Temporomandibular disorders and painful comorbidities: clinical association and underlying mechanisms

The Temporomandibular Joint and the Human Body: A New Perspective on Cross Talk

Background: As a unique joint that facilitates the articulation of the upper and lower jaws, the temporomandibular joint (TMJ) is concerned with several critical functions, such as speech and mastication. Pain that can become incapacitating is a result of temporomandibular disorders (TMDs), which are complex disorders affecting the masticatory muscles and the TMJ. Several anomalies and TMDs have an interdisciplinary relationship. Complementary and concurrent disorders may be caused by occlusal anomalies, psychological disorders, and changes in spine posture. Methods: This article examines the clinical characteristics of TMDs, their classification, their etiological factors, and the impact of TMJ disorders on the human body with reference to their anatomies and histological structures. Results: The clinical picture of some TMJ pathologies may be unknown, so certain biomarkers, such as cytokines, may be useful for an accurate diagnosis as they are frequently seen in TMJ disorders. Furthermore, novel therapeutic approaches that target pro-inflammatory cytokines and treat TMDs by using tissue engineering and regenerative medicine while permitting TMJ cartilage and bone regeneration may offer numerous benefits that require clinical translation. Conclusions: Implementation of recent modalities such as microvesicles and platelet-rich plasma in growth factors may provide a promising approach to enhance bone formation. In addition, we target different biological markers that give insights into the introduction of new pharmaceutical agents for therapy.

Up-regulation of IL-1β and sPLA2-III in the medial prefrontal cortex contributes to orofacial and somatic hyperalgesia induced by malocclusion via glial-neuron crosstalk

The medial prefrontal cortex (mPFC) has been identified as a key brain region involved in the modulation of chronic pain. Our recent study demonstrated that unilateral anterior crossbite (UAC) developed the comorbidity model of temporomandibular disorders (TMD) and fibromyalgia syndrome (FMS), which was characterized by both orofacial and somatic hyperalgesia. In the present study, UAC rats exhibited significant changes in gene expression in the mPFC. Enrichment analysis revealed that the significantly involved pathways were cytokines-cytokine receptor interaction and immune response. The expression of group III secretory phospholipase A2 (sPLA2-III) was significantly increased in the mPFC of UAC rats. Silencing sPLA2-III expression in the mPFC blocked the orofacial and somatic hyperalgesia. Immunofluorescence showed that sPLA2-III was mainly localized in neurons. The expression of interleukin-1β (IL-1β) in the mPFC significantly increased after UAC. Injection of IL-1β antibody into the mPFC blocked orofacial and somatic hyperalgesia. IL-1β was mainly localized in microglia cells. Furthermore, injection of IL-1β antibody significantly reduced the expression of sPLA2-III. These results indicate that neuroinflammatory cascade responses induced by glial-neuron crosstalk in the mPFC may contribute to the development of TMD and FMS comorbidity, and IL-1β and sPLA2-III are identified as novel potential therapeutic targets for the treatment of chronic pain in the comorbidity of TMD and FMS.

The association between neuropathic pain features and central sensitization with acute headache associated to a whiplash injury

BACKGROUND

Headache is one of the most common symptoms after a whiplash injury, although the pathophysiology remains under discussion. This study aimed to evaluate differences in neuropathic pain and central sensitization features between those who present with whiplash-associated headache (WAH) soon after a whiplash injury and those who do not.

METHODS

This case-control study evaluated differences on the self-administered Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS), Pain Detect Questionnaire (PDQ) and the Central Sensitization Inventory (CSI) between those who present with WAH in the acute phase after a whiplash injury (n = 46) and those who do not (n = 36). Moreover, the association of these variables in addition to neck pain intensity and the Neck Disability Index (NDI) score, with the presence of WAH was examined through logistic regression.

RESULTS

While differences between groups were found for both neuropathic and central sensitization features, only the presence of neuropathic pain features was associated with the presence of headache, with 27 scores for the S-LANSS and 23 for the PDQ from 46 people with headache (58.6% and 50.0%, respectively). The NDI and the S-LANSS partially explained (R2 = 0.68) the presence of WAH according to a logistic regression model.

CONCLUSION

Significant differences were found between people with whiplash with and without WAH when the S-LANSS, the PDQ and the CSI were assessed. S-LANSS and NDI were the variables most associated with the presence of WAH. These findings suggest that neuropathic pain features may be associated with the presence of acute WAH.

Risk factors for temporomandibular disorders: a systematic review of cohort studies

OBJECTIVE

A systematic review was performed to synthesize and identify risk factors involved in TMD onset.

STUDY DESIGN

Electronic searches were conducted in PubMed, Web of Science, Scopus, Embase, PsyInfo and Lilacs databases, as well as in three gray literature databases (Google Scholar, ProQuest and Open grey). The studies were blindly assessed by two reviewers and selected by a pre-defined eligibility criterion. Risk of bias of included studies was assessed using the Joanna Briggs Institute Critical Appraisal Checklist for Cohort Studies. Grading of Recommendations Assessment, Development and Evaluation (GRADE) was evaluated for most related factors.

RESULTS

Twenty-one cohort studies were included. Significant factors were female gender, symptoms of depression and anxiety, perceived stress, sleep quality, symptoms of obstructive sleep apnea and presence of any comorbidity, such as Irritable Bowel Syndrome, lower back pain, headache frequency, tension-type headache, migraine and mixed headache. Moreover, high estrogen and low testosterone levels in utero, greater pain perception, jaw mobility pain, pain during palpation, orofacial anomalies, as well as extrinsic and intrinsic injuries were also significant.

CONCLUSIONS

Several factors seems to be involved in TMD onset, however, more studies with standardized methodology are necessary to confirm these findings.

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.

Adherence to the Mediterranean Diet: A Tool to the Therapeutic Approaches for Patients With Temporomandibular Joint Disorders

BACKGROUND AND AIM

Temporomandibular joint disorder (TMD) is characterized by symptoms such as clenching, clicking, and locking of the jaw, often due to improper positioning affecting occlusion. Nearly half of TMD patients rarely require treatment, as symptoms typically diminish on their own within a year. Nevertheless, a significant majority of persons who are diagnosed with TMD do necessitate therapy, and it may take up to three years for complete remission to occur. This study aims to determine the extent to which a healthy nutritional model, specifically the Mediterranean diet, can enhance the effectiveness of existing therapeutic treatments, like physiotherapy with warm pads.

METHODS

An interventional study design was implemented. Baseline scores were obtained pre- and post-intervention, while Mediterranean diet adherence was evaluated once at the beginning. A dependent samples t-test and a one-way multivariate analysis of covariance (MANCOVA) were used to test the experimental hypotheses.

RESULTS

There is a statistically significant difference (p=0.04) between the three groups associated with Mediterranean diet adherence, as indicated by the mean differences on the Jaw Functional Limitation Scale (JFLS-20) questionnaire. Participants following a medium or high level of Mediterranean diet (≥18) reported fewer problems with jaw functionality both before and after the intervention compared to those with low (<18) adherence to the diet.

