a cross-sectional study using data from the second wave of the Brazilian Longitudinal Study of Aging, a nationally representative sample of older Brazilian adults aged 50 or older. The presence of temporomandibular disorder symptoms was measured by the Fonseca Anamnestic Index. Independent variables included sociodemographic characteristics, general health conditions and self-reported oral health measures. The association between the independent variables and TMD symptoms was evaluated using logistic regression models.

RESULTS

Complete information for the variables of interest was available for 9391 individuals. The overall prevalence of TMD symptoms was 18.0% (95% CI 14.4-22.1). Relative to older adults aged 50-59 those in all age categories had lower odds of TMD symptoms. Individuals with depression, pain, sleep problems and self-reported poor general health had higher odds of reporting TMD symptoms. None of the oral health measures were related to TMD.

CONCLUSION

The prevalence of TMD symptoms among Brazilian older adults is associated with demographic and general health conditions, but not with dentition status.

Temporomandibular disorder and somatic symptoms: Relations to 'fear of missing out' and other negative emotional states

OBJECTIVE

The association between the 'fear of missing out (FOMO)' and physical symptoms has not been widely explored. This study aimed to investigate the relationship between FOMO and other negative emotions with Temporomandibular disorder (TMD) and somatic symptoms in young adults. The correlations between the various physical and emotional variables were also established.

MATERIAL AND METHODS

TMD and somatic symptoms were appraised with the Short-form Fonseca Anamnestic Index, quintessential five TMD symptoms of the Diagnostic Criteria (DC)/TMD, and Patient Health Questionnaire-15. FOMO and other negative emotional states were assessed with the FOMO Scale and Depression, Anxiety, Stress Scales-21 (DASS-21). Data were evaluated using non-parametric tests/correlation and regression analysis (α = 0.05).

RESULTS

While only negative affectivity (total DASS), anxiety, and stress differed significantly between those without and with TMDs, significant variances in FOMO and all DASS-21 constructs were discerned between individuals without and with somatization.  Conclusions: Individuals with orofacial pain and more severe somatic symptoms have higher levels of negative emotions including FOMO. While somatization increased the prospect of TMDs, being female, presence of TMDs, and negative affectivity were risk factors for somatization in young adults.

CLINICAL RELEVANCE

Asian young adults appear to be disposed to somatization, and TMDs may be a form of functional somatic syndromes. Recognition of somatic symptoms and emotional distress, including FOMO, is essential for person-centric TMD care.

Comorbidities between temporomandibular disorders and somatization in young adults: exploring links with personality, emotional, and sleep disturbances

OBJECTIVE

The comorbidities between temporomandibular disorders (TMDs) and somatization and their associations with personality traits, emotional disorders, and sleep disturbances were investigated.

STUDY DESIGN

Adults aged 18 to 24 years completed an electronic survey encompassing TMD symptoms (5Ts), Patient Health Questionnaire-15, Big Five Personality Inventory-10, Depression Anxiety Stress Scales-21, and Pittsburgh Sleep Quality Index. Data were assessed using non-parametric tests/correlation analysis and logistic regression analysis (α = 0.05).

RESULTS

The sample comprised 365 participants, of whom 22.2% and 19.5% were 5Ts-negative without and with somatization, respectively, and 18.1% and 40.3% were 5Ts-positive without and with somatization, respectively. Significant differences in neuroticism, distress, depression, anxiety, stress, and sleep quality were observed between 5Ts-negative participants with somatization and 5Ts-positive participants with somatization compared with 5Ts-negative participants without somatization and 5Ts-positive participants without somatization. Distress, anxiety, stress, and sleep were moderately correlated with somatic but not TMD symptoms (rs = 0.45-0.52).

CONCLUSIONS

Irrespective of whether they had TMDs, participants with somatization exhibited heightened levels of neuroticism and emotional and sleep disturbances.

Comparison of low-level laser therapy and standard treatment for temporomandibular disorders: An assessment of therapeutic and placebo effects

BACKGROUND

Despite extensive research on the use of low-power lasers for TMD treatment, the extent of their effectiveness remains uncertain.

OBJECTIVE

This study aimed to investigate the therapeutic or placebo effect of LLLT for TMD, and to compare it with standard treatment methods. A unique aspect of this study was the inclusion of a control group that received only standard treatment, allowing for an assessment of the placebo effect of LLLT.

