Headaches and myofascial temporomandibular disorders: overlapping entities, separate managements?

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.

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.

The Association Between the Central Sensitisation Inventory and Temporomandibular Disorders Is Confounded by Migraine, Depression, Widespread Pain and Parafunction. A Cross-Sectional Telehealth Study

BACKGROUND

Temporomandibular disorders (TMDs) are conditions that involve the temporomandibular joints, masticatory muscles, and associated tissues, causing orofacial pain. Central sensitisation (CS) is a relevant part of the TMD pathophysiology. Migraine, psychological aspects, parafunctional oral habits and widespread pain are commonly associated with both TMD and CS and could confound the association between them.

OBJECTIVES

To investigate the association between painful TMD and the Central Sensitisation Inventory (CSI) score, and to assess the presence of confounders in this association.

METHODS

Cross-sectional study that assessed women with and without orofacial pain complaints using telehealth. The TMD Pain Screener and an online physical examination determined the presence of painful TMD. The following questionnaires were applied: CSI, Headache Screening Questionnaire, Generalized Anxiety Disorder-7, Patient Health Questionnaire-9, Oral Behavior Checklist, Jaw Functional Limitation Scale and the Nordic musculoskeletal questionnaire. A single regression investigated the association between the CSI score and TMD, and a multiple regression investigated the effect of the other outcomes as possible confounders. Confounding was considered present when the association between TMD and the CSI score changed more than 10% after adding a possible confounder to the regression model.

RESULTS

Forty-two women with painful TMD and 53 without TMD were included. There was a significant association between the CSI score and the presence of painful TMD (R2 = 0.639; p < 0.001). This association changed when the following outcomes were added to the model: presence of migraine, symptoms of depression, widespread pain and parafunctional oral habits.

CONCLUSION

The positive association between TMD and the CSI score was confounded by migraine, symptoms of depression, widespread pain and parafunctional oral habits.

The Link Between Temporomandibular Disorders and Jaw Functional Limitations Among Chinese Adolescents

BACKGROUND

Currently, there is still controversy surrounding the relationship between temporomandibular disorders (TMDs) symptoms and jaw functional limitations. We investigated the distribution of TMDs in senior high school students, including both the number and types of symptoms, and assessed their association with jaw functional limitations. Furthermore, we explored sex differences in these associations.

METHODS

This study was conducted at a public high school in Hefei, Anhui Province, China, with data collected from September to October 2022. All subjects completed questionnaires assessing the anamnestic symptoms of TMDs and the Jaw Functional Limitation Scale (JFLS), and examinations were performed by trained dentists according to the Diagnostic Criteria for TMD. Data were analysed using the Kruskal-Wallis, Mann-Whitney U, and Chi-square tests.

RESULTS

The mean age of the participants (N = 2890) was 17.2 ± 0.14 years and 38.9% were females (61.1% were males). Limitations in self-assessed jaw function were associated with the presence of TMDs (P < .05). Participants with more symptoms reported significantly high levels of functional limitations (P < .05). Compared to male adolescents, female adolescents more commonly experienced TMDs pain and tended to have more symptoms (P < .05). However, no sex differences were observed in most associations between TMDs and jaw functional limitations.

CONCLUSION

TMDs-positive symptoms are common in adolescents. Female adolescents were more affected by TMDs symptoms than male adolescents. Individuals with more TMDs symptoms have greater jaw functional limitations.

Efficacy of acupuncture on craniomandibular myofascial pain in temporomandibular disorder patients: A systematic review

Background

This systematic review aimed to answer the question, "What is the efficacy of acupuncture treatment in patients with temporomandibular disorder (TMD) with myofascial pain?".

Data sources and study selection

This study followed PRISMA guidelines and was registered in PROSPERO. The electronic search strategy was applied to the Scopus, PubMed, Embase, and Science Direct databases. As inclusion criteria, were selected randomized clinical articles that evaluated patients with myofascial pain symptoms treated by acupuncture without the restriction of time and language.

Results

The search in the databases resulted in 286 articles, after removing the duplicates 251 were analyzed by title and abstract. Twenty were selected for full reading and 10 were included in the systematic review. The studies evaluated acupuncture treatments by puncture and laser, auriculotherapy by puncture and laser, and an occlusal device for treating myofascial TMD.

Conclusions

Comparing acupuncture with placebo acupuncture, it was observed that it is effective for subjective pain relief and palpation of orofacial structures with immediate results; it should be noted that there is still no specific protocol and that the duration of treatment must be personalized. When comparing it with the occlusal device, the associated treatment has enhanced the results. Future studies are suggested by the current literature gap that prevents the determination of clinical guidelines for effective acupuncture treatment in TMD patients with myofascial pain.

Practical implications

Laser and needle puncture acupuncture treatment and laser and needle puncture auriculotherapy have shown favorable results in short-term myofascial pain relief. The need for long-term studies to assess benefits and reduce possible biases is highlighted.

Clinical trial registry name

PROSPERO (CRD42021271505).

The effect of different pain characteristics on jaw functional limitations in patients with temporomandibular disorders

BACKGROUND

Patients with painful temporomandibular disorders (TMD) more often experience jaw functional limitations. The study of jaw functional limitations should be primarily focused on painful TMD.

OBJECTIVES

The impact of TMD pain characteristics (source, chronicity and intensity) on jaw functional limitations were evaluated using Jaw Functional Limitation Scale (JFLS).

METHODS

This cross-sectional study reviewed the dental records and self-report questionnaires of patients with painful TMD. The pain source, chronicity and intensity were evaluated to study the TMD pain characteristics. The jaw functional limitations were analysed using the Thai version of the JFLS.

RESULTS

A total of 176 patients with painful TMD were included in this study. The jaw functional limitations were affected only by pain intensity. Patients with TMD with severe pain intensity had significantly higher jaw functional limitations than those with mild-to-moderate pain intensity (p < .05). A significant association was observed between pain intensity and jaw functional limitations (p < .05). Mastication was highly restricted by pain intensity (odd ratio = 1.39, 95% confidence interval = 1.16-1.67).

CONCLUSION

The present study found a significant effect of TMD pain intensity on jaw functional limitations. Patients with severe TMD pain intensity were more likely to experience jaw functional limitations, particularly mastication limitation. Management focusing on reduction of pain intensity may improve jaw functions in patients with TMD.

Comparison of force profiles from two musculoskeletal palpation methods: A methodological study

BACKGROUND

The Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) protocol recommends a 5 s and 1 kg force dynamic palpation around the lateral condylar pole of the temporomandibular joint. However, the accuracy and precision of the generated force are not known.

OBJECTIVE

To assess and compare the force profiles generated from dynamic palpation manually and using a palpometer, based on the forces and time recommendations suggested by the DC/TMD protocol.

METHODS

Nineteen healthy adults applied forces of 0.5 kg, 1.0 kg and 2.0 kg on a calibrated force sensor in a circular motion within target times of 2 s and 5 s. Participants used their right index finger for manual palpation and a calibrated palpometer for device-assisted palpation. Ten repetitions of each target force at both target times were applied. Time taken to complete each application was recorded. Repeated measures analysis of variance was used for analysis of accuracy measured as the relative difference between targeted force and actual force values and precision measured as the coefficient of variation (CV) within the 10 repeated measurements.