CONCLUSION

Adherence to the Mediterranean diet appears to have a therapeutic effect on patients with TMD, offering a new dimension to their treatment. The primary benefit is the low cost of treatment, as the diet is easily accessible. This dietary approach could significantly enhance the management of TMD symptoms.

Knowledge and awareness about temporomandibular disorder among dentists in India: Questionnaire study and review

AIM

Temporomandibular disorders (TMD) comprise ailments involving the jaw joint (temporomandibular joint) and its associated anatomical structures. The complexity involved in TMD is primarily due to its broad spectrum of conditions, clinical signs and symptoms variability, and multifactorial etiology. Considering the above, the present study was performed to help understand the prevailing knowledge and awareness of TMD among Indian dentists in the context of the new specialty "orofacial pain".

SETTINGS AND DESIGN

Questinnaire study and review.

MATERIALS AND METHODS

The questionnaire was distributed using a web-based portal nationwide among Indian dentists. Dentists were invited to participate, clearly stating that the intent and purpose of the questionnaire was to record the existing knowledge and awareness concerning temporomandibular disorders among Indian dentists. The questionnaire was segregated into three sections: pathogenesis, diagnosis, and management of TMDs. The questions were recorded using a Likert three-point scale (1=agree; 2=disagree; 3=not aware). 310 dentists participated in the survey, among which 105 were general dentists (BDS [Bachelor of Dental Surgery] graduates), and 205 were dentists with specialist training (MDS [Masters of Dental Surgery] graduates).

STATISTICAL ANALYSIS USED

The results obtained from the study participants was used to calculate the percentage and frequency, following which tabulations were made based on graduate type and clinical experience. The values obtained from all three sections were recorded, and the responses were analysed using Pearson's Chi-Square test with statistical significance kept at P < 0.05.

RESULTS

Results of the study disclosed that only 58.1% of general dentists and 46.8% of specialists were confident in handling temporomandibular disorder patients. Splint therapy was the preferred treatment modality for general dentists, whereas dentists with specialist training preferred occlusal rehabilitation.

CONCLUSION

The results of the current survey indicate that Indian dentists lack sufficient training in dental schools on all three sections and face difficulty diagnosing and treating TMDs.

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".

Clinical aspects of mastication myalgia-an overview

Mastication myalgia is the most common cause of non-odontogenic pain in the orofacial region and is often associated with a reduced quality of life. The purpose of this review is to provide an overview of the clinical aspects of myalgia based on available research. The review includes epidemiological, diagnostic, and etiological aspects. In addition, the potential risk factors related to the transition from acute to chronic myalgia are explored and treatment strategies are presented for its management. As a result, this review may increase clinical knowledge about mastication myalgia and clarify strategies regarding prevention, diagnostics, and management to improve prognosis and reduce patient suffering.

Analysis of Cervical Range of Motion in Subjects Affected by Temporomandibular Disorders: A Controlled Study

Background and Objectives: The aim of this study were to compare the cervical ROM data obtained from accelerometer exams between patients suffering from TMDs (study group) and healthy patients (control group). Material and Methods: A sample of 43 young adult subjects (23 control subjects and 20 TMD patients) were included in this study and analyzed with the accelerometer (Baiobit™, BTS, Garbagnate Milanese, Milan, Italy) to assess cervical ROM using a standardized protocol, including the following occlusal conditions: mandibular rest position, clenching, clenching with cotton rolls, maximal intercuspation, and mandibular position with cotton rolls. The cervical ROM was measured in degrees and expressed as the mean and standard deviation. Results: TMD patients showed a reduced cervical extension compared to control subjects in all the conditions, with statistically significant relevance. Regarding the other movements, the differences were not statistically or clinically significant. Conclusions: Based on the results of the present study, it can be observed that temporomandibular disorders are associated with a decreased cervical extension range, while the remaining components of ROM do not seem to be significantly associated. The use of accelerometers in ROM analysis could be helpful in improving interdisciplinary communication between dentists and physiotherapists.

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.

RA.DI.CA. Splint Therapy in the Management of Temporomandibular Joint Displacement without Reduction

BACKGROUND

The purpose of this study is to report clinical and instrumental changes after RA.DI.CA splint therapy for temporomandibular joint disc displacement without reduction.

METHODS

Subjects affected by disc dislocation without reduction were recruited between July 2020 and May 2022 based on inclusion and exclusion criteria and treated with RA.DI.CA. splints over a period of 6 months. Clinical data were collected at each phase of the study (T0, T1, T2). Magnetic resonance imaging and electrognathography data were recorded at the beginning (T0) and at the end (T2) of the study. ANOVA with post-hoc contrasts was performed to assess differences in outcome measures over time. The Wilcoxon test was used to evaluate changes in disc-condyle angle between before- and after-treatment MRI. A two-tailed value of p < 0.05 was regarded as significant.

METHODS

Ten patients completed the study. There were statistically significant differences over time for arthralgia, headache, neck pain, and mouth opening. Disc recapture and an improved quality of mandibular movement were recorded in 70% of subjects. The clinical and instrumental improvements are probably due to the orthopedic action of RA.DI.CA splint treatment, which allows for a greater degree of joint mobilization.

CONCLUSIONS

The purpose of this therapy is to recover the disc position if possible and achieve an adequate joint functional adaptation that avoids the progression of the structural damage and the recurrence of symptoms.

Effectiveness of Physical Therapy Interventions for Temporomandibular Disorders Associated with Tinnitus: A Systematic Review

Temporomandibular disorders (TMDs) refers to different clinical conditions affecting the temporomandibular joints, masticatory muscles, and adjacent structures. Although TMDs signs and symptoms (e.g., pain and limited mouth opening) are common, otological symptoms, such as tinnitus, might also be present. This study aims to summarize the evidence of the effectiveness of physical therapy interventions in individuals with TMDs associated with tinnitus. Randomized controlled trials investigating the effectiveness of physical therapy in individuals of both genders aged 18 or older with TMDs associated with tinnitus were included. The electronic search was performed in the following databases: MEDLINE, EMBASE, CINAHL, PEDro and CENTRAL. A total of four studies were included. All studies showed that physical therapy reduced the intensity of tinnitus, and two trials showed a decrease in the pain intensity caused by TMDs, an increase in the pressure pain thresholds in the masticatory muscles and an improvement of mandibular function. Two studies presented a low risk of bias. Despite a low certainty of the evidence, this review showed that physical therapy reduces the intensity or severity of tinnitus associated with TMDs. Results may support future research on the topic and evidence-based practice by recommending the best physical therapy approach for patients, clinicians, researchers, and health system managers.