METHODS

A total of 42 patients with TMD were referred to Kerman Dental School Pain Clinic and were randomly assigned to three groups: group A received LLLT, group B was a placebo group and group C was a control group that received only standard treatment. The laser groups received gallium-aluminium-arsenide laser treatment twice a week for 10 sessions. Patients' jaw movement rate indicators and VAS index were evaluated at the start of treatment, and indicators were re-recorded every week for 5 weeks. SPSS 21 was used for statistical analysis, including ANOVA and Tukey's post hoc tests for inter-group comparisons. The repeated measurement test was used to analyse the data.

RESULTS

All groups showed significant improvement in VAS indicators (p = .0001), lateral jaw movements (p = .0001), forward jaw movement (p = .007) but not for maximum mouth opening. No significant difference was observed between the groups at the end of the study (p = .000).

CONCLUSION

Our study provides insights into LLLT's effectiveness for TMD, suggesting it cannot replace standard treatment alone. These findings contribute to the literature and emphasise the importance of including a control group in future studies to assess the placebo effect of LLLT.

Comorbid psychiatric conditions with temporomandibular disorders (TMD) in a tertiary referral clinic

Patients with chronic pain have a higher prevalence of mood disorders with depression and anxiety contributing to higher pain intensity, emotional allodynia, and neuro-anatomical changes. We sought to quantify the prevalence of psychiatric comorbidities (PCs) in a tertiary referral clinic for temporomandibular disorders (TMDs). Medical records of all patients attending clinics run by three tertiary temporomandibular joint (TMJ) surgeons for the period January to April 2022 inclusive were audited for the prevalence of concomitant psychiatric conditions. A total of 166 patients were identified with a female to male ratio of 5:1 and mean (SD) age of 45.1 (15.2) years. A total of 124 (89.9%) patients were tertiary referrals and 72 (43.4%) patients had concomitant psychiatric diagnoses, with 58 (34.9%) being on some form of psychotropic medication (PM) (patients on anticonvulsants for neuropathic pain were not included). A majority of 136 (81.9%) patients had some form of intervention (including Dysport® and minimally invasive surgery) which appeared more common in patients with co-existing psychiatric issues (p < 0.05). A higher proportion of mental health issues exist among TMD patients in a tertiary referral clinic than would be expected in the general population. We suggest a holistic approach to patients with multidisciplinary care taking into account this prevalence to ensure decision-making that contextualises the patient and not simply the pathology.

Is painful temporomandibular disorder a real headache for many patients?

Temporomandibular disorders (TMDs) and primary headaches are common pain conditions and often co-exist. TMD classification includes the term 'headache secondary to TMD' but this term does not acknowledge the likelihood that primary headache pathophysiology underpins headache causing painful TMD signs and symptoms in many patients. The two disorders have a complex link and we do not fully understand their interrelationship. However, growing evidence shows a significant association between the two disorders. This article reviews the possible connection between temporomandibular disorders and primary headaches, specifically migraine, both anatomically and pathogenetically.

Temporomandibular disorder pain in older adolescents-young adults: Interrelationship with somatic burden, mental ill-being, and well-being

OBJECTIVES

The associations of Temporomandibular disorder (TMD) pain with somatic symptoms, mental ill-being/distress, and well-being were explored, along with the mental correlates of TMD (TS) and somatic symptom (SS) burden in older adolescents-young adults.

METHODS

TMD/somatic symptoms were appraised with the five quintessential symptoms (5Ts) of the DC/TMD/Somatic Symptom Scale-8, whereas mental distress/well-being was assessed with the Depression, Anxiety, Stress Scales-21/Scales of Psychological Well-being-18. Data were examined using Chi-square/non-parametric tests and multivariate analyses (α = .05).

RESULTS

Among the 366 participants, 51.4%, 28.1%, 6.8%, and 13.7% had no TMD (NT), TMD pain (TP), TMD dysfunction (TD), and combined TMD (CT) respectively. Though mental distress varied substantially (CT, TP>NT, TD), no significant differences in well-being were discerned. SS burden, but not TS burden, was moderately correlated to distress.

CONCLUSIONS

The prospect of TMD pain was increased by being female, depressed, and anxious but reduced by "positive relations with others" and "self-acceptance".

Additional effects of therapeutic exercise and education on manual therapy for chronic temporomandibular disorders treatment: a randomized clinical trial

BACKGROUND

Previous studies have evaluated the implementation of behavioral approaches in individuals with chronic temporomandibular disorders (TMDs).

OBJECTIVE

To evaluate the benefits of a behavioral approach to craniofacial pain. Second, we assessed the benefits of kinesiophobia, catastrophizing, mouth opening without pain, and forward head posture.

