General health status and incidence of first-onset temporomandibular disorder: the OPPERA prospective cohort study

Rome Foundation Working Team Report on overlap in disorders of gut-brain interaction

In patients with disorders of gut-brain interaction (DGBI), overlapping non-gastrointestinal conditions such as fibromyalgia, headaches, gynaecological and urological conditions, sleep disturbances and fatigue are common, as is overlap among DGBI in different regions of the gastrointestinal tract. These overlaps strongly influence patient management and outcome. Shared pathophysiology could explain this scenario, but details are not fully understood. This overlap has been shown to be of great relevance for DGBI. In addition, symptoms considered to be caused by a DGBI could have a detectable organic cause, and in patients with a diagnosed organic gastrointestinal disease, symptoms not clearly explained by the pathology defining this organic disease are common. Thus, the aims of this Rome Foundation Working Team Report were to review the literature on overlapping conditions among patients with paediatric and adult DGBI and, based on the available epidemiological and clinical evidence, make recommendations for the current diagnostic and therapeutic approach, and for future research. Specifically, we focused on other DGBI in the same or different gastrointestinal anatomical region(s), DGBI overlap with organic bowel diseases in remission, and DGBI overlap with non-gastrointestinal, non-structural conditions.

Association Between Temporomandibular Disorders and Irritable Bowel Syndrome: A Scoping Review

Temporomandibular disorders (TMDs) encompass various clinical conditions associated with the temporomandibular joint (TMJ) and the masticatory muscles. TMD symptoms include pain in the orofacial region, restricted or altered mandibular movement, and sounds associated with the temporomandibular joint (TMJ). This condition adversely affects quality of life, social functioning, and daily activities, and may also contribute to widespread pain syndromes and comorbidities, including irritable bowel syndrome (IBS). IBS is a common chronic functional disorder of the lower gastrointestinal tract, characterized by recurrent abdominal pain associated with impaired bowel symptoms. Previous studies indicate an association between TMD and IBS. This scoping review examined the correlation between TMD and IBS concerning their pathology, frequency, and severity, and the potential similarities in how the nervous and endocrine systems influence them. PubMed, SCOPUS, Web of Science, and Google Scholar search engines were utilized to identify suitable studies for this article. Following the application of selection criteria, a total of 58 clinical papers met the eligibility requirements for inclusion in the systematic review. Research showed that both conditions significantly enhance the development of one another and have mutual comorbidities. Both ailments were proven to modify central nervous system processing, leading to high comorbidity in patients. Combining dental and gastroenterological treatments, including a simultaneous therapeutic approach, can significantly enhance patients' quality of life, but further research is needed for a holistic approach.

Identifying phenotypes in persons with temporomandibular disorders, using latent class analyses: Temporomandibular disorders and phenotypes

BACKGROUND

The heterogeneity of persons with temporomandibular disorders (TMD) and the lack of effective treatments have called for a biopsychosocial model and the development of a more personalised treatment approach. Emphasis on phenotypes might be a beneficial approach.

OBJECTIVE

Identifying phenotypes among persons with TMD using potential prognostic factors, including personal characteristics and responses to clinical tests. Additionally, examining the distribution of TMD diagnoses within the identified phenotypes.

METHODS

A cross-sectional study including 208 persons (85% females) seeking physiotherapy for problems in the temporomandibular area. All participants were examined clinically and answered questionnaires electronically. The phenotypes were identified using latent class analysis based on seven potential prognostic factors selected within pain, function and psychological domains. Table analysis was used to explore the distribution of TMD diagnoses within the identified phenotypes.

RESULTS

Most participants fit into one of three identified phenotypes. Phenotype 1 (32%) was characterised by functional disability, low psychosocial scores and low risk for developing chronicity and future work disability; Phenotype 2 (29%) by parafunctional habits, low psychosocial score and seeking treatment to reduce pain; and Phenotype 3 (39%) by high levels of mental distress, fear avoidance and a large risk of future work disability. Intra-articular disorders dominated Phenotype 1, myalgia and TMD-related headache Phenotype 2, while Phenotype 3 included all the different TMD diagnoses.

CONCLUSION

The knowledge about the three identified phenotypes might be useful for clinicians treating persons with TMD and for the development of preventive strategies and more personalised treatment.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Prevalence of psychosocial findings and their correlation with TMD symptoms in an adult population sample

BACKGROUND AND AIM

Some studies suggested an association between Temporomandibular Disorders (TMD) and psychosocial status, but most of them are focused on samples of patients looking for treatment or present limits of sample representativeness. The aim of the present study was to evaluate the psychosocial status in a large sample of adult population, further than to assess its association to TMD symptoms, oral behaviours, and self-reported facial trauma.

RESULTS

the study sample included 4299 subjects older than 18 years randomly recruited from general population in public spaces during their daily life (1700 Males, 2599 Females mean ± SD age = 40.4 ± 18.1). Psychosocial status and pain-related disability were assessed by means of Patient Health Questionnaire 4 (PHQ-4) and Graded Chronic Pain Scale (GCPS). TMD symptoms were assessed by RDC/TMD and validated screening tools for TMD pain. Oral Behaviours Checklist was used to investigate on oral behaviours. Logistic regression model was used to evaluate the association of the psychosocial status, TMD symptoms, trauma, and oral behaviours. The association was tested using both univariate and multivariate models. The PHQ4 evaluation showed a severe impairment in 4.6% of our sample, moderate in 18.8% and mild in 32.5%. We found a Characteristic Pain Intensity (CPI) level and Interference Score greater that 30 respectively in 36.2% and 22.2% of the study sample. The GCPS status revealed a high disability with severe limitation in 2.5% of the sample, high disability with moderate limitation in 7.0%, low disability high pain intensity in 7.4% and low disability low pain intensity in 37.8%. Anxiety and depression's levels were significantly associated with gender, TMD pain, coexistence of TMD Pain and sound, and oral behaviours. GCPS status was significantly associated with age, TMD Pain, coexistence of TMD pain and sound, trauma, and oral behaviours.

CONCLUSIONS

In the general population, psychosocial impairment is associated to TMD pain, female gender, and report of oral behaviours. Hence, in adults with TMD accompanied by pain, psychosocial status should also be evaluated.

Hypervigilance to pain and sleep quality are confounding variables in the infrared thermography examination of the temporomandibular joint and temporal and masseter muscles

OBJECTIVES

Verify whether hypervigilance to pain (HP) and sleep quality (SQ) are confounding variables in the infrared thermography (IT) examination of the temporomandibular joint and temporal and masseter muscles.