Psychosocial factors associated with pain outcomes in patients with painful temporomandibular disorders and headaches

The objective of this study was to assess the association between psychosocial factors (in terms of anxiety, somatization, depression, and optimism) and pain (in terms of headache pain intensity and pain-related disability), in patients with a painful temporomandibular disorder (TMD) and one of the following headache types: migraine, tension-type headache (TTH), or headache attributed to TMD, corrected for the influence of bruxism. A retrospective study was conducted at an orofacial pain and dysfunction (OPD) clinic. Inclusion criteria were painful TMD, with migraine, TTH, and/or headache attributed to TMD. Linear regressions were performed to assess the influence of psychosocial variables on pain intensity and on pain-related disability, stratified per headache type. The regression models were corrected for bruxism and the presence of multiple headache types. A total of 323 patients (61% female; mean age 42.9, SD 14.4 years) were included. Headache pain intensity only had significant associations in TMD-pain patients with headache attributed to TMD, and anxiety showed the strongest relation (β = 0.353) with pain intensity. Pain-related disability was most strongly associated with depression in TMD-pain patients with TTH (β = 0.444), and with somatization in patients with headache attributed to TMD (β = 0.399). In conclusion, the influence of psychosocial factors on headache pain intensity and pain-related disability depends on the headache type presenting.

The Effect of Upper Cervical Mobilization/Manipulation on Temporomandibular Joint Pain, Maximal Mouth Opening, and Pressure Pain Thresholds: A Systematic Review and Meta-Analysis

Objective

To evaluate the efficacy of upper cervical joint mobilization and/or manipulation on reducing pain and improving maximal mouth opening (MMO) and pressure pain thresholds (PPTs) in adults with temporomandibular joint (TMJ) dysfunction compared with sham or other intervention.

Data Sources

MEDLINE, CINAHL, EMBASE, and Cochrane Library from inception to June 3, 2022, were searched.

Study Selection

Eight randomized controlled trials with 437 participants evaluating manual therapy (MT) vs sham and MT vs other intervention were included. Two reviewers independently extracted data and assessed risk of bias.

Data Extraction

Two independent reviewers extracted information about origin, number of study participants, eligibility criteria, type of intervention, and outcome measures.

Data Synthesis

Manual therapy was statistically significant in reducing pain compared with sham (mean difference [MD]: -1.93 points, 95% confidence interval [CI]: -3.61 to -0.24, P=.03), and other intervention (MD: -1.03 points, 95% CI: -1.73 to -0.33, P=.004), improved MMO compared with sham (MD: 2.11 mm, 95% CI: 0.26 to 3.96, P=.03), and other intervention (MD: 2.25 mm, 95% CI: 1.01 to 3.48, P<.001), but not statistically significant in improving PPT of masseter compared with sham (MD: 0.45 kg/cm2, 95% CI: -0.21 to 1.11, P=.18), and other intervention (MD: 0.42 kg/cm2, 95% CI: -0.19 to 1.03, P=.18), or the PPT of temporalis compared with sham (MD: 0.37 kg/cm2, 95% CI: -0.03 to 0.77, P=.07), and other intervention (MD: 0.43 kg/cm2, 95% CI: -0.60 to 1.45, P=.42).

Conclusion

There appears to be limited benefit of upper cervical spine MT on TMJ dysfunction, but definitive conclusions cannot be made because of heterogeneity and imprecision of treatment effects.

Headache and orofacial pain: A traffic-light prognosis-based management approach for the musculoskeletal practice

Introduction

Headache (HA) is one of the most prevalent disabling conditions worldwide and is classified as either primary or secondary. Orofacial pain (OFP) is a frequent pain perceived in the face and/or the oral cavity and is generally distinct from a headache, according to anatomical definitions. Based on the up-to-date classification of the International Headache Society, out of more than 300 specific types of HA only two are directly attributed to the musculoskeletal system: The cervicogenic HA and HA attributed to temporomandibular disorders. Because patients with HA and/or OFP frequently seek help in the musculoskeletal practice, a clear and tailored prognosis-based classification system is required to achieve better clinical outcomes.

Purpose

The aim of perspective article is to suggest a practical traffic-light prognosis-based classification system to improve the management of patients with HA and/or OFP in the musculoskeletal practice. This classification system is based on the best available scientific knowledge based on the unique set-up and clinical reasoning process of musculoskeletal practitioners.

Implications

Implementation of this traffic-light classification system will improve clinical outcomes by helping practitioners invest their time in treating patients with significant involvement of the musculoskeletal system in their clinical presentation and avoid treating patients that are not likely to respond to a musculoskeletal based intervention. Furthermore, this framework incorporates medical screening for dangerous medical conditions, and profiling the psychosocial aspects of each patient; thus follows the biopsychosocial rehabilitation paradigm.

Chronic craniomandibular pain after craniotomy: A long-term clinical study

OBJECTIVE

Chronic craniomandibular/cervical pain and temporomandibular disorders have not been studied in patients who had a craniotomy several years previously. The aim of the current clinical work was to address these issues.

METHODS

A total group of 150 ambulant patients who had a previous craniotomy was subclassified according to whether or not the temporalis muscle was manipulated.

RESULTS

The average incidence of multiple subsite regional head and neck pain was 69.3% a number of years after a craniotomy. Evidence of internal derangement of the temporomandibular joint was significantly higher in the group that required manipulation of the temporalis muscle during the procedure.

CONCLUSION

The pattern of chronic craniomandibular/cervical pain experienced years after a craniotomy supports the brain neuromatrix theory of pain.

Postural Disharmony Causing Myofacial Pain: A Case Report and Review of Literature of the Treatment

Myofacial pain, a chronic painful condition of muscle origin, has numerous precipitating factors, if undiagnosed or left untreated could lead to compromised function and poor quality of life. In this case report, a female patient giving a history of 10 years of pain in the head and neck region was eventually diagnosed with myofacial pain secondary to bowing posture. The patient was successfully treated with combination of treatment modalities (TENS therapy, exercises, occlusal splint, etc.), which resulted in relief from chronic pain and improvement in quality of life.

Pain Management and Rehabilitation for Central Sensitization in Temporomandibular Disorders: A Comprehensive Review

Temporomandibular disorders (TMD) are a group of musculoskeletal diseases affecting masticatory muscles and temporomandibular joints (TMJ). In this context, the chronic TMD could be considered as a condition with chronic primary orofacial pain, presenting as myofascial TMD pain or TMJ arthralgia. In this context, myogenous TMD may present overlapping features with other disorders, such as fibromyalgia and primary headaches, characterized by chronic primary pain related to dysfunction of the central nervous system (CNS), probably through the central sensitization. This phenomenon could be defined as an amplified response of the CNS to sensory stimuli and peripheral nociceptive, characterized by hyperexcitability in the dorsal horn neurons in the spinal cord, which ascend through the spinothalamic tract. The main objectives of the management of TMD patients are: decreasing pain, increasing TMJ function, and reducing the reflex masticatory muscle spasm/pain. The first-line treatments are physical therapy, pharmacological drugs, occlusal splints, laser therapy, extracorporeal shockwave therapy, transcutaneous electrical nerve stimulation, and oxygen-ozone therapy. Although all these therapeutic approaches were shown to have a positive impact on the central sensitization of TMD pain, there is still no agreement on this topic in the scientific literature. Thus, in this comprehensive review, we aimed at evaluating the evidence on pain management and rehabilitation for the central sensitization in TMD patients.