METHODS

Individuals with chronic TMDs were treated for five weeks. The intervention group (n = 17) underwent pain neuroscience education, manual therapy, and therapeutic exercise, whereas the control group (n = 17) underwent manual therapy only. Outcomes were evaluated immediately, at seven and 19 weeks follow-up. The assessment tools used were the Craniofacial Pain Disability Inventory, Pain Catastrophizing Scale, Tampa Scale for Kinesiophobia, Mandibular Range of Motion Scale, and Cervical Range of Motion Tool.

RESULTS

The interventions did not influence the differences in the improvements between the groups observed for craniofacial pain disability (inter-subject p 0.4). The intervention had a moderate influence on the improvement of kinesiophobia and catastrophizing (Inter-subject p 0.09 and 0.1 respectively) with a clinically significant effect size (Estimated mean (EM) -8.6 standard deviation (SD) ±3.48 p 0.019; and EM -7.6 SD ± 5.11 p 0.15 respectively).

CONCLUSION

The behavioral approach improved catastrophizing and kinesiophobia outcomes in individuals with chronic TMDs.

Is low back pain a risk/prognostic factor for the development and/or progression of temporomandibular disorders? A systematic review with meta-analysis

OBJECTIVES

To evaluate the association between low back pain (LBP) and painful temporomandibular disorders (TMDs).

METHODS

Systematic review of observational studies. Searches were conducted using OVID MEDLINE, CINHAL, Web of Science and PUBMED databases up to 21 October 2022. Qualitative and quantitative analyses were performed. Risk of bias (RoB) was assessed using the Quality in Prognosis Studies tool (QUIPS).

RESULTS

Eight studies were included in the present review with meta-analysis. The first onset of TMDs was more likely in patients with previous chronic LBP (hazard ratio (HR) 1.53 [95% confidence interval (CI): 1.28; 1.83, p < .00001]). In addition, patients with chronic LBP had 3.25 times the odds (OR) [95% CI: 1.94; 5.43, p < .00001] of having chronic TMDs than those who did not have chronic LBP. In addition, the higher the exposure to chronic LBP, the higher the risk of developing a first onset of TMDs.

CONCLUSIONS

Chronic LBP can be considered a risk/contributing factor for painful TMDs. Although there is a high certainty in the evidence linking chronic LBP with the risk of a first onset of TMDs, there are insufficient studies to draw definitive conclusions. Furthermore, while an association between chronic LBP and chronic TMDs and a dose-effect was observed between these two conditions, a limited number of studies and evidence exist to support these findings. Future studies are needed to increase the body of evidence.

Correlates of jaw functional limitation, somatization and psychological distress among different temporomandibular disorder diagnostic subtypes

OBJECTIVES

This study investigated the jaw functional status and severity of somatic/psychological symptoms in different Diagnostic Criteria for temporomandibular disorders (DC/TMD) diagnostic subtypes and established the correlates between jaw functional limitation, somatization, depression and anxiety.

METHODS

Data were accrued from consecutive 'first-visit' patients seeking TMD treatment at a university-based oral medicine/diagnosis clinic. Axis I physical TMD diagnoses were derived using the DC/TMD methodology and patients were categorized into pain-related (PT), intra-articular (IT) and combined (CT) TMD groups. Axis II measures were also administered and included the Jaw Functional Limitation Scale-20 (JFLS-20), Patient Health Questionnaire-15 and 9 (PHQ-15 and PHQ-9) and General Anxiety Disorder Scale-7 (GAD-7). Chi-square/Kruskal-Wallis tests and Spearman's correlation were employed for statistical evaluations (α = .05).

RESULTS

The final dataset consisted of 772 TMD patients (mean age of 37.7 ± 15.9 years; 70.2% females). The prevalence of PT, IT and CT was 11.9%, 15.7% and 72.4%, respectively. Significant differences in functional jaw limitations, somatization, depression (CT, PT > IT) and anxiety (CT > PT, IT) were observed. Moderate-to-severe somatization, depression and anxiety were detected in 12.6%-15.7% of patients. For all three TMD groups, JFLS global scale/subscale scores were weakly associated with somatization, depression and anxiety scores (rs  < 0.4). Moderate-to-strong correlations were noted between somatization, depression and anxiety (rs  = 0.50-0.74).

CONCLUSIONS

Functional jaw limitations were associated with painful TMDs but appear to be unrelated to somatization and psychological distress. Somatization and depression/anxiety were moderately correlated, underscoring the importance of somatic symptom screening when managing TMD patients.