METHODS

A cross-sectional and analytical study was conducted, collecting HP and SQ data from 80 participants without temporomandibular disorders (TMD), performing their IT and another 40 participants with TMD. For the selection of participants with and without TMD, the TMD Pain Screener questionnaire and axis I of the Diagnostic Criteria for Temporomandibular Disorders were applied. SQ was verified using the Pittsburgh Sleep Quality Index (PSQI) questionnaire. For the HP assessment the Pain Vigilance and Awareness Questionnaire (PVAQ) was applied. And the IT was performed through a FLIR infrared sensor camera, model T650 Infrared.

RESULTS

No significant correlations were found between SQ and the temperatures of the areas of interest (P > .05), and regarding HP, a statistically significant positive correlation was found with the dimensionless (ρ = 0.289) and non-dimensionless (ρ = 0.223) asymmetries of temporal muscle temperatures. In the temperature comparisons between the participants without TMD and the participants with TMD, significant differences were found (P < .05), also when the group without TMD was controlled according to both HP and SQ (P < .05), with higher temperatures found in the TMD group.

CONCLUSIONS

HP and SQ can be considered confounding variables in IT examination of the temporomandibular region.

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.

Stratification of orthognathic surgery patients for painful TMD and associated factors

The prevalence of temporomandibular disorder (TMD) in patients with (dentofacial deformities) DFD is high, indicating a multifaceted relationship between physical and psychosocial factors.

OBJECTIVE

To identify clusters of patients with DFD based on variables related to TMD, psychological aspects, somatization, oral habits, and sleep.

METHOD

Ninety-two patients with DFD were evaluated before orthognathic surgery according to demographic data, facial profile, presence of painful TMD (DC/TMD), psychological aspects, oral habits, comorbidities, substance use, and sleep quality.

RESULTS

Eighty-six individuals comprised the final sample. The K-means cluster analysis identified two distinct but internally similar groups. One called "Vulnerable" with a higher prevalence of muscular TMD and associated factors with 43 (50%) participants, and another with 43 (50%) participants, called "Adaptive" with a lower prevalence of these variables (P<.01). The determining variables were signs and symptoms of anxiety and somatization, awake bruxism and self-reported sleep quality. The presence of arthralgia, comorbidities, or smoking did not influence the formation of the groups. The clusters were tested with gender, age, facial profile, maxillary excess, and deficiency. Only females were associated with the vulnerable group (P=.015). These results highlight the importance of multidimensional assessment of patients with DFD. The stratification of these individuals can help with personalized treatment, targeting specific strategies for each group, such as behavioral interventions and referrals to a multidisciplinary team.

Clustering profiles of demographic and clinical characteristics and the oral health impact of individuals with temporomandibular disorders

OBJECTIVE

To identify profiles of demographic, clinical, and oral health impact characteristics of individuals with temporomandibular disorder (TMD).

METHODS

Four hundred ninety-six TMD patients (260 females) and 30 young controls were included. Sociodemographic, clinical, and Oral Health Impact Profile (OHIP-14) data were gathered and analyzed by Cluster, ANOVA, and regression analyses.

RESULTS

Three clusters were identified: "Pain and depression symptoms" with participants with higher pain, depression, and OHIP-14 scores (59% females); "Chronic diseases" included older participants with current chronic diseases and medical treatment; "Healthier individuals" included younger individuals with lower chronic diseases, pain, and depression frequencies, whose OHIP-14 scores did not differ from controls (p = 0.079). OHIP-14 scores were predicted by age, pain, and depression.

CONCLUSION

Distinct profiles of individuals with TMD were identified, emphasizing the complex interactions between coping ability, general health, and psychosocial aspects that must be monitored.

Randomized controlled trial of digital therapeutics for temporomandibular disorder: A pilot study

OBJECTIVES

Temporomandibular disorder (TMD) is a common condition that affects the temporomandibular joint (TMJ) and the muscles of the jaw, resulting in pain and dysfunction. TMD is affected by both behavioral and psychological factors. Digital therapeutics (DTx) can exert therapeutic effects by controlling behavioral factors through the delivery of appropriate interventions. Here, we report an open-label randomized control trial to evaluate the efficacy of DTx for TMD.

METHODS

We recruited 40 participants diagnosed with TMD. Participants were randomly divided into an intervention group (DTx use, n = 20) and a control group (n = 20). The intervention group received the usual treatment process for TMD in addition to the use of the DTx. The control group received the usual treatments only. Patients in both groups were followed up for 3-4 weeks, and outcome data were collected and analyzed.

RESULT

The intervention group showed a significant reduction in pain scores as measured by the numerical rating scale (NRS) (p = 0.016). Additionally, the intervention group showed a statistically significant increase in maximal mouth opening compared to the control group (p = 0.0079). However, there were no significant differences in improvement in the Jaw Functional Limitation Scale, Oral Behavior Checklist, and Patient Health Questionnaire-4 between the two groups (p = 0503, = 0.820, and = 0.943, respectively).

CONCLUSION

This RCT reveals DTx potential in TMD, showing pain and mouth opening improvements with conventional treatment. But no significant changes were noted in other outcomes. The findings advocate for more extensive, long-term research to solidify DTx's role in TMD management.

CLINICAL SIGNIFICANCE

This research underlines DTx potential to improve pain outcomes in TMD therapy, reinforcing its value as a complementary treatment modality.

Elevated pain sensitivity is associated with reduced rapid eye movement (REM) sleep in females with comorbid temporomandibular disorder and insomnia

OBJECTIVE

Patients with chronic pain disorders, including Temporomandibular Disorders (TMDs) endorse high levels of sleep disturbances, frequently reporting reduced sleep quality. Despite this, little is known about the effect that daytime pain has on the microstructure and macro-architecture of sleep. Therefore, we aimed to examine the extent to which daytime pain sensitivity, measured using quantitative sensory testing (QST), is associated with objective sleep parameters the following night, including sleep architecture and power spectral density, in women with TMD.

METHODS

144 females with myalgia and arthralgia by examination using the Diagnostic criteria for TMD completed a comprehensive QST battery consisting of General Pain Sensitivity, Central Sensitization Index, and Masseter Pressure Pain Threshold assessments. Polysomnography was collected the same night to measure sleep architecture and calculate relative power in delta, theta, alpha, sigma, and beta power bands.

RESULTS

Central Sensitization (B = -3.069, P = .009), General Pain Sensitivity Indices (B = -3.069, P = .007), and Masseter Pain Pressure Threshold (B = 0.030, P = .008) were significantly associated with lower REM% both before and after controlling for covariates. Pain sensitivity measures were not significantly associated with relative power in any of the spectral bands nor with any other sleep architectural stages.

CONCLUSIONS

Our findings demonstrate that higher generalized pain sensitivity, masseter pain pressure threshold, as well as central sensitization were associated with a lower percentage of REM in participants with myofascial pain and arthralgia of the masticatory system. These findings provide an important step toward understanding the mechanistic underpinnings of how chronic pain interacts with sleep physiology.