RESULTS

Accuracy was significantly lower (better) and precision higher (lower CV) with the palpometer than with manual palpation (p < .001). There were significant differences in accuracy and precision between the different forces but not palpation times. Most participants could not achieve the target times and tended to be faster, irrespective of the palpation method (p > .063).

CONCLUSION

A palpometer is a more accurate and precise palpation method for dynamic force assessment compared to manual palpation; however, it remains difficult to standardize the palpation duration.

Effects on temporomandibular disorder in the treatment of tension-type headache with acupuncture and therapeutic exercises. A secondary analysis from a randomized controlled trial

OBJECTIVES

To examine the effects of acupuncture and therapeutic exercise alone and in combination on temporomandibular joint symptoms in tension-type headache and to evaluate the potential interaction of existing temporomandibular dysfunction on the success of headache treatment.

DESIGN

Pre-planned secondary analysis of a randomized controlled, non-blinded trial.

SETTING

Outpatient clinic of a German university hospital.

SUBJECTS

Ninety-six Participants with frequent episodic or chronic tension-type headache were randomized to one of four treatment groups.

INTERVENTIONS

Six weeks of acupuncture or therapeutic exercise either as monotherapies or in combination, or usual care. Follow-up at 3 and 6 months.

MAIN MEASURES

Subjective temporomandibular dysfunction symptoms were measured using the Functional Questionnaire Masticatory Organ, and the influence of this sum score and objective initial dental examination on the efficacy of headache treatment interventions was analyzed.

RESULTS

Temporomandibular dysfunction score improved in all intervention groups at 3-month follow-up (usual care: 0.05 [SD 1.435]; acupuncture: -5 [SD 1.436]; therapeutic exercise: -4 [SD 1.798]; combination: -3 [SD 1.504]; P = 0.03). After 6 months, only acupuncture (-6 [SD 1.736]) showed a significant improvement compared to the usual care group (P < 0.01). Subjective temporomandibular dysfunction symptoms had no overall influence on headache treatment.

CONCLUSIONS

Only acupuncture had long-lasting positive effects on the symptoms of temporomandibular dysfunction. Significant dental findings seem to inhibit the efficacy of acupuncture for tension-type headache.

Correlates between temporomandibular disorder severity, emotional distress, and eudaimonic well-being among young adults

OBJECTIVES

This study examined the correlates between severity of temporomandibular disorders (TMDs), emotional distress, and eudaimonic well-being.

SUBJECTS AND METHODS

TMD severity, negative emotions, and eudaimonia were assessed with the Fonseca Anamnestic Index (FAI), Depression, Anxiety, Stress Scales-21 (DASS-21), and Psychological Well-being Scale-18 (PWBS-18) in a cohort of community young adults. Statistical evaluations were done with non-parametric tests/correlation and multivariate regression analyses (α = 0.05).

RESULTS

Amongst the 873 participants (mean age 19.8 ± 1.66 years), 40.7%, 49.0%, and 10.3% had no (NT), mild (MT), and moderate-to-severe (ST) TMD, respectively. Significant differences in total-DASS, depression, anxiety, and stress were ST ≥ MT > NT. Significant variances in total-PWSB and self-acceptance were NT > MT > ST while that for environmental mastery, positive relations, and purpose in life were NT > MT, ST. An inverse relationship was discerned between total-DASS and total-PWBS (correlation coefficient = -0.54). The prospect of ST was increased by anxiety but reduced by positive relations and self-acceptance.

CONCLUSIONS

Young adults with mild and moderate-to-severe TMD experienced substantially higher emotional distress and lower eudaimonia than those with no TMD. As emotional distress and eudaimonic well-being are interrelated, positive psychological interventions may be beneficial for managing TMD-related psychosocial disabilities.

Effectiveness of Dry Needling versus Manual Therapy in Myofascial Temporomandibular Disorders: A Single-Blind Randomized Controlled Trial

Dry needling (DN) is an invasive physiotherapy technique employed for reducing myofascial pain. To compare the effectiveness of dry needling (DN) versus manual therapy (MT) in improving pain, active maximal mouth opening (AMMO) and cervical disability in patients with myofascial pain from temporomandibular disorders (TMDs) were investigated against these treatments. A single-blind, randomized controlled trial was carried out. Individuals (n = 50) with TMDs were randomly allocated in a 1:1 ratio to the DN (n = 25) or MT group (n = 25). Each group received three sessions, separated by 4 days, of either DN or MT. Outcomes were assessed according to pain intensity (Numeric Pain Rating Scale), AMMO (cm), disability (Neck Disability Index), and pressure-pain threshold (PPT) (digital algometry) from the active myofascial trigger points. In both groups, pain and neck disability were significantly lower at the end of treatment compared with those measured at baseline (pain: -2.52 with 95% CI: -3.43 to -1.60 for DN group; pain: -2.92 with 95% CI: -3.77 to -2.07 for MT group; disability: -3.2 with 95% CI: -4.31 to -2.09 for DN group; disability: -2.68 with 95% CI: -3.56 to -1.79 for MT group), but not were not lower after the first session, without differences between the groups. AMMO was significantly higher after the first session (0.16 with 95% CI: 0.03 to 0.29 for DN group; 0.30 with 95% CI: 0.20 to 0.41 for MT group) and at the end of treatment in both groups (0.27 with 95% CI: 0.14 to 0.41 for DN group; 0.37 with 95% CI: 0.22 to 0.52 for MT group) compared with the baseline measurements. Finally, PPT results for the masseter and pterygoid muscles were significantly higher at the end of treatment in both groups (without statistically significant differences between groups), but not after the first session. The assessed therapies, DN and MT, are equally effective in improving pain, AMMO, cervical disability, and PPT in the muscles directly involved in the temporomandibular joint biomechanics of patients with myofascial TMDs.

Craniofacial disorders and headaches. A narrative review

OBJECTIVES

Craniofacial- and headache disorders are common co-morbid disorders. The aim of this review is to provide an overview of the research discussing craniofacial pain, especially temporomandibular disorders, and its relationship and impact on headaches, as well as suggestions for diagnostic assessment tools and physical therapeutic management strategies.

METHOD

A narrative structured review was performed. A search was conducted in MEDLINE using terms related to craniofacial pain and headaches. Additionally, papers regarding this topic were also extracted from the authors' personal libraries. Any study design (i.e., RCT, observational studies, systematic review, narrative review) that reported the concepts of interest was included, using Covidence. Results were narratively synthesized and described.

RESULTS

From an epidemiological perspective, craniofacial pain and headaches are strongly related and often co-existing. This may be due to the neuroanatomical connection with the trigeminal cervical complex, or due to shared predisposing factors such as age, gender, and psychosocial factors. Pain drawings, questionnaires, and physical tests can be used to determine the cause of pain, as well as other perpetuating factors in patients with headaches and craniofacial pain. The evidence supports different forms of exercise and a combination of hands-on and hands-off strategies aimed at both the craniofacial pain as well as the headache.

CONCLUSION

Headaches may be caused or aggravated by different disorders in the craniofacial region. Proper use of terminology and classification may help in understanding these complaints. Future research should look into the specific craniofacial areas and how headaches may arise from problems from those regions. (249 words).