Psychological characteristics of young adults with temporomandibular disorders, somatization and combined conditions: A multidimensional evaluation

BACKGROUND

Temporomandibular disorders and somatization have shown interrelation in many studies. The physical and psychological factors which contributed to the occurrence and relation of both conditions are yet to be determined.

OBJECTIVES

The personality traits, coping styles and psychological distress of young adults with temporomandibular disorder (TMD) and somatic symptoms were characterized together with the determination of psychological risk factors for TMDs, somatization and combined conditions.

METHODS

Participants were recruited from university-attending young adults. TMD and somatic symptoms were appraised with the short-form Fonseca Anamnestic Index and Patient Health Questionnaire-15. Psychological variables were assessed with the Big Five Personality Inventory-10, Brief-COPE Inventory and Depression, Anxiety, and Stress Scales-21. Data were evaluated using chi-squared/non-parametric tests and logistic regression analyses (α = .05).

RESULTS

Among the 507 participants (mean age 22.2 ± 1.5 years), 46.4% reported no TMD/somatic symptoms (NS) while 7.5%, 34.5% and 11.6% had TMDs only (TS), somatization only (SS) and combined TMDs-somatization (CS), respectively. Significant differences in conscientiousness (NS > SS), agreeableness (NS, TS > CS; NS > SS), dysfunctional coping, general distress, depression, anxiety and stress (CS ≥ SS > NS) were discerned. Multivariate analyses indicated that the odds of TS were increased by anxiety (OR = 1.10; 95% CI = 1.01-1.21), while the odds of SS/CS were affected by anxiety (OR = 1.15; 95% CI = 1.06-1.25/OR = 1.34; 95% CI = 0.19-1.52) and problem-focused coping (OR = 0.71; 95% CI = 0.56-0.89/OR = 0.55; 95% CI = 0.39-0.78).

CONCLUSION

Though individuals with TMDs and somatization have dissimilar psychological profiles, anxiety constantly increased their likelihood. Problem-focused coping strategies may help alleviate psychosocial and physical stressors associated with TMDs and somatization.

Effect on orofacial pain in patients with chronic pain participating in a multimodal rehabilitation programme - a pilot study

OBJECTIVES

Orofacial pain in patients taking part in a multimodal rehabilitation programme (MMRP) due to chronic bodily pain is common but it is not known whether such a rehabilitation programme can also have an effect on the presence of orofacial pain. The first aim of this study was to evaluate the effect of an MMRP on orofacial pain frequency. The second aim was to evaluate differences in the effect on quality of life and on psychosocial factors related to chronic pain.

METHODS

MMRP was evaluated through validated questionnaires from the Swedish Quality Registry for Pain Rehabilitation (SQRP). Fifty-nine patients participating in MMRP filled out the two screening questions for orofacial pain in addition to the SQRP questionnaires before and after participation in MMRP during the period August 2016 to March 2018.

RESULTS

Pain intensity decreased significantly after the MMRP (p=0.005). Fifty patients (69.4 %) reported orofacial pain before MMRP and no significant decrease after the programme (p=0.228). Among individuals with orofacial pain, the self-reported level of depression decreased after participation in the programme (p=0.004).

CONCLUSIONS

Even though orofacial pain is common among patients with chronic bodily pain, participation in a multimodal pain programme was not enough to reduce frequent orofacial pain. This finding implies that specific orofacial pain management including information about jaw physiology could be a justified component of patient assessment prior to a multimodal rehabilitation programme for chronic bodily pain.

Painful temporomandibular disorders in Confucian-heritage cultures: Their inter-relationship with bodily pain, psychological well-being and distress

BACKGROUND

Temporomandibular disorders (TMDs) are common and affect individuals negatively.

OBJECTIVES

This study investigated the inter-relationship of painful TMDs with bodily pain, psychological well-being and distress in young people from a Confucian-heritage culture (CHC).

METHODS

Adolescents/young adults were recruited from a polytechnic in Singapore. While the presence/severity of painful TMDs and bodily pain were established with the DC/TMD Pain Screener (TPS) and Maciel's Pain Inventory, psychological well-being and distress were evaluated with the Scales of Psychological Well-being-18 (SPWB-18) and Patient Health Questionnaire-4 (PHQ-4). Statistical explorations were conducted using chi-square/Mann-Whitney U tests, Spearman's correlation and logistic regression analyses (α = .05).