Genetically predicted major depression causally increases the risk of temporomandibular joint disorders

Objective

Observational studies have reported that mental disorders are comorbid with temporomandibular joint disorder (TMD). However, the causal relationship remains uncertain. To clarify the causal relationship between three common mental illnesses and TMD, we conduct this Mendelian Randomization (MR) study.

Methods

The large-scale genome-wide association studies data of major depression, bipolar disorder and schizophrenia were retrieved from the Psychiatric Genomics Consortium. The summary data of TMD was obtained from the Finn-Gen consortium, including 211,023 subjects of European descent (5,668 cases and 205,355 controls). The main approach utilized was inverse variance weighting (IVW) to evaluate the causal association between the three mental disorders and TMD. Five sensitivity analyses including MR-Egger, Maximum Likelihood, Weighted median, MR. RAPS and MR-PRESSO were used as supplements. We conducted heterogeneity tests and pleiotropic tests to ensure the robustness.

Results

As shown by the IVW method, genetically determined major depression was associated with a 1.65-fold risk of TMD (95% CI = 1.10-2.47, p < 0.05). The direction and effect size remained consistent with sensitivity analyses. The odds ratios (ORs) were 1.51 (95% CI = 0.24-9.41, p > 0.05) for MR-Egger, 1.60 (95% CI = 0.98-2.61, p > 0.05) for Weighted median, 1.68 (95% CI = 1.19-2.38, p < 0.05) for Maximum likelihood, 1.56 (95% CI = 1.05-2.33, p < 0.05) for MR. RAPS, and 1.65 (95% CI = 1.10-2.47, p < 0.05) for MR-PRESSO, respectively. No pleiotropy was observed (both P for MR-Egger intercept and Global test >0.05). In addition, the IVW method identified no significant correlation between bipolar disorder, schizophrenia and TMD.

Conclusion

Genetic evidence supports a causal relationship between major depression and TMD, instead of bipolar disorder and schizophrenia. These findings emphasize the importance of assessing a patient's depressive status in clinical settings.

Temporomandibular disorder patients with excessive daytime sleepiness present greater pain intensity and reduced jaw function

BACKGROUND

Sleep disorders are associated with temporomandibular disorders (TMDs). Limited studies have focused on excessive daytime sleepiness (EDS) and its impact on jaw functions in TMD patients.

OBJECTIVE

The aim of the present investigation was to identify the impact of EDS on pain and jaw function in TMD patients.

METHODS

A total of 338 TMD patients (50 males and 288 females) was included. The Epworth Sleepiness Scale (ESS) was used to classify patients into EDS group (score ≥ 10) and non-EDS group (score < 10). The Jaw Functional Limitation Scale 8-item (JFLS-8) was used to assess the severity of jaw dysfunction. Pain intensity was evaluated using the Visual Analogue Scale (VAS). Anxiety and depression were evaluated using the Generalised Anxiety Disorder 7-item (GAD-7) and the Patient Health Questionnaire 9-item (PHQ-9). All included patients were diagnosed with pain-related TMD (PT), intra-articular TMD (IT) or combined TMD (CT).

RESULTS

Compared with non-EDS patients, EDS patients exhibited more severe jaw dysfunction, greater pain intensity and higher PHQ-9 scores (p < .05). Multivariate analyses showed that EDS (B = 3.69), female gender (B = 3.69), and elevated GAD-7 score (B = 0.73) were significantly associated with an increased score on the JFLS-8 (p < .05). Moreover, bivariate logistic regression analysis indicated a significant relationship between EDS and PT (OR = 2.70, p = .007).

CONCLUSION

The presence of EDS was more closely related to PT, but the causal relationship between them needs to be further confirmed. More concern and intervention to alleviate poor sleep quality might be highlighted during the treatment of TMD, especially PT subtype.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Age and sex differences in comorbidities in adult temporomandibular disorders: A cross-sectional study using Korea National Health and Nutrition Examination Survey (KNHANES)

OBJECTIVES

To investigate the relationship between Temporomandibular disorder (TMD) and associated comorbidities in groups matched according to age and sex.

METHODS

Using data from the cross-sectional fifth Korea National Health and Nutrition Examination Survey (KNHANES). Of the 25,534 eligible KNHANES, 17,762 adults aged ≥19 years who responded to survey questionnaire on TMD and comorbidities. Subjects were classified into eight groups according to age and sex. Logistic regression analyses were performed to evaluate the association between TMD and comorbidities according to age and sex.

RESULTS

Of the enrolled participants, 2,107 (11.86%) complained of ≥1 TMD symptoms. In all groups, odds ratios (ORs) for prevalence of TMD were >1 in those with tinnitus. Rhinitis was closely associated with TMD in 6 groups. ORs for TMD with comorbidities according to age and sex were as follows: hypertension, men aged 50-64 years (OR 0.62; CI 0.41-0.94); ischemic heart disease, men aged 35-49 years (4.38; 1.54-12.47); osteoarthritis, women aged 50-64 years (1.38; 1.03-1.86); diabetes mellitus, men aged 35-49 years (0.21; 0.05-0.88); depression, men aged 50-64 years (1.68; 1.00-2.83), women aged 35-49 years (1.39; 1.05-1.85) and women aged 65-80 years (2.01; 1.46-2.77); migraine, men aged 50-64 years (1.60; 1.14-2.25), women aged d35-49 years (1.44; 1.14-1.81) and women aged 35-49 years (1.43; 1.07-1.90); cold hypersensitivity in the hands and feet, men aged 19-34 years (1.64; 1.05-2.58), men aged 35-49 years (1.68; 1.04-2.70), men aged 65-80 years (1.74; 1.09-2.75) and women aged 35-49 years (1.45; 1.15-1.84); olfaction disorder, men aged 50-64 years (2.49; 1.39-4.43); voice disorder, men aged 50-64 years (2.25; 1.28-3.96) and women aged 65-80 years (1.69; 1.09-2.63).

CONCLUSIONS

This study confirmed that the types and effects of comorbidities related to prevalence of TMD may differ according to the patient's age and sex and this result will increase the predictability of the onset of TMD.