A rose by another name? Characteristics that distinguish headache secondary to temporomandibular disorder from headache that is comorbid with temporomandibular disorder

ABSTRACT

Co-occurring pain conditions that affect overlapping body regions are complicated by the distinction between primary vs secondary pain conditions. We investigate the occurrence of headache and painful temporomandibular disorder (TMD) in a community-based, cross-sectional study of US adults in the Orofacial Pain: Prospective Evaluation and Risk Assessment (OPPERA-II) study. A specific goal was to determine whether headache attributed to TMD is separable from primary headache. Using DC/TMD and International Classification of Headache Disorders-third edition criteria, 3 groups of individuals were created: (a) headache without TMD; (b) headache comorbid with TMD; and (c) headache attributed to TMD. Regression models compared study groups according to demographic and comorbid characteristics, and post hoc contrasts tested for differences. Descriptive statistics and Cohen d effect size were computed, by group, for each predictor variable. Differences in continuous predictors were analyzed using one-way analysis of variance. Nearly all demographic and comorbid variables distinguished the combined headache and TMD groups from the group with headache alone. Relative to the reference group with primary headache alone, markers related to headache, TMD, somatic pain processing, psychosocial, and health conditions were substantially greater in both headache comorbid with TMD and headache attributed to TMD, attesting to their qualitative similarities. However, effect sizes relative to the reference group were large for headache comorbid with TMD and larger again for headache attributed to TMD, attesting to their separability in quantitative terms. In summary, the presence of overlapping painful TMD and headache adds substantially to the biopsychosocial burden of headache and points to the importance of comprehensive assessment and differential management.

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.

Temporomandibular disorders and neck pain in primary headache patients: a retrospective machine learning study

OBJECTIVES

To evaluate the linkage underpinning different clinical conditions as painful TMD and neck pain in patients affected by primary headaches.

MATERIALS AND METHODS

In this machine learning study, data from medical records of patients with headaches as migraine, tension-type headache (TTH) and other primary ones, referring to a University Hospital over a 10-year period were analysed. VAS was used to evaluate the intensity of the TMD and neck pain. Moreover, the magnetic resonance imaging was used to supplement the clinical data.

RESULTS

A total of 300 patients (72 male, 228 female), mean aged 37.78 ± 5.11 years, were included. Higher TMD and neck pain VAS in migraine patients were reported. The machine learning analysis focussed on type of primary headache demonstrated that a higher TMD VAS was correlated to migraine, whereas a higher neck pain VAS was correlated to TTH or migraine. Concerning the TMD type, arthrogenous and mixed TMD were correlated to mild-moderate TMD pain (depending on neck pain intensity), whereas myogenic TMD was correlated to moderate-severe TMD pain.

CONCLUSIONS

Machine-learning approach highlighted the complexity of diagnosis process and demonstrated that neck pain might be an influential variable on the belonging to different group of headaches in TMD patients.

Sleep Bruxism in Puerperal Women: Data from a Population-Based Survey

OBJECTIVE

To evaluate the self-reported SB prevalence and explore associated risk factors in puerperal women who had given birth in Rio Grande, Southern Brazil.

METHODS

A single, standardized questionnaire was given within the 48 h postpartum period. Self-reported SB was the main outcome investigated. Chi-square test was used to compare proportions, and Poisson regression with robust variance adjustment was used in the multivariate analysis.

RESULTS

A total of 2225 women were included. Only 79 (3.6%) of these reported clenching or grinding their teeth during sleep. Adjusted analysis showed that the higher education level of the mothers (PR = 3.07; 95% CI 1.49-6.28; P = 0.006); living with three or more persons in the household (PR = 0.54; 95% CI 0.34-0.84; P = 0.007); medication intake during pregnancy (PR = 1.68; 95% CI 1.09-2.58; P = 0.017); smoking (PR = 1.93; 1.16-3.23; P = 0.024), or ever smoked (PR = 1.82; 95% CI 0.85-3.90; P = 0.024); severe anxiety (PR = 1.36; 95% CI 0.61-3.02; P = 0.005); and headache upon waking (PR = 4.19; 95% CI 1.95-9.00; P < 0.001) were significantly associated with self-reported SB.

CONCLUSION FOR PRACTICE

Our data pointed towards new factors in a specific group of women that may be relevant for preventing sleep-related behaviors in the pregnancy-puerperal cycle. The higher levels of education, medication intake, smoking or even smoked, severe anxiety, the higher the probability of puerperal woman to self-report SB. The nighttime tooth clenching strongly increased headache upon waking.

Sleep-related factors and orofacial pain symptoms associated with rhythmic masticatory muscle activity frequency scored by polysomnography recordings: A case-control study

OBJECTIVE

This study aimed to evaluate the influence of the frequency of rhythmic masticatory muscle activity per hour (RMMA/h) scored by polysomnography (PSG) recordings on sleep-related factors and orofacial pain symptoms.

METHODS

According to RMMA/h frequency, participants were assigned either to the control group (i.e., CRMMA, n = 40); or the case group according to high (i.e., HRMMA, n = 12) or low (LRMMA, n = 28) RMMA/h frequency. Fisher's exact (nominal variables), One-way Analysis of Variance followed by post-hoc Tukey (continuous variables) and Poisson Regression tests were used to calculate orofacial pain symptoms and sleep-related breathing, behavior, and architecture differences between controls versus cases at a significance level of 5%.

RESULTS

The CRMMA differed from HRMMA and LRMMA subgroups considering orofacial pain, self-reported tooth clenching or grinding, obstructive sleep apnea (OSA), snoring, and most variables considering sleep architecture (P ≤ 0.05). Multivariate adjusted Poisson regression analysis revealed that bruxers, regardless of RMMA/h frequency, presented a significantly higher prevalence rate (PR) related to orofacial pain (PR 1.68; P = 0.025) and self-reported behavior (PR 1.71; P = 0.012).

CONCLUSION

Significant differences in N1, N2 and N3 stages, arousals, arousal per hour, and sleep onset latency variables were found comparing bruxer with high or low RMMA/h frequency. Compared to controls, bruxers presented higher PR related to headache and self-reported tooth clenching or grinding.

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 Role of Neuro-Immune Interaction in Chronic Pain Conditions; Functional Somatic Syndrome, Neurogenic Inflammation, and Peripheral Neuropathy

Functional somatic syndromes are increasingly diagnosed in chronically ill patients presenting with an array of symptoms not attributed to physical ailments. Conditions such as chronic fatigue syndrome, fibromyalgia syndrome, or irritable bowel syndrome are common disorders that belong in this broad category. Such syndromes are characterised by the presence of one or multiple chronic symptoms including widespread musculoskeletal pain, fatigue, sleep disorders, and abdominal pain, amongst other issues. Symptoms are believed to relate to a complex interaction of biological and psychosocial factors, where a definite aetiology has not been established. Theories suggest causative pathways between the immune and nervous systems of affected individuals with several risk factors identified in patients presenting with one or more functional syndromes. Risk factors including stress and childhood trauma are now recognised as important contributors to chronic pain conditions. Emotional, physical, and sexual abuse during childhood is considered a severe stressor having a high prevalence in functional somatic syndrome suffers. Such trauma permanently alters the biological stress response of the suffers leading to neuroexcitatory and other nerve issues associated with chronic pain in adults. Traumatic and chronic stress results in epigenetic changes in stress response genes, which ultimately leads to dysregulation of the hypothalamic-pituitary axis, the autonomic nervous system, and the immune system manifesting in a broad array of symptoms. Importantly, these systems are known to be dysregulated in patients suffering from functional somatic syndrome. Functional somatic syndromes are also highly prevalent co-morbidities of psychiatric conditions, mood disorders, and anxiety. Consequently, this review aims to provide insight into the role of the nervous system and immune system in chronic pain disorders associated with the musculoskeletal system, and central and peripheral nervous systems.