The association between myofascial orofacial pain with and without referral and widespread pain

OBJECTIVES

Pain referral on palpation has been suggested to be a clinical sign of central sensitization potentially associated with widespread pain conditions. Our aim was to evaluate if myofascial pain with referral is a better predictor for widespread pain when compared to no pain or local myofascial pain.

MATERIALS AND METHODS

Individuals at the Public Dental services in Västerbotten, Sweden, were randomly invited based on their answers to three screening questions for temporomandibular disorders (TMD). In total, 300 individuals (202 women, 20-69 yrs) were recruited, and examined according to the Diagnostic Criteria for TMD (DC/TMD) after completion of a body pain drawing. Widespread pain was considered present when seven or more pain sites were reported on the widespread pain index. A binary logistic regression model, adjusted for the effect of age and gender were used to evaluate the association between myofascial orofacial pain and widespread pain.

RESULTS

Widespread pain was reported by 31.3% of the study sample. There was a 57.3% overlap with myofascial pain. Widespread pain was associated to myofascial orofacial pain with and myofascial orofacial pain (OR 4.83 95% CI 2.62-9.05 and OR 11.62 95% CI 5.18-27.88, respectively).

CONCLUSION

These findings reinforce the existing knowledge on the overlap between painful TMD and other chronic pain conditions.

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.

A novel artificial neural network for the diagnosis of orofacial pain and temporomandibular disorders

BACKGROUND

Temporomandibular disorders (TMD) and orofacial pain are highly prevalent. This prevalence can be compared to that of leading non-communicable diseases (NCDs). However, it is surprising to still find a high degree of controversy regarding its diagnosis and management. Patients usually experience treatment delays, missed diagnoses, and receive unnecessary therapies. New artificial intelligence algorithms have helped diagnose numerous diseases. Nevertheless, no studies have focused on the use of artificial intelligence to diagnose these conditions.

OBJECTIVES

This study aimed to develop and test the performance of a novel neural network (multilayer perceptron) with diagnostic capabilities in orofacial pain and TMD, including some types of referred pain.

METHODS

A multilayer perceptron (MLP) was developed with one input layer, five hidden layers, and one output layer. It was trained using backpropagation algorithms. Several categories of orofacial pain and TMD clinical cases were presented to 12 general dental clinicians, and their diagnoses were contrasted to those provided by the artificial intelligence neural network.

RESULTS

Overall, the diagnostic accuracy of the artificial intelligence was superior to that of the general dental clinicians (p = .0072). This was more evident in the clinical cases involving non-dental and referred orofacial pains (e.g. neuropathic pain, referred cardiac pain, neurovascular pain).

CONCLUSIONS

This study showed, for the first time, that an artificial neural network can help medical and general dental clinicians diagnose several types of orofacial pain and dysfunction, including TMD, neuropathic, neurovascular, and referred cardiac pain. In some cases, the MLP appears to have a life-saving role.

Biological and Molecular Docking Evaluation of a Benzylisothiocyanate Semisynthetic Derivative From Moringa oleifera in a Pre-clinical Study of Temporomandibular Joint Pain

Objective

Moringa oleifera possesses multiple biological effects and the 4-[(4′-O-acetyl-α-L- rhamnosyloxy) benzyl] isothiocyanate accounts for them. Based on the original isothiocyanate molecule we obtained a semisynthetic derivative, named 4-[(2′,3′,4′-O-triacetyl-α-L-rhamnosyloxy) N-benzyl] hydrazine carbothioamide (MC-H) which was safe and effective in a temporomandibular joint (TMJ) inflammatory hypernociception in rats. Therefore, considering that there is still a gap in the knowledge concerning the mechanisms of action through which the MC-H effects are mediated, this study aimed to investigate the involvement of the adhesion molecules (ICAM-1, CD55), the pathways heme oxygenase-1 (HO-1) and NO/cGMP/PKG/K⁺_ATP, and the central opioid receptors in the efficacy of the MC-H in a pre-clinical study of TMJ pain.

Methods

Molecular docking studies were performed to test the binding performance of MC-H against the ten targets of interest (ICAM-1, CD55, HO-1, iNOS, soluble cGMP, cGMP-dependent protein kinase (PKG), K⁺_ATP channel, mu (μ), kappa (κ), and delta (δ) opioid receptors). In in vivo studies, male Wistar rats were treated with MC-H 1 μg/kg before TMJ formalin injection and nociception was evaluated. Periarticular tissues were removed to assess ICAM-1 and CD55 protein levels by Western blotting. To investigate the role of HO-1 and NO/cGMP/PKG/K⁺_ATP pathways, the inhibitors ZnPP-IX, aminoguanidine, ODQ, KT5823, or glibenclamide were used. To study the involvement of opioid receptors, rats were pre-treated (15 min) with an intrathecal injection of non-selective inhibitor naloxone or with CTOP, naltrindole, or norbinaltorphimine.

Results

All interactions presented acceptable binding energy values (below −6.0 kcal/mol) which suggest MC-H might strongly bind to its molecular targets. MC-H reduced the protein levels of ICAM-1 and CD55 in periarticular tissues. ZnPP-IX, naloxone, CTOP, and naltrindole reversed the antinociceptive effect of MC-H.

Conclusion

MC-H demonstrated antinociceptive and anti-inflammatory effects peripherally by the activation of the HO-1 pathway, as well as through inhibition of the protein levels of adhesion molecules, and centrally by μ and δ opioid receptors.

The detrimental impact of temporomandibular disorders (mis)beliefs and possible strategies to overcome

AIM

This topical review presents common patients' misbeliefs about temporomandibular disorders (TMD) and discusses their possible impact on the diagnosis, treatment and prognosis. We also discussed the possible influence of the beliefs and behaviors of health care providers on the beliefs of patients with TMD and present possible strategies to overcome the negative impacts of such misbeliefs.

METHODS

This topical review was based on a non-systematic search for studies about the beliefs of patients and professionals about TMD in PubMed and Embase.

RESULTS

Patients' beliefs can negatively impact the diagnosis, treatment, and prognosis of TMD. These beliefs can be modulated by several factors such as culture, psychosocial aspects, gender, level of knowledge, and previous experiences. Moreover, primary health care professionals, including dentists, may lack sufficient experience and skills regarding TMD diagnosis and treatment. Misbeliefs of the health care professionals can be based on outdated evidence that is not supported by rigorous methodological investigations. Education and dissemination of knowledge to patients and the general population are effective for prevention, promotion of health and disruption of the cycle of misinformation and dissemination of misbeliefs.

CONCLUSION

The lack of basic information about TMD and the dissemination of mistaken and outdated concepts may delay the diagnosis, hinder the treatment, and consequently increase the risk of worsening the condition. Education is key to overcome TMD misbeliefs.