Prevalence of Temporomandibular Disorders Based on a Shortened Symptom Questionnaire of the Diagnostic Criteria for Temporomandibular Disorders and Its Screening Reliability for Children and Adolescents Aged 7-14 Years

The prevalence and adequacy of diagnostic approaches for temporomandibular disorders (TMD) in children and adolescents are still matters of debate. This study aimed to determine the prevalence of TMD and oral habits in children and adolescents aged 7-14 years and evaluate the consistency between self-reported TMD symptoms and clinical findings using a shortened Axis I of Diagnostic Criteria for TMD (DC/TMD). Children (aged 7-10) and adolescents (aged 11-14) of both sexes were invited to participate in this study (n = 1468). Descriptive statistics for all observed variables and Mann-Whitney U-Tests for the clinical examination were performed. A total of 239 subjects participated in the study (response rate 16.3%). The self-reported prevalence of TMD was found to be 18.8%. The most frequently reported oral habit was nail biting (37.7%), followed by clenching (32.2%) and grinding (25.5%). Self-reported headache increased with age, while clenching and grinding decreased. Based on the answers to the DC/TMD Symptom Questionnaire, subgroups of asymptomatic and symptomatic participants (n = 59; 24.7%) were established and randomly selected for the clinical examination (f = 30). The shortened Symptom Questionnaire showed a sensitivity of 0.556 and a specificity of 0.719 for pain during the clinical examination. Although the Symptom Questionnaire exhibited high specificity (0.933), its sensitivity (0.286) for temporomandibular joint sounds was low. Disc displacement with reduction (10.2%) and myalgia (6.8%) were the most common diagnoses. In conclusion, the self-reported prevalence of TMD in children and adolescents in this study was comparable to that reported in the literature for adults. However, the accuracy of the shortened Symptom Questionnaire as a screening tool for TMD-related pain and jaw sounds in children and adolescents was found to be low.

The Longitudinal Relationship between Jaw Catching/Locking and Pain

Orofacial pain and joint-related dysfunction can negatively affect daily jaw function. A common cause for limitations in jaw movements is joint-related dysfunction such as various forms of catching and locking. However, knowledge is limited regarding the development and natural course of joint-related jaw dysfunction and its relationship to the onset and course of orofacial pain. Therefore, the aim was to evaluate the incidence, prevalence, and gender differences in jaw catching/locking over time and in relation to orofacial pain in the general population. Data from 3 validated screening questions on orofacial pain and jaw catching/locking were collected from all routine dental checkups in the Public Dental Health Services in Västerbotten, Sweden, from 2010 to 2017. Logistic generalized estimating equation was used to account for repeated observations and Poisson regression for incidence analysis. In total, 180,308 individuals (aged 5-104 y) were screened in 525,707 dental checkups. In 2010, based on 37,647 individuals, the prevalence of self-reported catching/locking was higher in women than in men (3.2% vs. 1.5%; odds ratio, 2.11; 95% confidence interval [CI], 1.83-2.43), and this relationship and magnitude remained similar throughout the study period. The annual incidence rate was 1.1% in women and 0.5% in men. Women were at a higher risk than men for reporting both first onset (incidence rate ratio [IRR], 2.29; 95% CI, 2.11-2.49) and persistent (IRR, 2.31; 95% CI, 2.04-2.63) catching/locking. For the onset subcohort (n = 135,801), an independent onset of orofacial pain or jaw catching/locking exclusively was reported by 84.1%, whereas a concurrent onset was reported by 13.4%. Our findings of higher incidence, prevalence, and persistence in women than in men indicate that the gender differences seen for orofacial pain are evident also for jaw catching/locking. The findings also suggest independent onset of self-reported catching/locking and orofacial pain, which reinforces the pathophysiological differences between these conditions.

Pathogenesis and Differential Diagnosis of Temporomandibular Joint Disorders

Temporomandibular disorders (TMDs) are an umbrella term including disorders of the temporomandibular joint and muscles of the masticatory system. They are the most common nonodontogenic cause of pain in the orofacial region. A clear understanding of various conditions, underlying mechanisms, clinical presentation, and examination skills is required to effectively diagnose and manage these patients.

How negative and positive constructs and comorbid conditions contribute to disability in chronic orofacial pain

BACKGROUND

Temporomandibular disorders (TMD) symptoms develop into chronic pain for some patients, but the reasons for this are unclear. Psychosocial factors and chronic overlapping pain conditions are believed to contribute to the development of pain-related disability. We examined the role of jaw function, negative and positive psychological factors and chronic overlapping pain conditions (COPCs) on pain-related disability whilst controlling for demographic variables.

METHODS

We collected demographics, medical and psychosocial history and the Graded Chronic Pain Scale, a measure of pain intensity and pain interference from 400 participants with chronic TMD. Structural equation modelling was used to assess a model of COPCs and the latent variables of psychological unease (pain catastrophizing, somatic symptoms and negative affect), positive valence factors (optimism and positive affect), jaw function (chewing, opening and expression limitation) and pain-related disability (pain intensity and pain interference) whilst controlling for demographic variables.

RESULTS

We achieved good fit of a parsimonious model (root-mean-square error of approximation = 0.063 [90% CI] [0.051-0.075]), comparative fit index = 0.942, standard root-mean-square residual = 0.067. Jaw function was the strongest latent variable predictor, followed by psychological unease and COPCs suggesting resources focused on improving joint function, psychosocial support and management of COPCs will improve pain-related disability in TMDs.

CONCLUSIONS

These findings not only increase the body of knowledge related to TMD clinical phenotypes but also, have a translational impact in further supporting the potential value of targeting physical therapy such as jaw exercise along with psychological interventions as multidisciplinary nonpharmacological therapeutic solutions.

Association between Sleep Disorders and Sleep Quality in Patients with Temporomandibular Joint Osteoarthritis: A Systematic Review

Background: Osteoarthritis (OA) is a leading cause of disability, the most common form of chronic disease in the temporomandibular joint (TMJ), and the most severe disease type of temporomandibular disorders (TMD). The etiology of TMD is multifactorial, considering parafunctional habits, sleep bruxism, or sleep disturbance as common factors. Insomnia and apnea are the two most frequent forms of sleep disorders in TMD patients. Due to this, the objective of this systematic review was to highlight whether there is currently scientific evidence in the literature describing that patients with temporomandibular joint osteoarthritis (TMJ-OA) are associated with increased sleep disorders or impaired sleep quality. Methods: This systematic review was completed in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) statement and was registered with PROSPERO prior to completion of the main search. Original observational studies that analyze the association of sleep disorders and sleep quality in patients with TMJ-OA were included in the present review. Results: 770 studies were screened by abstract and title according to inclusion and exclusion criteria, and finally, 7 articles were included in the qualitative synthesis and a total of 772 patients diagnosed with TMJ-OA. Conclusions: There is insufficient evidence to indicate that patients with TMJ OA are associated with increased sleep disorders or poorer sleep quality.

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.

Self-Medication Profile of Adult Patients with Temporomandibular Disorders in Southeast Brazil

BACKGROUND

Patients with temporomandibular disorder (TMD) often have orofacial pain and may use medication without professional prescription. Self-medication and inappropriate drug intake may cause serious health problems. This cross-sectional study evaluated the self-medication profile of TMD patients, the most used medications and their effect, and the relation between self-medication and socioeconomic factors.