The Role of Pain Inflexibility and Acceptance among Headache and Temporomandibular Disorders Patients

Temporomandibular disorders (TMD) and headache are complex. This study aims to assess the association between TMD, headache, and psychological dimensions such as psychological inflexibility and pain acceptance. The sample consisted of 120 participants following a non-probabilistic convenience sampling strategy through a direct invitation to the patients attending our facilities and their relatives (n = 61 diagnosed with headache, n = 34 diagnosed with TMD-headache, n = 25 control group). Diagnostic Criteria for Temporomandibular Disorders (DC-TMD), International Classification of Headache Disorders (ICHD-3 beta version), Chronic Pain Acceptance Questionnaire (CPAQ-8), and Psychological Inflexibility in Pain Scale (PIPS) were used as assessment tools. One-way ANOVA, multiple regression analysis (MRA), and the Johnson-Neyman approach were run by IBM SPSS, version 27 (IBM^® Company, Chicago, IL, USA). The significance level was 0.05. One third of our sample presented with headache with TMD. Females were predominant. Males with headache, no systemic disease, less pain severity but higher frequency, living longer with the disease and having sensitive changes, showed higher pain acceptance. When headache occurs with TMD, women with higher education, no headache family history, less pain, and no motor changes showed higher pain acceptance. Patients with both conditions are more liable to have chronic pain and pain inflexibility. Pain intensity and willingness explain 50% of the psychological inflexibility in the headache group. In our sample, individuals suffering from both conditions show greater pain inflexibility, implicating more vivid suffering experiences, leading to altered daily decisions and actions. However, further studies are needed to highlight this possible association.

Viability of the quintessential 5 temporomandibular disorder symptoms as a TMD screener

OBJECTIVE

This study explored the viability of using the 5 temporomandibular disorder (TMD) symptoms (5Ts) of the Diagnostic Criteria for TMDs (DC/TMD) as a TMD screener.

STUDY DESIGN

A total of 1039 adults (≥18 years old) with a mean age of 32.65 ± 12.95 years (77.4% women) from a tertiary dental hospital were enrolled. The 5Ts questionnaire (involving items on TMD/facial pain, headaches, temporomandibular joint noises, and closed- and open-locking) was administered, and TMD diagnoses were derived through clinical interviews and examinations, radiographic investigations, and the DC/TMD diagnostic algorithms and diagnostic tree. Diagnostic accuracy of the 5Ts was assessed using the area under the receiver operating characteristics curve and various measures, including sensitivity, specificity, predictive values, and likelihood ratios.

RESULTS

Among the participants, 80.2% (n = 833) were 5Ts-positive, and 19.8% (n = 206) were 5Ts-negative, whereas 51.3% and 85.7% received at least 1 pain-related and intra-articular DC/TMD diagnosis, respectively. The 5Ts showed high accuracy for detecting all TMDs, pain-related and intra-articular, with area under the receiver operating characteristics curves of 0.98, 1.00, and 0.98, respectively. Sensitivity ranged from 96.1% to 99.2%, whereas specificity was 100.0%.

CONCLUSIONS

The 5Ts demonstrated high diagnostic accuracy for identifying pain-related and/or intra-articular disorders.

Remote physical examination for temporomandibular disorders

ABSTRACT

There is a need to further develop telemedicine approaches because of the immediate and perhaps long-term consequences of the coronavirus disease 2019. Thus, a remote protocol for assessment of patients with temporomandibular disorders (TMD) was developed, and the agreement of this protocol was compared with the guidelines of the Diagnostic Criteria for TMD (DC/TMD). A total of 16 individuals were first assessed by a reference standard examination (RSE) and 3 other examinations applied in a random order by 3 examiners: standard physical examination (standard examination), physical examination keeping 2-m distance (physical distanced examination), and examination conducted with the aid of video communication technology (video communication examination). The primary outcomes were the diagnoses of myalgia of the masseter and temporalis muscles and arthralgia. The diagnoses of intra-articular joint disorders were considered secondary outcomes because of a less impact on psychosocial functioning and quality of life when compared with the pain-related diagnoses. The Fleiss kappa coefficient and its 95% confidence interval were computed to determine the level of agreement in diagnoses between each examination protocol and the RSE. There was substantial to almost perfect agreement between the RSE and all the examination protocols for the diagnoses of myalgia (0.86-1.00) and arthralgia (0.74-0.87) (P < 0.001). On the other hand, there was an overall poor agreement (0.30-0.58) between the RSE and all the protocols for the diagnosis of disk displacement with reduction. Remote assessment of patients with pain-related TMD is feasible and presents a high degree of accuracy.

Comparison of factors affecting patients with a myofascial temporomandibular disorder with and without sleep bruxism

Aims and Background

The aim of the present study was to evaluate the relationship between jaw function, neck disability, sleep quality, fatigue, and headache in patients with myofascial temporomandibular disorder (TMD) with sleep Bruxism (SB) and without it (non-SB).

Subjects and Methods

This case-control study was conducted with a total of 200 myofascial TMD patients, comprising 91 identified as SB and 109 as non-SB. The Jaw Function Limitations Scale (JFLS), Neck Disability Index (NDI), Pittsburgh Sleep Quality Index (PSQI), Fatigue Severity Scale (FSS), and Headache Impact Test-6 (HIT-6) scales and indexes were used.

Results

In the group with SB compared to the non-SB group, JFLS, NDI, PUKI, and FSS scores were statistically significantly higher (P < 0.001). No statistically significant difference was found between the groups in terms of visual analog scale (VAS) (P = 0.127) and HIT-6 scores (P = 0.365). The probability of having JFLS in patients with SB compared to those without was folded 3.551 times (P = 0.002), and the probability of having NDI increased 3.473 times (P = 0.002). In addition, SB was observed to trigger poor sleep quality (P < 0.001). There was no statistically significant determinant of bruxism on FSS (P = 0.196), and on HIT-6 (P = 0.488).

Conclusion

It can be concluded that SB causes limitation of the jaw's functional activities, neck problems, and decreased sleep quality in myofascial TMD. These findings emphasize the importance of considering SB when evaluating and treating patients with myofascial TMD problems.