RESULTS

Among the 225 participants (mean age 20.1 ± 3.9 years) examined, 11.6% had painful TMDs and 68.9% experienced multisite bodily pain. Though painful TMDs were accompanied by a higher occurrence of multisite bodily pain, the overall/discrete number of bodily pain sites did not differ substantially between the 'no TMD pain' (NT) and 'with TMD pain' (WT) groups. Besides ear pain, differences in overall/discrete bodily pain scores were also insignificant. However, significant differences in environmental mastery, overall psychological distress, depression and anxiety subscale scores were discerned between the NT and WT groups. Psychological well-being and distress were moderately and negatively correlated (rs  = -.56). Multivariate analysis indicated that ear pain and psychological distress increased the prospect of painful TMDs.

CONCLUSION

The prevalence of multi-site bodily pain was high in young people from CHCs irrespective of the painful TMDs' presence of painful TMDs. Enhancing environmental mastery and relieving depression/anxiety may help manage TMD pain.

An Update on Temporomandibular Disorders (TMDs) and Headache

PURPOSE OF REVIEW

To provide an overview and highlight recent updates in temporomandibular disorders (TMDs) and their comorbidity with headache disorders regarding pathophysiology and management.

RECENT FINDINGS

In the last decade, there have been great advancements in the understanding of TMDs and their relationship with neurovascular pains such as headaches. Understanding of TMDs is necessary for the context of its comorbidity with primary headache disorders. The literature regarding management of these comorbidities is scarce but points to combination therapy including pharmacological and non-pharmacological approaches to optimize management. The use of CGRP receptor-targeted monoclonal antibodies or CGRP receptor antagonists should be explored for the management of chronic TMDs. It could also be used as a novel monotherapy or in combination with non-pharmacological approaches for TMDs' comorbidity with headache, particularly migraine. Research is needed to support evidence-based management protocols. A team involving neurology (headache medicine) and dentistry (orofacial pain) is critical for optimal management.

Pharmacological Management of Orofacial Pain

Orofacial pain is a category of complex disorders, including musculoskeletal, neuropathic and neurovascular disorders, that greatly affect the quality of life of the patient. These disorders are within the fields of dentistry and medicine and management can be challenging, requiring a referral to an orofacial pain specialist, essential for adequate evaluation, diagnosis, and care. Management is specific to the diagnosis and a treatment plan is developed with diverse pharmacological and non-pharmacological modalities. The pharmacological management of orofacial pain encompasses a vast array of medication classes and approaches. This includes anti-inflammatory drugs, muscle relaxants, anticonvulsants, antidepressants, and anesthetics. In addition, as adjunct therapy, different injections can be integrated into the management plan depending on the diagnosis and needs. These include trigger point injections, temporomandibular joint (TMJ) injections, and neurotoxin injections with botulinum toxin and nerve blocks. Multidisciplinary management is key for optimal care. New and safer therapeutic targets exclusively for the management of orofacial pain disorders are needed to offer better care for this patient population.

DC/TMD Axis I diagnostic subtypes in TMD patients from Confucian heritage cultures: a stratified reporting framework

OBJECTIVES

This study proposed a conceptual framework for reporting Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) Axis I conditions and investigated the prevalence of TMD subtypes/categories in patients from Confucian heritage cultures. Variances in gender, age, and TMD chronicity between Chinese (CN) and Korean (KR) patients were also explored.

MATERIALS AND METHODS

Subjects were recruited from consecutive patients seeking care at two University-based centers in Beijing and Seoul. Eligible patients completed a demographic survey as well as the DC/TMD Symptom Questionnaire and were clinically examined according to the DC/TMD methodology. Axis I diagnoses were subsequently rendered with the DC/TMD algorithms and documented using the stratified reporting framework. Statistical evaluations were performed with chi-square, Mann-Whitney U tests, and logistic regression analysis (α = 0.05).

RESULTS

Data of 2008 TMD patients (mean age 34.8 ± 16.2 years) were appraised. Substantial differences in female-to-male ratio (CN > KR), age (KR > CN), and TMD duration (KR > CN) were observed. Ranked frequencies of the most common Axis I diagnoses were: CN - disc displacements (69.7%) > arthralgia (39.9%) > degenerative joint disease (36.7%); KR - disc displacements (81.0%) > myalgia (60.2%) > arthralgia (56.1%). Concerning TMD categories, notable differences in the prevalence of intra-articular (CN 55.1% > KR 15.4%) and combined (KR 71.8% > CN 33.4%) TMDs were discerned.

CONCLUSIONS

Though culturally similar, the two countries require disparate TMD care planning/prioritization. While TMJ disorders in children/adolescents and young adults should be emphasized in China, the focus in Korea would be on TMD pain in young and middle-aged adults.