METHODS

A non-representative sample (n=358) consisted of consecutive adult patients seeking TMD treatment in specialized referral centers for orofacial pain of two universities in São Paulo city, Brazil. A standardized questionnaire was used to collect the study variables before the TMD treatment: self-medication history, TMD pain intensity, sex, age, ethnicity, marital status, schooling and socioeconomic levels. Data were analyzed by descriptive statistics, chi-square test, and logistic regression models at the 0.05 significance level.

RESULTS

Almost 60% of 358 TMD patients reported self-medication. Patients with severe TMD were 4.7 times more likely to self-medicate when compared to patients with low TMD intensity (O=5.7; 95% CI=2.4; 13.3; P=0.043), as well as female patients were 30% more likely to self-medicate compared to male patients (OR=2.3; 95% CI=1.1; 5.1; P<0.001). The other independent variables were not associated with self-medication. The frequencies of moderate and severe TMD in women were larger than in those in men (P<0.001). Analgesics and anti-inflammatory drugs were the most used medications. Regarding medication efficacy, 82% of patients reported some improvement after use, but 9% reported side-effect sickness.

CONCLUSION

Self-medication is common among TMD patients attending specialized clinics, and this inappropriate practice is more likely to occur in women and in patients with severe signs and symptoms of TMD.

Effects of Prosthetic Rehabilitation on Temporomandibular Disorders: Protocol for a Randomized Controlled Trial

Background

Loss of teeth or occlusal imbalance is one of the proposed dental risk factors for temporomandibular disorders (TMDs). Losing some non–free-end teeth cause the original occluding tooth/teeth to supraerupt from the original upright position and causes neighboring tooth/teeth to shift in an angle, causing biomechanical imbalance on the mandible. Based on these sequelae, rehabilitation of missing teeth is the first step in managing TMD in edentulous patients. Even though the prevalence of TMD in association with edentulism and in rehabilitated patients has been increasing, proper guidelines for the management of such cases have not been established. This study describes the protocol to analyze the effect of prosthetic rehabilitation on patients with TMD.

Objective

This study aims to determine the effectiveness of prosthetic rehabilitation in the reduction of pain in edentulous patients with TMD and to determine the effect of the span of edentulism, the number of quadrants involved, pathological migration, the type of Kennedy classification, and the prosthetic status on temporomandibular joint dysfunction signs and symptoms.

Methods

In this randomized controlled trial, 300 patients diagnosed with TMD will be grouped into one of the three interventional groups based on the type of their edentulous state. The interventional groups are (1) partially edentulous arch: Kennedy Class I and II (prosthetic rehabilitation without splint); (2) partially edentulous arch: Kennedy Class III and IV (prosthetic rehabilitation with a splint); and (3) completely edentulous arches (prosthetic rehabilitation without splint). All three of the mentioned interventional groups have corresponding control groups that will receive symptomatic treatment and comprehensive counseling. The measured primary outcomes are pain and electromyogram, and the secondary outcomes include pain drawing, Graded Chronic Pain Scale, Jaw Functional Limitation Scale, Oral Behaviours Checklist, depression, physical symptoms, and anxiety. The outcome measurements will be recorded at baseline and at the end of 24 hours, 7 days, 28 days, and 3 months.

Results

Ethical approval was obtained from the Institutional Review Board of Amrita Institute of Medical Sciences, Kochi, India. Study participants’ recruitment began in May 2021 and is expected to conclude in March 2023. This clinical trial protocol was developed based on the SPIRIT (Standard Protocol Items: Recommendations for Interventional Trials) 2013 Statement.

Conclusions

The purpose of this study is to gather data on prosthetic rehabilitation as a treatment for TMD. Obtaining this goal will aid in the development of evidence-based therapy protocols for prosthetic rehabilitation in TMD management.

Trial Registration

Clinical Trials Registry - India CTRI/2020/06/026169; http://ctri.nic.in/Clinicaltrials/pdf_generate.php?trialid=42381

International Registered Report Identifier (IRRID)

DERR1-10.2196/33104

Review article: Physical and psychological comorbidities associated with irritable bowel syndrome

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders encountered by physicians in primary and secondary care. Patients with IBS commonly present with various extraintestinal complaints, which account for a substantial clinical and economic burden. The common extraintestinal comorbidities associated with IBS include anxiety, depression, somatisation, fibromyalgia, chronic fatigue syndrome, chronic pelvic pain, interstitial cystitis, sexual dysfunction and sleep disturbance. The presence of comorbidity in IBS poses a diagnostic and therapeutic challenge with patients frequently undergoing unnecessary investigations and interventions, including surgery. This review discusses the different physical and psychological comorbidities associated with IBS, the shared pathophysiological mechanisms and potential management strategies.

Acute and Chronic Temporomandibular Disorder Pain: A critical review of differentiating factors and predictors of acute to chronic pain transition

AIMS

The aims of this critical review were to: (i) assess the factors that differentiate acute from chronic temporomandibular disorders (TMD) pain; (ii) assess the risk factors associated with the transition from acute to chronic TMD pain; and (iii) summarize and appraise the studies.

METHOD

The databases used were MEDLINE, Embase, and Cochrane Database of Systematic Reviews. Eligible studies included articles comparing acute to chronic TMD pain, and cohort studies assessing the risk factors implicated in the transition from acute to chronic TMD pain.

RESULTS

Seven articles were selected: one case-control study, three cross-sectional studies, and three cohort studies. These studies found that psychological factors were more common in chronic than acute TMD pain patients; however, these factors did not increase the transition risk in the multivariable model. Myofascial and baseline pain intensity were associated with the transition from acute to chronic TMD pain at a 6-month follow-up. Due to methodological weaknesses in the available literature, more research is required to establish the risk factors implicated in the transition from acute to chronic TMD pain.

CONCLUSION

This review found some evidence that myofascial pain is associated with the transition risk from acute to chronic TMD pain at a 6-month follow-up and that pain intensity at baseline is associated with more intense TMD pain 6 months later. There is insufficient evidence to draw conclusions about the role of demographics and psychological disorders as independent risk factors.

Painful and non-painful comorbidities associated with short- and long-term painful temporomandibular disorders: A cross-sectional study among adolescents from Brazil, Canada, and France

BACKGROUND

Temporomandibular disorder (TMD) pain is common among adolescents. The association between painful TMD and other comorbidities has been demonstrated. However, the difference between short-term (<6 months) and long-term (≥ 6 months) painful TMD is not yet clear.

OBJECTIVE

The aim of this study was to assess the association between comorbidities and short- and long-term painful TMD among adolescents.

METHODS

In this cross-sectional study, adolescents were recruited from Montreal (Canada), Nice (France), and Arceburgo (Brazil). Self-reported painful TMD, comorbidities, school absence, and analgesic intake were assessed using reliable instruments. Multivariable logistic regression analyses were conducted to assess the study aims.