Scoping review and interpretation of myofascial pain/fibromyalgia syndrome: An attempt to assemble a medical puzzle

BACKGROUND

Myofascial Pain Syndrome (MPS) is a common, overlooked, and underdiagnosed condition and has significant burden. MPS is often dismissed by clinicians while patients remain in pain for years. MPS can evolve into fibromyalgia, however, effective treatments for both are lacking due to absence of a clear mechanism. Many studies focus on central sensitization. Therefore, the purpose of this scoping review is to systematically search cross-disciplinary empirical studies of MPS, focusing on mechanical aspects, and suggest an organic mechanism explaining how it might evolve into fibromyalgia. Hopefully, it will advance our understanding of this disease.

METHODS

Systematically searched multiple phrases in MEDLINE, EMBASE, COCHRANE, PEDro, and medRxiv, majority with no time limit. Inclusion/exclusion based on title and abstract, then full text inspection. Additional literature added on relevant side topics. Review follows PRISMA-ScR guidelines. PROSPERO yet to adapt registration for scoping reviews.

FINDINGS

799 records included. Fascia can adapt to various states by reversibly changing biomechanical and physical properties. Trigger points, tension, and pain are a hallmark of MPS. Myofibroblasts play a role in sustained myofascial tension. Tension can propagate in fascia, possibly supporting a tensegrity framework. Movement and mechanical interventions treat and prevent MPS, while living sedentarily predisposes to MPS and recurrence.

CONCLUSIONS

MPS can be seen as a pathological state of imbalance in a natural process; manifesting from the inherent properties of the fascia, triggered by a disrupted biomechanical interplay. MPS might evolve into fibromyalgia through deranged myofibroblasts in connective tissue ("fascial armoring"). Movement is an underemployed requisite in modern lifestyle. Lifestyle is linked to pain and suffering. The mechanism of needling is suggested to be more mechanical than currently thought. A "global percutaneous needle fasciotomy" that respects tensegrity principles may treat MPS/fibromyalgia more effectively. "Functional-somatic syndromes" can be seen as one entity (myofibroblast-generated-tensegrity-tension), sharing a common rheuma-psycho-neurological mechanism.

Evaluation of the Effectiveness of Dry Needling in the Treatment of Myogenous Temporomandibular Joint Disorders

Background and Objectives: The objective of our clinical trial was to determine the effectiveness of the deep dry needling technique (DDN) (neuromuscular deprogramming) as a first step in the treatment of temporomandibular disorders. Methods and Materials: The double-blind randomized clinical trial comprised 36 patients meeting the inclusion criteria who had signed the corresponding informed consent form. The participants were randomly distributed into two groups, the Experimental group (Group E) and the Control group (Group C). Group E received bilateral DDN on the masseter muscle, while Group C received a simulation of the technique (PN). All the participants were evaluated three times: pre-needling, 10 min post-needling, and through a follow-up evaluation after 15 days. These evaluations included, among other tests: pain evaluation using the Visual Analog Scale (VAS) and bilateral muscle palpation with a pressure algometer; evaluation of the opening pattern and range of the mouth, articular sounds and dental occlusion using T-scans; and electromyography, which was used to evaluate the muscle tone of the masseter muscles, in order to control changes in mandibular position. Results: Digital control of occlusion using Tec-Scan (digital occlusion analysis) showed a significant reduction both in the time of posterior disclusion and in the time needed to reach maximum force in an MI position after needling the muscle, which demonstrated that there were variations in the static position and the trajectory of the jaw. The symmetry of the arch while opening and closing the mouth was recovered in a centric relation, with an increase in the opening range of the mouth after the procedure. Conclusions: facial pain is significantly reduced and is accompanied by a notable reduction in muscle activity after needling its trigger points.

International Classification of Orofacial Pain – ICOP – Brazilian Portuguese version

There is no abstract since it is an Editorial. 

Association between primary headaches and temporomandibular disorders: A systematic review and meta-analysis

BACKGROUND

The primary objective of this systematic review was to answer the following question systematically: Is there any association between primary headaches (PHs) and temporomandibular disorders (TMDs) in adults?

TYPES OF STUDIES REVIEWED

The protocol was registered with the International Prospective Register of Systematic Reviews. The authors performed the search in 7 main databases and 3 gray literature sources. The included articles had to have adult samples. PHs must have been diagnosed using the International Classification of Headache Disorders, and TMDs must have been diagnosed using Research Diagnostic Criteria for Temporomandibular Disorders, Diagnostic Criteria for Temporomandibular Disorders, or International Classification of Orofacial Pain. Risk of bias was evaluated using the Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review Instrument tools. The meta-analysis was performed using Review Manager software, Version 5.4. Certainty of evidence was screened according to Grading of Recommendations Assessment, Development and Evaluation.

RESULTS

Eight of 2,574 articles reviewed met the inclusion criteria for qualitative analysis and, of these, 6 met the inclusion criteria for quantitative analysis. Odds ratios (ORs) for painful TMD and tension-type headache (OR, 3.16; 95% CI, 1.80 to 5.54 to OR, 13.06; 95% CI, 2.79 to 61.12), migraines (OR, 5.35; 95% CI, 3.04 to 9.40 to OR, 6.22; 95% CI, 3.81 to 10.14), and chronic headaches (OR, 40.40; 95% CI, 8.67 to 188.15 to OR, 95.93; 95% CI, 12.53 to 734.27) were calculated. Articular TMDs without pain were evaluated in only 1 article, in which ORs of 1.78 (95% CI, 0.90 to 3.51) for migraines and 1.04 (95% CI, 0.53 to 2.06) for tension-type headache were reported. Three studies were classified as moderate risk of bias and 5 as low risk of bias. The certainty of evidence varied between very low and low.

CONCLUSIONS AND PRACTICAL IMPLICATIONS

Recognizing the positive association between painful TMD and PHs can help dentists and physicians treat the pain and avoid it, or recommend the patient to a specialist.

Effects of therapeutic and aerobic exercise programs in temporomandibular disorder-associated headaches

Objective

To assess the effects of three 8-week exercise programs on the frequency, intensity, and impact of headaches in patients with headache attributed to temporomandibular disorder (TMD).

Methodology

Thirty-six patients diagnosed with headache attributed to TMD participated in the study and were divided into three groups of 12 patients: a therapeutic exercise program (G1, mean age: 26.3±5.6 years), a therapeutic and aerobic exercise program (G2, mean age: 26.0±4.6 years), and an aerobic exercise program (G3, 25.8±2.94 years). Headache frequency and intensity were evaluated using a headache diary, and the adverse headache impact was evaluated using the Headache Impact Test (HIT-6). The intensity was reported using the numerical pain rating scale. These parameters were evaluated twice at baseline (A01/A02), at the end of the 8-week intervention period (A1), and 8–12 weeks after the end of the intervention (A2).

Results

At A1, none of the G2 patients reported having headaches, in G1, only two patients reported headaches, and in G3, ten patients reported headache. The headache intensity scores (0.3 [95% CI: -0.401, 1.068]), (0.0 [95% CI: -0.734, 0.734]) and HIT-6 (50.7 [95% CI: 38.008, 63.459]), (49.5 [95% CI: 36.808, 62.259]), significantly decreased in G1 and G2 at A1. At A2 headache intensity scores (0.5 [95% CI: -0.256, 1.256]), (0.0 [95% CI: -0.756, 0.756]) and HIT-6 (55.1 [95% CI: 42.998, 67.268]), (51.7 [95% CI: 39.532, 63.802]) in G1 and G2 haven’t change significantly. The effects obtained immediately after the completion of the intervention programs were maintained until the final follow-up in all groups.