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

BACKGROUND

This systematic review was designed to evaluate the presence of comorbid conditions among patients with temporomandibular disorders (TMDs).

TYPES OF STUDIES REVIEWED

The authors reviewed studies that reported the prevalence or incidence of chronic pain conditions or psychiatric disorders (anxiety, mood, personality disorders) among patients with any type of TMD. The authors calculated sample size-weighted prevalence estimates when data were reported in 2 or more studies for the same comorbid condition.

RESULTS

A total of 9 prevalence studies and no incidence studies were eligible for review; 8 of the studies examined chronic pain comorbidities. Weighted estimates showed high prevalence of pain comorbidities across studies, including current chronic back pain (66%), myofascial syndrome (50%), chronic stomach pain (50%), chronic migraine headache (40%), irritable bowel syndrome (19%), and fibromyalgia (14%). A single study examined psychiatric disorders and found that current depression was the most prevalent disorder identified (17.5%).

CONCLUSIONS AND PRACTICAL IMPLICATIONS

There is a high prevalence of comorbid chronic pain conditions among patients with TMDs, with more than 50% of patients reporting chronic back pain, myofascial syndrome, and chronic stomach pain. Psychiatric disorders among patients with different types of TMDs were studied less commonly in this pain population. Knowledge of the distribution of these and other comorbid disease conditions among patients with different types of TMDs can help dentists and other health care providers to identify personalized treatment strategies, including the coordination of care across medical specialties.

Hemicrania continua secondary to neurogenic paravertebral tumor- a case report

OBJECTIVES

Hemicrania continua (HC) is one of the trigeminal autonomic cephalalgias (TAC), where sympathetic dysfunction and autonomic dysfunction resulting in parasympathetic over activation with some evidence of sympathetic inhibition have been suggested as probable causes. However, cases of hemicrania continua secondary to sympathetic dysfunction due to neurogenic paravertebral tumor impinging on the sympathetic chain has not been previously reported. In this case, the probability of the sympathetic dysfunction was more likely based on the clinical features and management.

CASE PRESENTATION

A 23-year-old female presented with a chief complaint of right unilateral pain in the retro-bulbar, head and facial region for the past three years. An initial MRI of the brain was negative, whereas an MRI of the spine was advised to rule out a cervicogenic origin of the pain. The MRI revealed a well-defined mass lesion within right paravertebral region at T3 indicative of a neurogenic tumor. The patient was diagnosed with probable hemicrania continua secondary to neurogenic tumor impinging on adjacent sympathetic chain. A trial of indomethacin 75 mg/day was advised, which provided complete relief of the headache. The patient was referred to a neurologist for management of the neurogenic tumor.

CONCLUSIONS

Headache disorders may be secondary to pathologies and comprehensive evaluation and accurate diagnosis are essential. Knowledge of neuroanatomy is paramount to understand and explain underlying pathophysiological mechanisms. Multidisciplinary management is essential in complex orofacial cases.

Predicting the number of physical therapy visits and patient satisfaction in individuals with temporomandibular disorder: A cohort study

BACKGROUND

Temporomandibular disorders (TMD) can be challenging to manage for clinicians and patients alike. It is unclear which factors are associated with prolonging conservative care and patient dissatisfaction with treatment outcomes.

OBJECTIVES

To examine factors collected during a physical therapy (PT) evaluation in a cohort of individuals with TMD to determine factors associated with an increased number of PT visits and reduced patient satisfaction.

METHODS

Records of 511 patients referred to PT over 18 months were reviewed to extract 27 variables to develop a predictive model. Outcomes were patient satisfaction following PT and number of PT visits. Linear and zero inflated negative binomial regressions were used, and a multivariate regression model was built for both outcomes.

RESULTS

Two factors were associated with both lower patient satisfaction and an increased number of PT visits: higher patient rated functional neck disability and a greater number of healthcare professionals seen. Other factors associated with patient satisfaction were duration of symptoms, subluxation, and referral from an oral surgeon. Only patient rated functional neck disability score was a significant predictive factor in the multivariate model. Factors associated with number of PT visits were gender, educational level, time between initial visit and discharge, number of pain areas, bruxism, biopsychosocial factors, dizziness, pain rating, and presence of neck pain. In the multivariate model, gender, number of healthcare professionals seen, and resting pain rating were significant predictors of number of PT visits.

CONCLUSION

Considering key factors on initial evaluation, specifically functional neck disability and the number of prior healthcare professionals seen before starting PT, can help to predict a higher number of PT visits and reduced patient satisfaction with outcomes.

Presence of widespread pain predicts comorbidities and treatment response in temporomandibular disorders patients

OBJECTIVES

Investigate the presence of widespread pain in a well-defined TMD group and analyze its interrelationship with various comorbidities. Also, longitudinally seek the difference in treatment response according to the presence of widespread pain.

SUBJECTS AND METHODS

The observational study involved 45 female TMD patients in their 20s. Patients were grouped into localized and widespread pain groups based on the widespread pain index (WPI ≥ 4). Clinical characteristics and levels of comorbidities were analyzed through physical examination and validated questionnaires. Differences between the groups and the power of pre-treatment WPI in predicting pre-treatment comorbidities and post-treatment pain level improvement were statistically analyzed.

RESULTS

Patients with widespread pain showed higher somatization and anxiety levels. SF-36 scores were significantly lower and more patients complained of gastrointestinal symptoms. Conventional treatment significantly reduced pain intensity in both groups but less in the widespread pain group. WPI showed significant chances to predict patients showing improvement in pain levels with treatment with a cutoff value of 4. WPI was also effective in differentiating patients that showed a higher level of somatization.

CONCLUSION

Widespread pain index could be effectively applied in differentiating those with a higher level of psychological distress and predicting TMD treatment response with further investigations into its reliability.

Comorbid Conditions in Temporomandibular Disorders Myalgia and Myofascial Pain Compared to Fibromyalgia

The impact of comorbidities in fibromyalgia (FM) and temporomandibular disorders (TMD) have been well documented, but whether TMD sub-diagnoses myalgia (MYA) and myofascial pain with referral (MFP) differ regarding comorbidity is unclear. We aimed to elucidate this by studying the presence and associations of comorbidities in FM, MFP and MYA. An extended version of the Diagnostic Criteria for TMD axis II questionnaire was used to examine demographics, pain and comorbidities in 81 patients with FM, 80 with MYA, and 81 with MFP. Patients with MFP and FM reported a higher percentage of irritable bowel syndrome (IBS), depression, anxiety, somatic symptoms, perceived stress, and insomnia compared to MYA. Patients with FM had more IBS, depression, and somatic symptom disorder versus MFP. After adjusting for confounding variables, participants with anxiety, somatic symptoms disorder, pain catastrophizing, and perceived stress, as well as a greater number of comorbidities, were more likely to have MFP than MYA, whereas FM participants were more associated with IBS, somatic symptoms and insomnia compared to MFP. The number of comorbidities was significantly associated with widespread pain but not pain duration, body mass index or being on sick leave. In conclusion, patients with MFP were more similar to those with FM regarding comorbidity and should be differentiated from MYA in clinical settings and pain management.