RESULTS

The prevalence of short- and long-term painful TMD was estimated at 22.29% and 9.93%, respectively. The number of comorbidities was associated with short- (OR = 1.71, 95%CI = 1.53-1.90) and long-term painful TMD (OR = 1.79, 95%CI = 1.55-2.08) compared to controls. Frequent headaches (OR_short-term = 4.39, 95%CI = 3.23-5.98, OR_long-term = 3.69, 95%CI = 2.45-5.57) and back pain (OR_short-term = 1.46, 95%CI=1.06-2.03, OR_long-term  = 1.69, 95%CI = 1.11-2.59) were associated with both painful TMD groups. Frequent neck pain (OR = 2.23, 95%CI = 1.53-3.26) and allergies were only associated with short-term painful TMD (OR = 1.54, 95%CI = 1.13-2.10). Frequent stomach pain was related to long-term (OR = 2.01, 95%CI = 1.35-3.26), and it was the only comorbidity significantly more frequent among the long than short-term TMD (OR = 1.82, 95%CI: 1.14-2.90). These analyses were adjusted by sex, age, and city.

CONCLUSION

In this multi-center study, both short- and long-term painful TMD are associated with frequent headaches and back pain, whereas frequent neck pain and allergies are related to only short-term, and frequent stomach pain with long-term painful TMD.

Prognostic factor analysis in patients with temporomandibular disorders after reversible treatment: study protocol for a prospective cohort study in China

INTRODUCTION

Temporomandibular disorders (TMDs) are complex multifactorial disorders. Reversible treatment has been suggested for the initial management of TMD; however, comparable therapeutic effects of different reversible intervention modalities remain controversial. Various biopsychosocial factors, which may be putative prognostic factors that influence the response to reversible treatment for TMD, have been reported to increase the risk of developing first-onset TMD. However, there is a paucity of research that aims to identify prognostic factors associated with the clinical outcomes of reversible treatment in people with TMD. The objective of this prospective cohort study is to identify prognostic factors that are associated with clinical outcomes of reversible treatment in patients with TMD and to analyse the risk factors that influence the development of chronic TMD.

METHODS AND ANALYSIS

We plan to recruit 834 patients with TMD who meet the inclusion criteria. Once informed consent is obtained, baseline data, including anamnestic data, physical assessments and self-report questionnaires, will be collected from participants at their first clinic visit; subsequently, they will receive 1-4 weeks of reversible treatment. The primary treatment outcome measures will be a change in the anterior maximum mouth opening, worsening of TMD pain scores assessed using a visual analogue scale (VAS) and a reduction in characteristic pain intensity. A good outcome will be defined as an anterior maximal opening ≥35 mm and at least a 30% reduction in VAS scores 3 months after baseline. The association between candidate prognostic factors and clinical outcomes of reversible TMD treatment will be analysed.

ETHICS AND DISSEMINATION

The protocol has been approved by the Ethics Committee of Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China, based on the guidelines outlined in the Declaration of Helsinki (SH9H-2019-T316-4). The results of this study will be reported in accordance with the Strengthening the Reporting of Observational Studies in Epidemiology statement. The authors intend to publish the results in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

ChiCTR2000033328.

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.

Mapping research trends of temporomandibular disorders from 2010 to 2019: A bibliometric analysis

BACKGROUND

Because of various clinical manifestations and complicated courses, temporomandibular disorders (TMDs) are difficult to treat. Current knowledge about this disease remains insufficient for precise treatment after diagnosis.

OBJECTIVES

The objective of this study is to obtain and map the overall literature trends and most cited keywords in TMDs research.

METHODS

Many indicators, including annual number of publications, country distribution, global cooperations, author contributions, original journals, cited references and keywords, were calculated and evaluated using VOSviewer v.1.6.13, which visualised many results, from the WoSCC database.

RESULTS

A total of 3121 papers on TMDs research were retrieved from 2010 to 2019. The United States produced the most articles published, but the most productive institution was the University of Sao Paulo (Brazil). Researchers and institutions conducting TMDs research have shown a very widespread and close connection. TMDs have been studied worldwide by many research centres. Professor Svensson P was the most published researcher in TMDs research and the Journal of Oral Rehabilitation published the most TMDs research articles. The top cited references mainly presented diagnostic criteria of TMDs. The most cited keywords formed clusters: (a) Anatomical factor of TMDs, (b) Symptoms of TMDs and (c) RDC/TMD, the risk factors, biopsychosocial factors and epidemiology of TMDs.

CONCLUSIONS

The research results provide very valuable data for a thorough understanding of the research status of TMDs and demonstrated international cooperation.

The relation of cephalometric features to internal derangements of the temporomandibular joint: A systematic review and meta-analysis of observational studies

PURPOSE

To review and summarize the data on the relationship between craniofacial morphology features and internal derangement (ID) of the temporomandibular joint (TMJ).

METHOD

A systematic review was designed and registered at PROSPERO, CRD42019132731. The PubMed, Embase and Scopus databases were searched for cephalometric studies comparing craniofacial morphology between female patients with TMJ ID and controls. The Newcastle-Ottawa Scale (NOS) was used for quality assessment. Weighted mean differences for cephalometric measurements were pooled for subsequent meta-analysis.

RESULT

From the establishment date to August 2020, 14 of 1038 collected records were selected, which consisted of 772 patients with TMJ ID and 423 controls. These records were eventually pooled for the designed statistical analysis after the NOS quality assessment. Compared with the controls, TMJ ID patients had obviously smaller, retruded and clockwise-rotated mandible, showing significantly decreased S-Na, S-Go, Go-Me, Ar-Pog, Ar-Go, SNB, Na perp Pog, and increased FH-MP, SN-MP, PP-MP, SN to Ar-Go, S-Ar-Go and ANB.

CONCLUSION

Certain craniofacial morphology features were found strongly associated with the presence of TMJ ID, especially the size and position of the mandible.

Insights for temporomandibular disorders management: From psychosocial factors to genetics-A case report

AIMS

This case report aimed to discuss the multifactorial etiology and also the management of temporomandibular disorders (TMD) by addressing important associated psychosocial and biological factors, emphasizing the interaction between these factors and a probable genetic predisposition.

METHODS AND RESULTS

A 21-year-old female patient was evaluated according to Research Diagnostic Criteria for TMD and diagnosed with arthralgia, myofascial pain, disc displacement without reduction, and temporomandibular joint (TMJ) degenerative disease. TMJ alterations were confirmed through magnetic resonance imaging and cone-beam computed tomography. Pressure pain threshold of masticatory structures was evaluated using a pressure algometer. Sleep bruxism, poor sleep quality, migraine with aura, mild anxiety, and history of facial trauma were also identified through anamnesis and clinical examination. Following this, genetic analysis was performed to evaluate the presence of single nucleotide polymorphisms (SNPs) already associated with TMD: SNP COMT Val¹⁵⁸ Met (rs4680), MMP1-1607 (rs1799750), and tumor necrosis factor alpha-308 (rs1800629), which were all present. A personalized treatment for TMD management was performed, and it included self-management programs, occlusal appliance therapy, pharmacotherapy, anxiety management, and stress control. An 8-year follow-up demonstrated long-term stabilization of TMJ degenerative disease.