Conclusion

The programs conducted by G1 (therapeutic exercises) and G2 (therapeutic and aerobic exercise) had significant results at A1 and A2.

Standardized palpation of the temporalis muscle evoke referred pain and sensations in individuals without TMD

OBJECTIVES

This study aimed to determine if standardized palpations of the temporalis muscle evoke referred pain and/or sensations in individuals without TMD.

MATERIALS AND METHODS

This was a randomized, single-blinded study. The mechanical sensitivity of the right temporalis muscle was assessed in 32 participants without TMD with nine different stimulations to 15 test sites using palpometers (different stimulus intensities (0.5, 1.0, and 2.0 kg) and durations (2, 5, and 10 s). After each stimulus, participants were asked to score perceived pain intensity and intensity of unpleasantness on a 0-100 numeric rating scale as an indicator of mechanical sensitivity in the temporalis muscle and to indicate any areas of referred pain/sensations on a body chart.

RESULTS

Pain intensity significantly differed between palpation durations, intensities, and test sites (P < 0.001). In contrast, unpleasantness significantly differed between palparation duration and intensities (P < 0.001), but not test sites. Participants more frequently reported referred pain/sensations evoked by the 10-s (34.4%) as opposed to the 2-s (6.3%) and 5-s (15.6%) palpation duration at the 2.0-kg stimulus intensity (P < 0.05).

CONCLUSIONS

Our present results indicate that referred pain/sensations in the orofacial region can be evoked by standardized palpation of the temporalis muscle and influenced by the palpation duration in individuals without TMD.

CLINICAL RELEVANCE

Referred pain/sensations from the temporalis muscle were duration- and intensity-dependent processes originating from local stimuli.

Pain in the temple? Headache, muscle pain or both: A retrospective analysis

AIM

Headache attributed to temporomandibular disorders and myalgia are two diagnoses included in the diagnostic criteria for temporomandibular disorders (DC/TMD). However, it is not clear if these two diagnoses are different clinical entities given their similar presentation and way in which they are diagnosed, when the myalgia is within the temporalis muscle. The purpose of this retrospective study was to assess the overlap between headache attributed to temporomandibular disorders and myalgia of the temporalis muscle.

METHODS

The charts of 671 patients seeking treatment at the Section of Orofacial Pain and Jaw Function, Aarhus University, Denmark, between January 2015 and February 2020 were screened for a diagnosis of headache attributed to temporomandibular disorders, myalgia of the temporalis muscle, or both.

RESULTS

A total of 89 patients fulfilled the DC/TMD criteria for either headache attributed to TMD, myalgia of the temporalis or both. Of these, two had a diagnosis of headache attributed to TMD, 16 of myalgia of the temporalis, and 71 were diagnosed with both. In 97.3% of the times that headache attributed to temporomandibular disorders was diagnosed, the patient was also diagnosed with myalgia of the temporalis. The Jaccard index was 0.8, indicating a substantial overlap between the two diagnoses. Finally, the overlap of pain location between the two diagnoses was substantial, with a Jaccard index of 0.9.

CONCLUSIONS

In the present study, headache attributed to temporomandibular disorders was almost exclusively diagnosed together with myalgia of the temporalis. Therefore, we propose that headache attributed to temporomandibular disorders and myalgia of the temporalis muscle have more clinical similarities than differences and as such could be considered one single clinical entity. Further studies will be needed to address the clinical consequences of this proposal.

Effect of comorbid migraine on propranolol efficacy for painful TMD in a randomized controlled trial

Introduction

The migraine-preventive drug propranolol is efficacious in reducing pain from temporomandibular disorder, suggesting potential modifying or mediating effects of comorbid migraine.

Methods

In this randomized controlled trial, myofascial temporomandibular disorder patients were treated with propranolol or placebo for 9 weeks. The primary endpoint was change in a facial pain index derived from daily symptom diaries. Linear and logistic regression models tested for a migraine × treatment-group interaction in reducing facial pain index. Counterfactual models explored changes in headache impact and heart rate as mediators of propranolol's efficacy.

Results

Propranolol's efficacy in reducing facial pain index was greater among the 104 migraineurs than the 95 non-migraineurs: For example, for the binary ≥ 30% reduction in facial pain index, odds ratios were 3.3 (95% confidence limits: 1.4, 8.1) versus 1.3 (0.5, 3.2), respectively, although the interaction was statistically non-significant (p = 0.139). Cumulative response curves confirmed greater efficacy for migraineurs than non-migraineurs (differences in area under the curve 26% and 6%, respectively; p = 0.081). While 9% of the treatment effect was mediated by reduced headache impact, 46% was mediated by reduced heart rate.

Conclusions

Propranolol was more efficacious in reducing temporomandibular disorder pain among migraineurs than non-migraineurs, with more of the effect mediated by reduced heart rate than by reduced headache impact.

Study identification and registration

SOPPRANO; NCT02437383; https://clinicaltrials.gov/ct2/show/NCT02437383

Increased substance P-like immunoreactivities in parabrachial and amygdaloid nuclei in a rat model with masticatory myofascial pain

This study explores the involvement of substance P (SP) in the parabrachial nucleus (PBN) and central amygdaloid nucleus (CeA) in the nociception-emotion link and of rats with masticatory myofascial pain (MMP) induced by chronic tetanic eccentric muscle contraction. A total of 18 rats were randomly and equally assigned for MMP (MMP group) and sham-MMP induction (sMMP group). MMP was induced by electrical-stimulated repetitive tetanic eccentric contraction of the masseter muscle for 14 consecutive days. Myofascial trigger points in the masseter muscle were identified by palpable taut bands, increased prevalence of endplate noise (EPN), focal hypoechoic nodules on ultrasound and restricted jaw opening. All animals were killed for morphological and SP immunohistochemical analyses. Chronic tetanic eccentric contraction induced significantly thicker masseter muscle confirmed by hypoechogenicity, increased prevalence and amplitudes of EPN, and limited jaw opening. Immunohistochemically, the SP-like positive neurons increased significantly in PBN and CeA of the MMP group. Our results suggested that MMP increases the SP protein levels in PBN and CeA, which play important roles in MMP-mediated chronic pain processing as well as MMP-related emotional processes.

The Role of Descending Pain Modulation in Chronic Primary Pain: Potential Application of Drugs Targeting Serotonergic System

Chronic primary pain (CPP) is a group of diseases with long-term pain and functional disorders but without structural or specific tissue pathologies. CPP is becoming a serious health problem in clinical practice due to the unknown cause of intractable pain and high cost of health care yet has not been satisfactorily addressed. During the past decades, a significant role for the descending pain modulation and alterations due to specific diseases of CPP has been emphasized. It has been widely established that central sensitization and alterations in neuroplasticity induced by the enhancement of descending pain facilitation and/or the impairment of descending pain inhibition can explain many chronic pain states including CPP. The descending serotonergic neurons in the raphe nuclei target receptors along the descending pain circuits and exert either pro- or antinociceptive effects in different pain conditions. In this review, we summarize the possible underlying descending pain regulation mechanisms in CPP and the role of serotonin, thus providing evidence for potential application of analgesic medications based on the serotonergic system in CPP patients.