CLINICAL RELEVANCE

Besides culture, other variables including socioeconomic, environmental, and psychosocial factors can influence the clinical presentation of TMDs. Chinese and Korean TMD patients exhibited significantly more intra-articular and combined TMDs respectively.

External validation of a clinical prediction tool for the use of manual therapy for patients with temporomandibular disorders: a protocol for a prospective observational study

INTRODUCTION

Clinical guidelines recommend conservative treatment for the management of temporomandibular disorders (TMD), and manual therapy directed to temporomandibular structures is commonly applied to reduce pain and improve function. In a recent prospective study, we developed a clinical prediction tool based on an array of predictors to identify people with TMD who are likely to experience significant pain relief and functional improvements following a programme of manual therapies (MTP) applied to temporomandibular structures. The purpose of this study is to externally validate in a different sample (temporal validation) the prediction model obtained in the initial study.

METHODS/ANALYSIS

This observational prospective study will recruit a cohort of 120 adults with TMD from a Dental Hospital in Italy. The intervention will be an MTP consisting of four sessions (once per week) of manual therapy applied to temporomandibular structures. Candidate predictors included in the predictive model will be pain intensity during mouth opening, treatment expectations, number of pain locations, central sensitisation, TMD pain duration and maximal mouth opening. Outcome measures (i.e., pain intensity, functional improvement) will be collected before starting the MTP, after the last session and after 1 month (2 months from baseline). A reduction of pain intensity by at least 30% will be considered a good outcome. External validity of the prediction model will be evaluated after the last session by measuring its calibration, discrimination and overall fit. Additionally, the performance of the model will be evaluated considering the clinical outcomes collected 1 month after the last MTP session.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the Ethics Committee of the Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Italy. The results will be submitted for publication in a peer-reviewed journal, and the prediction model will be implemented in a web-based calculator to facilitate its use by clinicians.

TRIAL REGISTRATION NUMBER

NCT03990662.

Classifying migraine using PET compressive big data analytics of brain's μ-opioid and D2/D3 dopamine neurotransmission

Introduction: Migraine is a common and debilitating pain disorder associated with dysfunction of the central nervous system. Advanced magnetic resonance imaging (MRI) studies have reported relevant pathophysiologic states in migraine. However, its molecular mechanistic processes are still poorly understood in vivo. This study examined migraine patients with a novel machine learning (ML) method based on their central μ-opioid and dopamine D2/D3 profiles, the most critical neurotransmitters in the brain for pain perception and its cognitive-motivational interface. Methods: We employed compressive Big Data Analytics (CBDA) to identify migraineurs and healthy controls (HC) in a large positron emission tomography (PET) dataset. 198 PET volumes were obtained from 38 migraineurs and 23 HC during rest and thermal pain challenge. 61 subjects were scanned with the selective μ-opioid receptor (μOR) radiotracer [11C]Carfentanil, and 22 with the selective dopamine D2/D3 receptor (DOR) radiotracer [11C]Raclopride. PET scans were recast into a 1D array of 510,340 voxels with spatial and intensity filtering of non-displaceable binding potential (BPND), representing the receptor availability level. We then performed data reduction and CBDA to power rank the predictive brain voxels. Results: CBDA classified migraineurs from HC with accuracy, sensitivity, and specificity above 90% for whole-brain and region-of-interest (ROI) analyses. The most predictive ROIs for μOR were the insula (anterior), thalamus (pulvinar, medial-dorsal, and ventral lateral/posterior nuclei), and the putamen. The latter, putamen (anterior), was also the most predictive for migraine regarding DOR D2/D3 BPND levels. Discussion: CBDA of endogenous μ-opioid and D2/D3 dopamine dysfunctions in the brain can accurately identify a migraine patient based on their receptor availability across key sensory, motor, and motivational processing regions. Our ML-based findings in the migraineur's brain neurotransmission partly explain the severe impact of migraine suffering and associated neuropsychiatric comorbidities.

Temporomandibular Joint Disorder Comorbidities

Comorbidity is a distinct additional condition that either existed or exists during the clinical course of a patient afflicted by the condition/entity in question. The clinician attempting to manage temporomandibular joint disorder (TMD) and TMD pain must realize that recognition and management of the comorbidities are essential to the successful management of the same with optimal pain control. When TMD presents with multiple comorbidities, the task for the clinician becomes more complex. It is the hope of the authors that this condensed version of TMD-associated comorbidities acts as a primer for understanding the significance of the same in pain management.