CONCLUSION

Genetic evaluation, added to anamnesis and clinical examination, could be useful for TMD prognosis and management.

Identification of Biomechanical Properties of Temporomandibular Discs

Material

Experimental and model tests were conducted on ten fresh porcine temporomandibular joint discs. The average thickness of disc tissue was, accordingly, 2.77 mm for the anterior zone, 3.98 mm for the posterior, and 1.54 mm for the intermediate. The selection of research material in the form of porcine discs was due to the similarity to human discs.

Methods

Discs were loaded in cycles, a temporary course with the amplitude 3 N and frequency 0.07 Hz, and growth in the load was 1 N/s. The selection of load frequency was due to real conditions of temporomandibular joint functioning during mastication. The necessary experimental research was conducted on a testing machine with a measurement range of 2.5 kN.

Results

The obtained numeric calculation results indicate that the number of load cycles has a decisive impact on the limitation of energy dispersion capacity through disc tissue. This phenomenon was observed in all the studies on the disc areas. Along with the growth in load cycles, discs are stiffened, and the most significant stiffness was observed in the intermediate area.

Conclusions

Based on the conducted research, it should be concluded that excessive load affecting temporomandibular joints caused by the act of mastication and occlusal forces generated during parafunction and in people with defined long-term bruxism has crucial importance on biomechanical disc properties and hence the course of temporomandibular joint conditions.

Prevalence of clinical signs and pain symptoms of temporomandibular disorders and associated factors in adult Finns

Objective: To assess the prevalence of clinical signs and pain symptoms of temporomandibular disorders (TMD) and associated factors in the Finnish adult population, as well as the association between self-reported TMD pain symptoms and clinical signs.Material and methods: The sample consisted of 1577 Finnish adults who participated in the Health 2011 Survey (BRIF8901). Signs of TMD were assessed using clinical examination, and TMD pain symptoms were inquired using validated questions.Results: Of the study subjects, 35% showed at least one sign of TMD, 8% reported weekly facial pain and 6% weekly pain when biting or jaw opening. According to logistic regression, female gender, poor general health and low level of education increased the risk for most TMD signs and TMD pain symptoms. Muscle or TMJ pain on palpation associated significantly with self-reported weekly facial pain or pain when biting or jaw opening.Conclusion: Over a third of the population showed clinical signs of TMD and less than one-tenth reported TMD pain symptoms. An assessment of a patient's general health needs to be a part of TMD diagnosis and treatment. The Finnish versions of the validated questions are applicable for screening of TMD pain.

Model for Predicting Temporomandibular Dysfunction: Use of Classification Tree Analysis

The aim of this study was to construct a predictive model that uses classification tree statistical analysis to predict the occurrence of temporomandibular disorder, by dividing the sample into groups of high and low risk for the development of the disease. The use of predictive statistical approaches that facilitate the process of recognizing and/or predicting the occurrence of temporomandibular disorder is of interest to the scientific community, for the purpose of providing patients with more adequate solutions in each case. This was a cross-sectional analytical population-based study that involved a sample of 776 individuals who had sought medical or dental attendance at the Family Health Units in Recife, PE, Brazil. The sample was submitted to anamnesis using the instrument Research Diagnostic Criteria for Temporomandibular Disorders. The data were inserted into the software Statistical Package for the Social Sciences 20.0 and analyzed by the Pearson Chi-square test for bivariate analysis, and by the classification tree method for the multivariate analysis. Temporomandibular disorder could be predicted by orofacial pain, age and depression. The high-risk group was composed of individuals with orofacial pain, those between the ages of 25 and 59 years and those who presented depression. The low risk group was composed of individuals without orofacial pain. The authors were able to conclude that the best predictor for temporomandibular disorder was orofacial pain, and that the predictive model proposed by the classification tree could be applied as a tool for simplifying decision making relative to the occurrence of temporomandibular disorder.

Peripheral mechanisms contribute to comorbid visceral hypersensitivity induced by preexisting orofacial pain and stress in female rats

BACKGROUND

Stress exacerbates many chronic pain syndromes including irritable bowel syndrome (IBS). Among these patient populations, many suffer from comorbid or chronic overlapping pain conditions and are predominantly female. Nevertheless, basic studies investigating chronic psychological stress-induced changes in pain sensitivity have been mostly carried out in male rodents. Our laboratory developed a model of comorbid pain hypersensitivity (CPH) (stress in the presence of preexisting orofacial pain inducing chronic visceral pain hypersensitivity that significantly outlasts transient stress-induced pain hypersensitivity (SIH)) facilitating the study of pain associated with IBS. Since CPH and SIH are phenotypically similar until SIH resolves and CPH persists, it is unclear if underlying mechanisms are similar.

METHODS

In the present study, the visceromotor response (VMR) to colorectal distention was recorded in the SIH and CPH models in intact females and ovariectomized rats plus estradiol replacement (OVx + E2). Over several months, rats were determined to be susceptible or resilient to stress and the role of peripheral corticotrophin-releasing factor (CRF) underlying in the pain hypersensitivity was examined.

KEY RESULTS

Stress alone induced transient (3-4 weeks) visceral hypersensitivity, though some rats were resilient. Comorbid conditions increased susceptibility to stress prolonging hypersensitivity beyond 13 weeks. Both models had robust peripheral components; hypersensitivity was attenuated by the CRF receptor antagonist astressin and the mast cell stabilizer disodium cromoglycate (DSCG). However, DSCG was less effective in the CPH model compared to the SIH model.

CONCLUSIONS AND INFERENCES

The data indicate many similarities but some differences in mechanisms contributing to comorbid pain conditions compared to transient stress-induced pain.

Incident injury is strongly associated with subsequent incident temporomandibular disorder: results from the OPPERA study

Cross-sectional studies confirm, as expected, a positive association between jaw injury and painful temporomandibular disorders (TMDs), but prospective evaluations are lacking. We prospectively assessed incident jaw injury, injury type, and development of TMD in adults aged 18 to 44 years. Data were collected from 3258 individuals from communities surrounding 4 US academic institutes between 2006 and 2008. At enrollment, participants reported no TMD history and no facial injuries in the previous 6 months. Quarterly, follow-up questionnaires assessed incident jaw injury, which was classified as intrinsic (attributed to yawning or prolonged mouth opening) or extrinsic (attributed to other causes). Examiners classified incident TMD during a median follow-up period of 2.8 years (range 0.2-5.2 years). Cox regression models used jaw injury as a time-dependent covariate to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association with incident TMD. Among 1729 participants with complete data, 175 developed TMD. Eighty percent of injuries were intrinsic. Temporomandibular disorder annual incidence was nearly twice as high in those experiencing jaw injury (5.37%) compared with those who did not (3.44%). In the Cox model that accounted for timing of injury, the corresponding HR was 3.94 (95% CI = 2.82-5.50) after adjusting for study site, age, race, and sex. Hazard ratios did not differ (P = 0.91) for extrinsic injuries (HR = 4.03, 95% CI = 2.00-8.12) and intrinsic injuries (HR = 3.85, 95% CI = 2.70-5.49). Jaw injury was strongly associated with incident TMD. If surveillance and intervention after jaw injury is to be effective in preventing TMD, they should focus on both intrinsic and extrinsic injuries.