Alterations in Surface Electromyography Are Associated with Subjective Masticatory Muscle Pain

Background

Tenderness of masseters and temporalis can be considered a relevant tool for diagnosis of myo-type craniofacial pain disorders, but a limit of pain score systems is that they are based on subjective pain perception. Surface electromyography (sEMG) is a noninvasive and reliable tool for recording muscle activity. Therefore, we investigated whether a correlation exists between tenderness on masseters and temporalis, assessed by subjective pain scale, and muscles activity, evaluated by sEMG, in patients with painful temporomandibular disorder (TMD) and concurrent tension-type headache (TTH).

Methods

A cross-sectional study on fifty adult volunteer patients with TMD and TTH, who underwent tenderness protocol according to Diagnostic Criteria for TMD (DC/TMD) guidelines, was conducted followed by sEMG recording of temporalis and masseters. Pearson's correlation was performed to investigate the correlation between muscular activity and subjective pain scores.

Results

An overall moderate correlation between muscle tenderness and sEMG values (y = 1 + 1.2 · x; r² = 0.62; p < 0.0001), particularly in the temporalis, was observed. Segregation of data occurred according to tenderness and sEMG values. At the highest pain score, the mean sEMG absolute value was higher at the temporalis than the masseters.

Conclusions

Our study provides evidence that subjective pain perception can be objectively quantified at a magnitude proportional to pain severity. At greater tenderness scores, higher sEMG activity at the level of temporalis could help discriminate clinically prevalent TTH versus prevalent TMD. sEMG confirms to be an accurate tool to reliably objectify the subjective perception of pain. When combined with clinical evaluation and patients' symptoms, sEMG increases diagnostic sensitivity in the field of myo-type craniofacial pain disorders. This trial is registered with NCT02789085.

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.

Is there a difference in response to manual cranial bone tissue assessment techniques between participants with cervical and/or temporomandibular complaints versus a control group?

AIM

Manual cranial bone tissue techniques (CBTT) are used by physiotherapists as a tool for assessment and treatment of complaints in the craniocervical, face, and head regions. The goal of this study was to determine whether CBTT were able to discriminate between subjects with cervical and/or temporomandibular disorders (TMD) and a healthy group. In addition, the inter-rater reliability when applying CBTT was also investigated.

METHODS

A cross-sectional study was conducted and included 60 participants. Six standardized passive techniques were applied and judged for resistance, compliance, and sensory answer. In order to evaluate the inter-rater reliability of these techniques a cohort of participants was measured twice (by two evaluators) prospectively. A logistic regression model and Receiver Operating Curve (ROC) analyses were used to determining the discriminative validity of these techniques.

RESULTS

Logistic regression identified a significant difference for five techniques for resistance and/or compliance and/or the sensory answer between the groups. Based on the Area Under the Curve (AUC) analysis, the discriminative ability of the temporal rotation to distinguish between the groups was fair to good (for resistance AUC = 0.7775 and for compliance AUC = 0.8065). The highest agreement between the two assessors was for the resistance with occipital compression (73%) technique.

CONCLUSION

This study highlights that some of the CBTT could be potentially useful in distinguishing subjects with cervical and/or TMD from healthy subjects. Inter-rater reliability was moderate. CBTT could be potentially integrated in the examination of participants with complaints in the craniofacial region.

Painful temporomandibular disorder, sleep bruxism, anxiety symptoms and subjective sleep quality among military firefighters with frequent episodic tension-type headache. A controlled study

OBJECTIVE

To investigate associations of temporomandibular disorders (TMDs), bruxism, anxiety and sleep quality among military firefighters with frequent episodic tension-type headache (FETTH).

METHODS

The sample comprised two groups (80 individuals): controls (mean age 35.2 years) and study group (mean age 38.5 years). Headache was diagnosed in accordance with the ICHD-III. The Research Diagnostic Criteria for TMDs were used to classify the TMDs; bruxism was diagnosed in accordance with the International Classification of Sleep Disorders; anxiety was classified using the Beck Anxiety Inventory; and sleep quality was assessed using the Pittsburgh Sleep Quality Index. In the statistical models, we used a significance level of 95%.

RESULTS

Associations were found between participants with FETTH and TMDs (p < 0.001) and anxiety (p = 0.002).Poor quality of sleep (p = 0.687) and bruxism (p = 0.670) were not risk factors.

CONCLUSION

The study found that TMDs and anxiety among firefighters were associated with FETTH.

A Self-Reported Association between Temporomandibular Joint Disorders, Headaches, and Stress

AIMS AND OBJECTIVES

Temporomandibular joint disorder (TMD) is an umbrella term for a number of conditions in the area of the joint, temple, and masticatory system. Many of those with TMD also suffer from headaches and anxiety. The aims and objectives of this study were to determine if there exists an association between the Diagnostic Criteria of TMD (DC/TMD) symptom questionnaire and report of headaches as well as stress.

MATERIALS AND METHODS

A cross-sectional study was implemented via the use of the DC/TMD symptom questionnaire and the perceived stress scale (PSS). This was distributed conveniently among dental students in a multi-dental school setting in Riyadh, Saudi Arabia, and was completed by 152 dental students. Odds ratios, Chi-square, and their corresponding 95% confidence intervals are reported. Statistical significance was set at P ≤ 0.05.

RESULTS

Those who ticked yes for pain on the TMD pain screener for pain with chewing hard or tough food, pain on mouth opening and lateral excursion, and pain with jaw habits as parafunction were at an odds risk from twice to thrice as likely to experience headaches. Similarly, those with poor coping skills on the PSS were more likely to have headaches (P = 0.002). Likewise, positive answers on the screener and symptom questionnaire were relevant with higher stress scores on the PSS.

CONCLUSION

This study clarifies and reiterates the intertwined power of both stress and headaches; the former being a role player in TMD progression and the latter its product. TMD is unfortunately on the rise; it should not be brushed off as a nuisance. A multidisciplinary approach in diagnosis and treatment of both TMD and headaches by a team of orofacial pain specialist, neurologist, psychiatrist and/or psychologist, and physical therapists to untangle the deceiving presentation of both conditions would not only provide a more favorable prognosis but also improve cost and time expenditures.

Evaluation of Temporomandibular Disorders before and after Orthognathic Surgery: Therapeutic Considerations on a Sample of 76 Patients

Objectives:

Temporomandibular disorders may be associated with dental and facial malformations. The aim of this study is to record the prevalence of TMDs in patients scheduled for orthognathic surgery, reporting the development of TMDs and symptoms during the entire period of the treatment, and demonstrating the benefits of a team effort on this population.

Materials and Methods:

Assessment of temporomandibular status was performed using the RDC/TMD criteria at T0 (prior to orthodontic therapy), T1 (3 months after the surgery), and T2 post-therapeutic cycle (6 to 12 months postoperatively). A total of 76 participants were included in the study; all the patients underwent surgical treatment: 12 had bilateral sagittal split osteotomy, 6 with condylar position devices; 64 had Le Fort I + bilateral sagittal split osteotomy, and 15 with condylar position devices. Results were evaluated with a paired-sample t-test and segmentation analysis.