Efficiency of occlusal splint therapy on orofacial muscle pain reduction: a systematic review

BACKGROUND

This systematic review aims to examine the existing original studies to determine the effectiveness of occlusal splints (OSs) in the management of orofacial myalgia and myofascial pain (MP) in comparison with no treatment or other interventions.

MATERIALS AND METHODS

Based on the inclusion and exclusion criteria of this systematic review, randomized controlled trials were qualified, in which the effectiveness of occlusal splint therapy in the management of muscle pain was examined in comparison with no treatment or other interventions. This systematic review was conducted according to the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analysis 2020. The authors searched three databases (PubMed, CINAHL (The Cumulative Index to Nursing and Allied Health Literature) and Scopus) for English publications published between January 1, 2010, and June 1, 2022. The last database search was carried out on June 4, 2022. Data were extracted from the included studies and assessed for risk of bias using the revised Cochrane risk-of-bias tool for randomized trials.

RESULTS

Thirteen studies were identified for inclusion in this review. In total, 589 patients were diagnosed with orofacial muscle pain who underwent education and various forms of therapy including different types of OSs, light emitting diode therapy, acupuncture, low-level laser therapy, device-supported sensorimotor training, Kinesio Taping, myofunctional therapy, and physical therapy. All studies included demonstrated a high risk of bias.

CONCLUSIONS

There is insufficient evidence regarding whether OS therapy in the treatment of orofacial myalgia and MP offers an advantage over other forms of interventions or no treatment. Further reliable clinical studies in this area are needed to improve the quality of research, which should be performed with larger groups of blinded respondents and controls.

CLINICAL RELEVANCE

Due to the large-scale nature of orofacial muscle pain, it is assumed that each dental clinician will meet patients with orofacial muscle pain repeatedly in daily practice; hence, the review of the effectiveness of OSs in the management of orofacial myalgia and MP is necessary.

Posttraumatic Stress Disorder and the Role of Psychosocial Comorbidities in Chronic Orofacial Pain

This article presents the case of a patient with persistent right-sided jaw pain with a history of multiple temporomandibular joint surgeries in the setting of persistent widespread body pain, the causes of which were fibromyalgia and osteoarthritis with multiple joint replacements, as well as psychological diagnoses of PTSD and depression. Despite extensive treatment from her orofacial pain team in combination with neurology and neurosurgery, her severe pain persisted, likely due to the consequences of untreated PTSD and depression, which led to avoidance of activities that would exacerbate her pain and thus to further disability and emotional deterioration.

CMD und Kieferorthopädie

Die Craniomandibuläre Dysfunktion (CMD) ist mit einer Prävalenz von über 30% die häufigste chronische Schmerzerkrankung im Kiefer- Gesichtsbereich. Die Therapie erfordert einen interdisziplinären, individuell angepassten Behandlungsansatz. Diese Fallvorstellung soll einen Einblick über das Behandlungskonzept eines posterior-lateralen Zwangsbisses mit Oberkiefer- Okklusionsschiene und OK/UK Alignern (Invisalign) geben.

Migraine in the context of chronic primary pain, chronic overlapping pain disorders, and functional somatic disorders: A narrative review

OBJECTIVE

To contextualize migraine as the most common primary headache disorder in relation to other chronic primary pain and non-pain functional somatic and mental conditions.

BACKGROUND

Migraine is increasingly understood as a sensory processing disorder within a broader spectrum of symptom disorders. This has implications for diagnosis and treatment.

METHOD

Narrative review based on a search of the literature of the last 15 years on the overlap of migraine with other symptom disorders.

RESULTS

Migraine as the prototypical primary headache disorder not only comprises many non-headache symptoms in itself, it also shows high comorbidity with other chronic pain and non-pain conditions (e.g., fibromyalgia syndrome, irritable bowel syndrome, functional non-epileptic seizures, depression, anxiety, and posttraumatic stress disorder). Such "symptom disorders" share several etiological factors (e.g., female preponderance, psychological vulnerability) and psychophysiological mechanisms (e.g., altered sensory processing, pain expectancy). These facts are acknowledged by several recent integrative conceptualizations such as chronic primary pain, chronic overlapping pain conditions, or functional somatic disorders. Accordingly, migraine management increasingly addresses the total symptom burden and individual contributors to symptom experience, and thus incorporates centrally acting pharmacological and non-pharmacological, that is, psychological and behavioral, treatment approaches.

CONCLUSIONS

Migraine and also other primary headache disorders should be seen as particular phenotypes within a broader spectrum of symptom perception and processing disorders that require integrative diagnostics and treatment. A harmonization of classifications and better interdisciplinary collaboration are desirable.