Physical therapist guided active intervention of chronic temporomandibular disorder presenting as ear pain: A case report

This case report describes the successful physical therapy management of a 40-year-old female who presented with left ear pain referred from the temporomandibular joint. Diagnosis was primarily based on clinical examination findings and ruling out of red flags. Guidance was given on active self-care approaches consisting of pain neuroscience education designed with individualized pain curriculum, exercise therapy, manual therapy, and breathing exercises for a period of  sixweeks. Clinically meaningful improvements were obtained in the outcome measures of Numeric Pain Rating Scale (NPRS), Patient-Specific Functional Scale (PSFS), and Global Rating of Change (GROC) scale and progress in Pain-Self Efficacy Questionnaire (PSEQ) and Tampa Scale for Kinesiophobia (TSK) scores. Positive changes were achieved with functional activities (chewing, eating, yawing, brushing teeth and physical intimacy), and the patient was pain-free on discharge, which was maintained at a six-month follow-up.

Animal Models of Temporomandibular Disorder

Temporomandibular disorders (TMD) are a group of diseases in the oral and maxillofacial region that can manifest as acute or chronic persistent pain, affecting millions of people worldwide. Although hundreds of studies have explored mechanisms and treatments underlying TMD, multiple pathogenic factors and diverse clinical manifestations make it still poorly managed. Appropriate animal models are helpful to study the pathogenesis of TMD and explore effective treatment measures. At present, due to the high cost of obtaining large animals, rodents and rabbits are often used to prepare TMD animal models. Over the past decade, various animal models have been intensively developed to understand neurobiological and molecular mechanisms of TMD, and seek effective treatments. Although these models cannot carry out all clinical features, they are valuable in revealing the mechanisms of TMD and creating curative access. Currently, there are multitudinous animal models of TMD research. They can be constructed in different means and summarized into four ways according to the various causes and symptoms, including chemical induction (intra-articular injection of ovalbumin, collagenase, formalin, vascular endothelial growth factor, intramuscular injection of complete Freund’s adjuvant, etc.), mechanical stress stimulation (passive mouth opening, change of chewing load), surgical operation (partial disc resection, joint disc perforation) and psychological stress induction. Here, we summarize and discuss different approaches of animal models for determining neurophysiological and mechanical mechanisms of TMD and assess their advantages and limitations, respectively.

Association of cervical spine signs and symptoms with temporomandibular disorders in adults: a systematic review protocol

OBJECTIVE

The objective of this systematic review is to assess the evidence of association of cervical spine signs and symptoms with temporomandibular disorders (TMD). This will help to lend credence to mechanisms supporting the association in order to improve care strategies for this condition.

INTRODUCTION

The association of cervical spine impairments (in relation to neck posture, cervical spine mobility, muscle tenderness, muscle activity, and neck disability) with TMD has been widely discussed in the literature. Clarification of this relationship is important for health professionals to better assess and treat TMD.

INCLUSION CRITERIA

Eligible studies will include participants aged 18 years and over, with a diagnosis of TMD from the Research and Diagnostic Criteria for Temporomandibular Disorders or a revised version. Exclusion criteria will be participants with previous temporomandibular joint surgery, history of trauma or fracture in the temporomandibular joint or the craniomandibular system; serious comorbid conditions such as cancer, rheumatic disease, and neurological problems; primary cervical spine disorders such as disc herniation or spinal degenerative changes; or systemic disease such as ankylosing spondylitis.

METHODS

The search for articles will be conducted in the databases PubMed, PEDro, CINAHL, Web of Science, and Embase, without language or time restrictions. Two independent reviewers will review the title, abstract, and full texts of identified studies; select studies against the inclusion criteria; assess the methodological quality of eligible studies using critical appraisal tools; and perform data extraction. Relevant quantitative data will be pooled with statistical meta-analysis, when possible.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO CRD42019123698.

Long-term evaluation of temporomandibular disorders in association with cytokine and autoantibody status in young women

Temporomandibular disorders (TMD) is a chronic pain disease affecting 4-60% of general population. Its suggested etiology includes mechanical overloading to related structures, psychosocial factors, and genetic vulnerability. However, its pathogenesis is yet to be fully understood, especially in cases with a higher level of pain and more associated comorbidities. Recently chronic systemic inflammation and possible autoimmunity has been indicated in several pain conditions as the underlying mechanism of chronicity but this aspect has not been rigorously investigated in TMD. This article focuses on analyzing the levels of cytokines, chemokines, autoantibodies and nonspecific inflammatory markers and comparing their levels according to pain severity and duration in 66 female TMD patients in their 20 s and investigating their association with clinical indices of TMD and comorbidities. The high pain disability group showed decreased range of jaw function and more pain on palpation of capsule areas compared to the low pain disability group. Comorbidities such as anxiety and sleep disturbance were also significantly more prevalent. The level of IL-8 and IgG were significantly higher in the high pain disability group. IL-2, -8, -13, IFN- γ, RANTES, PGE2, and thrombopoietin levels showed a significant effect on indices reflecting jaw function, generalized pain intensity, and health related quality of life. Such results imply that longer pain duration and higher pain intensity is associated with higher levels of systemic inflammation suggesting the possible role of immunologic disturbance as an underlying factor of chronic TMD pain and warranting further investigation for its consideration in diagnosis and treatment.

Effects of physical therapy for temporomandibular disorders on headache pain intensity: A systematic review

BACKGROUND

Physical therapy is regarded an effective treatment for temporomandibular disorders (TMD). Patients with TMD often report concomitant headache. There is, however, no overview of the effect of physical therapy for TMD on concomitant headache complaints.

OBJECTIVES

The aim of this study is to systematically evaluate the literature on the effectiveness of physical therapy on concomitant headache pain intensity in patients with TMD.

DATA SOURCES

PubMed, Cochrane and PEDro were searched.

STUDY ELIGIBILITY CRITERIA

Randomized or controlled clinical trials studying physical therapy interventions were included.

PARTICIPANTS

Patients with TMD and headache.

APPRAISAL

The Cochrane risk of bias tool was used to assess risk of bias.

SYNTHESIS METHODS

Individual and pooled between-group effect sizes were calculated according to the standardized mean difference (SMD) and the quality of the evidence was rated using the GRADE approach.

RESULTS

and manual therapy on both orofacial region and cervical spine. There is a very low level of certainty that TMD-treatment is effective on headache pain intensity, downgraded by high risk of bias, inconsistency and imprecision.

LIMITATIONS

The methodological quality of most included articles was poor, and the interventions included were very different.

CONCLUSIONS

Physical therapy interventions presented small effect on reducing headache pain intensity on subjects with TMD, with low level of certainty. More studies of higher methodological quality are needed so better conclusions could be taken.