Results:

Forty-seven patients were affected by TMDs. At T0, 25 patients experienced TMJ pain, 27 had muscular pain, 31 suffered headaches, 42 had disc dislocation with reduction, and 5 were affected by disc dislocation without reduction. Thirty-five patients had occlusal signs of parafunctions, 8 reported tinnitus, and 7 dizziness. At T1, TMJ pain changed from 33.3% to 4.44%, muscular pain changed from 35.5% to 11.1%, headaches improved from 40% to 6.67%, and disc dislocation from 55.2% to 17.7%. Segmentation analysis highlighted improvement after therapy; 57 patients were considered recovered, 14 improved, none were considered stable, whereas 5 patients demonstrated some worsening, 3 of whom had not presented disc dislocation before surgery. At T2, 71 patients were considered completely recovered or improved.

Conclusions:

Our data indicates beyond any doubt that both functional status and pain levels related to TMDs can be significantly improved with a multi-disciplinary approach. We concluded that surgeon's intervention need to be modified in the presence of presurgical TMDs.

Classification: The key to understanding facial pain

It is indisputable that the global scientific advances in headache research, be it bench or bedside, have benefited enormously from the operational diagnostic criteria published in 1988. Today, this classification system is indispensable. The reason for this success is a low inter-rater variability. In general, orofacial pain conditions are less well characterised – with the noticeable exemption of temporomandibular disorder pain. Tremendous work has been put into changing this, and significant progress has been achieved – in particular, in terms of the clinical implications and overriding conceptual models for oro-facial pain. Scientific classifications have only one goal: To provide a scientific agreement about the main features of an object of research and a scientific consensus regarding the name. The main significance is not the fact that a good classification offers a detailed and accurate image of the reality. If we want to overcome the obstacles of different competing classification systems, we need to overcome specialisation borders. The key to success is to understand that such a definition does not mirror all possible clinical facets of a given pain condition but is simply a convention – that is, a consensus on a word used for a pain condition. Simply speaking, a classification creates a common language to be used by more than one profession. It will be crucial to define any given pain condition as precisely and rigid as possible, in order to ensure a homogenous population. Only this ensures a low inter-rater variability, which consequently allows combining and comparing research on a population across different professional settings. This is not easy for chronic facial pain without verifiable morphological cause or structural lesions, as these syndromes are often rather featureless. The new IASP classification of chronic pain is a big step forward to a better characterisation of such conditions, and will trigger future work on a new and operationalised classification of oro-facial pain.

Evaluation of lateral pterygoid muscles in painful temporomandibular joints by signal intensity on fluid-attenuated inversion recovery images

OBJECTIVES

Pathological changes of the lateral pterygoid muscle (LPM) have been investigated using various modalities, including magnetic resonance (MR) imaging and electromyography. Fluid-attenuated inversion recovery (FLAIR) is an MR sequence that we hypothesized can be used to evaluate abnormalities of the LPM. The purpose of this study was to analyze the FLAIR signal intensity of the LPM in painful temporomandibular joints (TMJs) and investigate the pathological changes of the muscle.

METHODS

The study was based on 149 TMJs of 77 patients who were referred for MR imaging of the TMJ. Patients rated their degree of pain during chewing and mouth opening using a visual analog scale (VAS). Regions of interest were placed over the superior and inferior heads of the LPM and gray matter on FLAIR sagittal images. Using the signal intensity of gray matter as a reference, the signal intensity ratio (SIR) of the LPM was calculated. Spearman's rank-correlation coefficient was used to analyze the correlation between the SIR and the VAS score (p < 0.05).

RESULTS

A significant correlation was present between the SIR on FLAIR images and the VAS score.

CONCLUSIONS

These results suggest that the FLAIR signal intensity of the superior and inferior heads of the LPM significantly increases as TMJ pain becomes more severe. Thus, FLAIR could be useful in assessing the relationship between the MR signals of the LPM and clinical symptoms.

Influence of culture on pain comorbidity in women with and without temporomandibular disorder-pain

Evidence on cultural differences in prevalence and impact of common chronic pain conditions, comparing individuals with temporomandibular disorders (TMD) versus individuals without TMD, is limited. The aim was to assess cross-cultural comorbid pain conditions in women with chronic TMD pain. Consecutive women patients (n = 122) with the index condition of chronic TMD pain diagnosed per the research diagnostic criteria for TMD and TMD-free controls (n = 121) matched for age were recruited in Saudi Arabia, Italy and Sweden. Self-report questionnaires assessed back, chest, stomach and head pain for prevalence, pain intensity and interference with daily activities. Logistic regression was used for binary variables, and ancova was used for parametric data analysis, adjusting for age and education. Back pain was the only comorbid condition with a different prevalence across cultures; Swedes reported a lower prevalence compared to Saudis (P < 0·01). Saudis reported higher prevalence of work reduced >50% due to back pain compared to Italians or Swedes (P < 0·01). Headache was the most common comorbid condition in all three cultures. The total number of comorbid conditions did not differ cross-culturally but were reported more by TMD-pain cases than TMD-free controls (P < 0·01). For both back and head pain, higher average pain intensities (P < 0·01) and interference with daily activities (P < 0·01) were reported by TMD-pain cases, compared to TMD-free controls. Among TMD-pain cases, Italians reported the highest pain-related disability (P < 0·01). Culture influences the associated comorbidity of common pain conditions. The cultural influence on pain expression is reflected in different patterns of physical representation.

Temporomandibular disorders: Old ideas and new concepts

Background Temporomandibular disorders (TMD) is an umbrella term for pain and dysfunction involving the masticatory muscles and the temporomandibular joints (TMJs). TMD is the most common orofacial pain condition. Its prominent features include regional pain in the face and preauricular area, limitations in jaw movement, and noise from the TMJs during jaw movements. TMD affects up to 15% of adults and 7% of adolescents. Chronic pain is the overwhelming reason that patients with TMD seek treatment. TMD can associate with impaired general health, depression, and other psychological disabilities, and may affect the quality of life of the patient. Assessment Evaluations indicate that the recently published Diagnostic Criteria for TMD (DC/TMD) are reliable and valid. These criteria cover the most common types of TMD, which include pain-related disorders (e.g., myalgia, headache attributable to TMD, and arthralgia) as well as disorders associated with the TMJ (primarily disc displacements and degenerative disease). As peripheral mechanisms most likely play a role in the onset of TMD, a detailed muscle examination is recommended. The persistence of pain involves more central factors, such as sensitization of the supraspinal neurons and second-order neurons at the level of the spinal dorsal horn/trigeminal nucleus, imbalanced antinociceptive activity, and strong genetic predisposition, which also is included in DC/TMD. Conclusion The etiology is complex and still not clearly understood, but several biological and psychosocial risk factors for TMD have been identified. Several studies indicate that patients with TMD improve with a combination of noninvasive therapies, including behavior therapy, pharmacotherapy, physical therapy, and occlusal appliances. More stringently designed studies, however, are needed to assess treatment efficacy and how to tailor treatment to the individual patient.