Triad Multisystem Phenotype with High-risk for Developing Temporomandibular Disorders- Characteristics and Potential Pathophysiology Results from the OPPERA Dataset

ABSTRACT

A multisystem phenotype with the Triad of bodily pain, psychological distress, and sleep disturbance was found to have high risk for developing initial onset of painful temporomandibular disorders (TMDs) in the multicenter Orofacial Pain: Prospective Evaluation and Risk Assessment (OPPERA) dataset. In this study, we systemically examined phenotypic characteristics and explored potential pathophysiology in quantitative sensory testing (QST) and autonomic nervous system (ANS) domains in this multisystem Triad phenotype. Secondary analysis was performed on 1199 non-Triad and 154 Triad TMD-free OPPERA enrollees at baseline. Results indicate that prior to developing TMDs, the Triad phenotype demonstrated both orofacial and systemic signs and symptoms that can only be captured through multisystem assessment. In addition, we found significantly lower resting heart rate variability and higher resting heart rate in the Triad phenotype as compared to the non-Triad group. However, pain sensitivity measured by QST was not different between groups. These findings highlight the importance of whole-person multisystem assessment at the stage prior to developing complex pain conditions such as TMDs, and suggest that, in addition to a "tissue damage monitor", pain should be considered in a broader context, such as a component within a "distress monitoring system" at the whole-person level when multisystem issues co-present. Therefore, the presence or absence of multisystem issues may carry critical information when searching for disease mechanisms and developing mechanism-based intervention and prevention strategies for TMDs and related pain conditions. Cardiovascular autonomic function should be further researched when multisystem issues co-present prior to developing TMDs.

Differential Sensitization of Muscle versus Fascia in Individuals with Low Back Pain

Muscles and the deep fascia surrounding them have been suggested to play an important role in various musculoskeletal pain conditions including low back pain. Both have been shown to host rich nociceptive innervation and to undergo changes in individuals with chronic pain. However, evidence for the respective contribution of muscle and fascia sensitization in humans with myofascial pain syndrome is lacking. Here, we studied the sensitization of muscle and fascia in individuals with myofascial low back pain. Twenty individuals with acute (5) and chronic (15) myofascial low back pain of the quadratus lumborum muscle and a matched control group of twenty healthy individuals were recruited and clinically evaluated. All participants underwent ultrasound-guided needling of their subcutaneous tissue, deep fascia and quadratus lumborum muscle. Reported pain intensity and episodes of muscle twitching were recorded and analyzed. Among pain patients, both muscles and deep fascia demonstrated pain hypersensitivity, but muscles were significantly more sensitized than the deep fascia. No difference between acute- or chronic-pain patients was observed. Results of this study suggest that while both deep fascia and muscle show pain sensitization in both early and chronic stages of low back pain, muscles are more sensitized than fascia.

Evidence for alterations to dynamic quantitative sensory tests in patients with chronic temporomandibular myalgia: a systematic review of observational studies with meta-analysis

BACKGROUND

Conflicting results exist between somatosensory profiles of patients with temporomandibular myalgia (TMDm). The objective of this review was to examine whether adults with TMDm show altered responses to dynamic quantitative sensory tests compared with healthy controls.

METHODS

We searched five electronic databases for studies, excluding those without suitable controls or where TMDm was associated with confounding non-musculoskeletal disorders. Risk of bias was assessed with the SIGN case-control study checklist. Findings were structured around dynamic quantitative sensory tests and their localization. Where possible, we performed meta-analysis with a random inverse variance model to compare patients with TMDm and healthy controls. Statistical heterogeneity was estimated with Chi² test and inconsistency index, I².

RESULTS

We extracted data from 23 studies comprising 1284 adults with chronic TMDm and 2791 healthy controls. Risk of bias was assessed as high for 20 studies. Mechanical temporal summation, the most studied phenomenon (14 studies), is increased in the upper limb of patients with TMDm (SMD = .43; 95% CI: .11 to .75; p = .0001) but not in the jaw area (p = .09) or in the cervical area (p = .29). Very little evidence for altered thermal temporal summation (five studies), conditioned pain modulation (seven studies), exercise-induced hypoalgesia (two studies), placebo analgesia (two studies), stress-induced hypoalgesia (one study) and offset analgesia (one study) was found.

DISCUSSION

A major limitation of this review was the risk of bias of included studies. Future studies would benefit from following methodological guidelines and consideration of confounding factors.