Prevalence of temporomandibular disorder in adult patients with chronic pain

Objectives

Chronic pain patients often suffer in multiple locations. In health care, examinations of bodily pain usually do not include questions about temporomandibular disorders (TMD); hence TMD symptoms and potential comorbidities are not regularly assessed. Therefore, the primary aim was to evaluate the prevalence of TMD in patients referred to a pain rehabilitation clinic, and the secondary aim was to evaluate possible factors associated with TMD symptoms.

Methods

Consecutive chronic pain patients referred to the Pain Rehabilitation Clinic at the Umeå University Hospital in Sweden were included. TMD symptoms were assessed using three valid screening questions – 3Q/TMD. Pain sites, emotional distress, kinesiophobia, and demographics were obtained from the Swedish Quality Registry for Pain Rehabilitation.

Results

In total, 188 (144 women) chronic pain patients (mean age 41.8 years) were included. Of these, 123 (96 women) answered affirmatively to at least one of the 3Q/TMD. The relative risk of TMD symptoms among the patients with chronic pain, in comparison to the general population, was 7.1 (95% CI 5.9–8.4). Age was the only independent variable associated with TMD among the patients (p = 0.018).

Conclusions

The prevalence of TMD symptoms was higher in a chronic pain population compared to the general population. The 3Q/TMD questionnaire could be a suitable screening tool at pain rehabilitation clinics to identify patients for further examination of involvement of pain in the trigeminal region. Our results reinforce the clinical importance of paying attention to concurrent widespread pain and local TMD symptoms.

Self-Perceived Dentists' Knowledge of Temporomandibular Disorders in Krakow: A Pilot Study

Introduction

The most common nondental orofacial pain conditions are temporomandibular disorders (TMDs). TMD basic examination and clinical management are included in a curriculum of each dentistry programme taught in Poland, but it is not clear how the dentists cope with diagnosis and possible treatment in their routine dental practices. The objective of the present study was to assess a level of self-perceived knowledge of TMD amongst dentists in Poland. Materials and methods. The participants, of whom all studied and graduated from a Polish university, were randomly selected from dental offices in Krakow (Poland). The selected dentists were administered an anonymous questionnaire, which contained questions measuring self-assessment of knowledge of TMD diagnosis and therapy and assessing knowledge of ethology and TMD symptoms.

Results

Only 6.5% of the participants identified their TMD knowledge as very good, 32.3% assessed it as good, 39.3% thought it was sufficient, 20.4% as insufficient, and 1.49% considered it as poor. 9.4% of all participants have attempted to diagnose and treat TMD patients very often, 26.4% declared performing it often, 45.8% rarely, and 18.4% had never made such an attempt. There was a significant relationship between the dentists' knowledge and their attempts at diagnosing and treating TMD patients (p < 0.05).

Conclusion

The level of TMD knowledge amongst the Polish dentists is still insufficient. Raising its level would considerably help the dentists to refer their patients to right specialists for a diagnosis and TMD treatment and/or interdisciplinary management of TMD patients.

Absence of joint pain identifies high levels of sleep masticatory muscle activity in myofascial temporomandibular disorder

Although the development of reliable diagnostic criteria for temporomandibular disorders (TMDs) has operationalised identification of a subgroup with myofascial pain (mTMD), causal mechanisms remain elusive. This study examines masticatory muscle activity (MMA) in more homogenous research subgroups of mTMD. Data from an existing case-control study of women were used to subcategorise mTMD cases based on joint pain with palpation to isolate muscle-only pain (M-pain) vs muscle and joint pain (MJ-pain). Differences in laboratory indicators of MMA, specifically research diagnostic criteria for sleep bruxism (SB) and high background EMG activity, and other clinical and sociodemographic indicators were examined between groups. Compared to controls, the MJ-pain subgroup did not show elevated background EMG or sleep bruxism. In contrast, the M-pain subgroup showed significantly higher background EMG and a trend towards elevated prevalence of sleep bruxism. These results may explain why it has been difficult for studies of SB in mixed TMD and even mTMD samples to find a consistent positive association, since a positive association may be limited to mTMD without joint pain. The subcategorising of mTMD based on joint pain with palpation (ie M-pain, MJ-pain) appears to reveal subgroups with relatively high and low sleep masticatory muscle-specific activity. Findings need replication in a larger study with updated mTMD diagnostic criteria, but may prove useful for understanding mechanism of pain maintenance in mTMD with and without joint pain.

Temporomandibular disorders, pain in the neck and shoulder area, and headache among musicians

Background

Uncertainties still exist about the role of playing musical instruments on the report of musculoskeletal complaints and headache.

Objectives

To evaluate the prevalence of and risk indicators for symptoms of temporomandibular disorders, pain in the neck or shoulder, and headache among musicians.

Methods

A questionnaire was distributed among 50 Dutch music ensembles.

Results

The questionnaire was completed by 1470 musicians (response rate 77.0%). Of these, 371 musicians were categorised as woodwind players, 300 as brass players, 276 as upper strings players, 306 as vocalists and 208 as controls; nine musicians had not noted their main instrument. The mean age was 41.6 years (standard deviation [SD] 17.2), and 46.5% were male. Irrespective of instrumentalist group, 18.3% of the musicians reported TMD pain, 52.5% reported pain in the neck and shoulder area, and 42.5% reported headache. Of the functional complaints, 18.3% of the musicians reported TMJ sounds, whereas a jaw lock or catch on opening or on closing was reported by 7.1% and 2.4%, respectively. TMD pain was associated with playing a woodwind instrument, whereas pain in the neck and shoulder was associated with playing the violin or viola. For each complaint, oral behaviours were found as risk indicator, supplemented by specific risk indicators for the various complaints.

Conclusions

The current finding that pain‐related symptoms varied widely between instrumentalist groups seems to reflect the impact of different instrument playing techniques. Playing a musical instrument appears not the primary aetiologic factor in precipitating a functional temporomandibular joint problem.

TMJ Dysfunctions Systemic Implications and Postural Assessments: A Review of Recent Literature

Cases of correlations between posture and the temporomandibular joint have long been reported in the literature. In particular, occlusal anomalies, and therefore malocclusion, could have negative implications for the spine. The objective of this study was to review the literature and bring to light any correlations between temporomandibular joints (TMJ) and posturology. The literature search was conducted in the PubMed and Embase scientific search engines with the aim of obtaining the most possible results in the initial search, the number of results initially obtained was 263. Subsequently, the inclusion and exclusion criteria were reduced first to 83 and subsequently to manual analysis of the articles, those included remained only 11. The results show a correlation between anomalies of the TMJ and dysfunctions of the vertebral column. Not all the articles considered are in agreement with each other regarding epidemiological data, but surely this study can represent an important starting point for a much more careful evaluation of the dental patient and at the same time for the request for counseling by a dentist in case of postural abnormalities.

Preclinical Signs of a Temporomandibular Disorder in Female Patients With Episodic Cervicogenic Headache Versus Asymptomatic Controls: A Cross-Sectional Study

BACKGROUND

The International Classification of Headache Disorders, 3rd Edition, accepted "headache attributed to temporomandibular disorders" as a valid headache. The neurophysiologic interplay between cervical structures and the temporomandibular joint, however, might also suggest that a temporomandibular disorder could develop in patients with cervicogenic headache.

OBJECTIVE

To compare the presence of preclinical temporomandibular signs between female patients with episodic cervicogenic headache and a control group.

DESIGN

Case-controlled cross-sectional design.

SETTING

Institutional setting: Hasselt University.

PARTICIPANTS

Twenty-two women (mean age ± SD: 20.7 ± 2.5 years) with episodic cervicogenic headache, without temporomandibular signs and 22 matched (gender, age, level of education, occupation) asymptomatic controls (21 ± 2.3 years).

METHODS

(Un)assisted temporomandibular range of motion, pressure pain thresholds, painful palpations were examined and the level of perceived stress was measured.

MAIN OUTCOME MEASUREMENTS

Temporomandibular range of motion (mm), pressure pain thresholds (kPa/cm²), painful palpations (yes/no), and level of perceived stress (Perceived Stress Scale).

RESULTS

Maximal mouth-opening was significantly smaller in the headache group (P <.05; effect size [ES] -0.45). Palpation of the masseter resulted in significantly more positive pain responses in the headache group at the left (P = .009; ES ∞) and right (P = .002;ES 17.5) origin, left (P = .004; ES 14.54) and right (P = .03; ES 5.71) body and left (P < .001; ES 12) insertion. Significantly lower pressure pain thresholds on the left and right anterior (P = .03; ES -0.33 resp. P = .02; ES -0.35), central (P = .003; ES 1.02 resp. P = .02; ES 0.79) and right posterior (P = .03; ES 0.62) temporalis and right tibialis anterior (P = .03; ES -0.33) were measured in the headache group. The level of perceived stress was significantly higher (P = .02) in the headache group.

CONCLUSIONS

Patients with episodic cervicogenic headache present with signs of a preclinical temporomandibular disorder and sensitization. The smaller range of motion, lower pressure pain thresholds, and higher levels of stress accentuate the multidimensionality of the problem.

LEVEL OF EVIDENCE

IV.

Anatomical selectivity in overlap of chronic facial and bodily pain

Supplemental Digital Content is Available in the Text.

Background:

Chronic facial pain often overlaps with pain experienced elsewhere in the body, although previous studies have focused on a few, selected pain conditions when assessing the degree of overlap.

Aim:

To quantify the degree of overlap between facial pain and pain reported at multiple locations throughout the body.

Methods:

Data were from a case–control study of US adults participating in the Orofacial Pain: Prospective Evaluation and Risk Assessment (OPPERA) project. They were interviewed to determine the presence of chronic facial pain (n = 424 cases) or its absence (n = 912 controls). A mailed questionnaire with a body drawing asked about pain at other locations. Odds ratios (ORs) and 95% confidence limits (95% CLs) quantified the degree of overlap between facial pain and pain at other locations. For replication, cross-sectional data were analyzed from the UK Biobank study (n = 459,604 participants) and the US National Health Interview Survey (n = 27,731 participants).

Results:

In univariate analysis, facial pain had greatest overlap with headache (OR = 14.2, 95% CL = 9.7–20.8) followed by neck pain (OR = 8.5, 95% CL = 6.5–11.0), whereas overlap decreased substantially (ORs of 4.4 or less) for pain at successively remote locations below the neck. The same anatomically based ranking of ORs persisted in multivariable analysis that adjusted for demographics and risk factors for facial pain. Findings were replicated in the UK Biobank study and the US National Health Interview Survey. The observed anatomical selectivity in the degree of overlap could be a consequence of neurosensory and/or affective processes that differentially amplify pain according to its location.

Differences between palpation and static/dynamic tests to diagnose painful temporomandibular disorders in patients with Lyme disease

OBJECTIVES

The aim was to determine the frequency of Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD)-based pain diagnoses and dynamic/static tests-based pain diagnoses, and to assess the agreement of palpation tests with static/dynamic tests.

MATERIALS AND METHODS

Eighty-six (N = 86) adult patients with Lyme disease (mean age 57.0 ± 14.3 years; male/female ratio was 42/44) were examined according to techniques described in the RDC/TMD. Additionally, dynamic/static tests were performed. For RDC/TMD-based pain diagnoses and dynamic/static tests-based pain diagnoses, descriptive frequencies were calculated. Differences between the frequency of palpation-based diagnoses and of dynamic/static-based diagnoses as well as the agreement between pain diagnoses established with the two diagnostic approaches were assessed.

RESULTS

RDC/TMD-based pain diagnoses were made in 61 patients for myofascial pain and in 11 patients for arthralgia and/or osteoarthritis. Based on dynamic/static tests, mainly myogenous pain was diagnosed in 6 patients, and a mainly arthrogenous pain in 5. The agreement of palpation tests with static/dynamic tests in Lyme disease population was poor.

CONCLUSION

A high prevalence of TMD symptoms was found in patients with Lyme disease. The results suggest that using palpation tests alone could overestimate primary TMDs when comorbid conditions are present.

CLINICAL RELEVANCE

Dynamic/static tests should be used as part of the routine TMD assessment. In case of Lyme disease as the actual cause of the facial pain, while the dentist might be suspecting TMD when dynamic/static TMD tests are negative, referral to an appropriate specialist for the diagnosis and treatment of Lyme disease needs to be made.

Seeking treatment for temporomandibular disorders: What patients can expect from non-dental health care providers

The dental profession has long been the primary source for clinical management of patients with temporomandibular disorders (TMDs). However, patients with a facial pain problem may seek diagnosis and/or treatment from other health care providers. These providers may be physicians or other professional-level practitioners, or they could be members of various allied groups, such as physical therapists or occupational therapists. However, little has been written about what patients might experience if they seek care outside of the dental profession. This article reports the results of an Internet survey of non-dental professionaland allied health care professionals to learn what they might offer to patients who may be seeking treatment for TMDs. The official organizational websites for all groups, as well as the websites of individual practitioners in each group, were reviewed. Most of the official websites had little or no information about TMDs, but some members of every group surveyed were offering to treat TMDs in their offices. The variety of treatments being offered went far beyond the boundaries of appropriate TMD management in the 21st century. These results are presented with a critical discussion of each concept or practice, as well as advice for both dentists and patients to deal with this situation.

Musculoskeletal Disorders

Temporomandibular disorder (TMD), a type of musculoskeletal pain, is a main cause of pain in the orofacial region. It involves the masticatory muscles, temporomandibular joints (TMJs), and associated structures. The most common signs and symptoms are pain, limited range of motion, and TMJ sounds. TMD is a highly prevalent condition with a multifactorial etiology. Management aims to reduce pain and to improve function using a combination of therapeutic options. Noninvasive techniques are the first option and should be indicated considering the needs of each individual, the clinical features, and the mechanisms involved.