Standard Correction of Vision Worsens EMG Activity of Pericranial Muscles in Chronic TMD Subjects

Recent studies showed an evident correlation between the stomatognathic system and the visual system. These results suggest that subjects who are affected by both temporomandibular (TMD) disorders and refractive disorders present with altered control of pericranial musculature tone and higher open-eye electromyographic (EMG) values. The objective of this work was to evaluate the effects of standard vision correction on EMG in subjects suffering from TMD compared with application of the same vision treatments to non-TMD subjects. 40 subjects were enrolled in this study. The test group included 20 myopic subjects and also included patients with TMD. The control group included 20 healthy myopic subjects. All of the participants underwent a complete ocular examination and a sEMG analysis. The results showed that TMD subjects with vision disorders that are corrected with standard glasses present EMG values that are significantly higher than those presented by non-TMD subjects with vision disorders and standard glasses. Infact, in TMD subjects, eye correction did not have a positive effect on the stomatognathic or pericranial musculature.

The prevalence of first-onset temporomandibular disorder in low back pain and associated risk factors: A nationwide population-based cohort study with a 15-year follow-up

The coexistence of low back pain (LBP) and temporomandibular disorder (TMD) has often been noted clinically. However, studies of the association between these two conditions involving a large population with longitudinal evidences are lacking. Therefore, the study aimed to investigate the association between LBP and TMD in a nationwide-matched cohort population with a 15-year follow-up.Data of 65,121 patients newly diagnosed with LBP were analyzed, along with those of 195,363 (1:3) sex- and age-matched controls. Multivariate Cox regression analysis was used to determine TMD risk between the LBP and non-LBP groups. Kaplan-Meier method was used for determining the cumulative risk of first-onset TMD between groups, with a 15-year follow-up.The LBP group was more likely to develop first-onset TMD (adjusted hazards ratio (HR) = 1.561, P < .001), after adjusting for demographic variables and comorbidities. The risk factors for TMD were LBP, young age, higher insured premium, and osteoporosis. In the subgroup analysis, the LBP group had a higher risk of TMD than the non-LBP group in all stratifications.LBP is the risk factor contributing to the development of first-onset TMD. Therefore, clinicians should be reminded to manage LBP disorders concurrently when treating TMD.

Associations of Sleep Disturbance, Atopy, and Other Health Measures with Chronic Overlapping Pain Conditions

AIMS

To quantify the contributions of atopic disorders, sleep disturbance, and other health conditions to five common pain conditions.

METHODS

This cross-sectional analysis used data from 655 participants in the OPPERA study. The authors investigated the individual and collective associations of five chronic overlapping pain conditions (COPCs) with medically diagnosed atopic disorders and self-reported sleep disturbance, fatigue, and symptoms of obstructive sleep apnea. Atopic disorders were allergies, allergic rhinitis, atopic dermatitis, allergic asthma, urticaria, allergic conjunctivitis, and food allergy. Logistic regression models estimated odds ratios as measures of association with temporomandibular disorders, headache, irritable bowel syndrome, low back pain, and fibromyalgia. Measures of sleep and atopy disorders were standardized to z scores to determine the relative strength of their associations with each COPC. Sociodemographic characteristics and body mass index were covariates. Random forest regression analyzed all variables simultaneously, computing importance metrics to determine which variables best differentiated pain cases from controls.

RESULTS

Fatigue and sleep disturbance were strongly associated with each COPC and with the total number of COPCs. An increase of one standard deviation in fatigue or sleep disturbance score was associated with approximately two-fold greater odds of having a COPC. In random forest models, atopic disorders contributed more than other health measures to differentiating between cases and controls of headache, whereas other COPCs were best differentiated by measures of fatigue or sleep.

CONCLUSION

Atopic disorders, previously recognized as predictors of poor sleep, are associated with COPCs after accounting for sleep problems.

Premorbid and concurrent predictors of TMD onset and persistence

BACKGROUND

Multiple risk factors predict temporomandibular disorders (TMD) onset, but temporal changes in risk factors and their contribution to risk of TMD have not been evaluated. The study aims were to (a) describe changes occurring in premorbid TMD risk factors when re-measured at TMD onset and 6 months later, and (b) determine if measures of change improve accuracy in predicting TMD incidence compared to premorbid measures alone.

METHODS

In this observational prospective cohort study at four university research clinics, 3,258 community-based, 18- to 44-year-olds without TMD were enrolled. During the 3-year median follow-up, 260 incident cases of first-onset TMD were identified, and 196 TMD-free subjects were selected as matched controls. Six-months later, 147 of 260 incident cases (56.6%) were re-examined revealing 72 (49%) with 'persistent TMD' and 75 (51%) whose condition had resolved ('transient TMD'). Virtually all (126) of the 127 re-examined controls remained without TMD. Questionnaires and clinical measurements evaluated risk factors from clinical, health, psychological and behavioural and neurosensory domains.

RESULTS

Most risk factors across all four domains increased with TMD onset, remained elevated in the persistent group and declined in the transient group (i.e., significant ANOVA interactions, p < .05). Accuracy in predicting first-onset TMD, quantified as area under the receiver operating characteristic curve was 0.71 (95% CL 0.68, 0.73) using only premorbid measures of risk factors, which increased to 0.91 (95% CL 0.89, 0.94) after addition of change measures.

CONCLUSIONS

TMD pain onset and persistence appear to be determined by enduring characteristics of the person as well as mutually interactive with temporally evolving variables.

SIGNIFICANCE

TMD is known to be a complex disorder, in which onset and persistence are associated with disease-related variables in multiple domains, including environmental exposure, clinical, psychological, health status, and pain processing variables. Using a more dynamic approach in order to capture change across time, many aspects of those domains were found to worsen prior to the reporting of pain, with bidirectional influences between domains and pain emergence likely. TMD onset appears to represent the cumulative effect of multiple system dysregulation.

Low Back Pain and Associated Factors among Primary School Teachers in Mekele City, North Ethiopia: A Cross-Sectional Study

BACKGROUND

Low back pain (LBP) is the most prevalent musculoskeletal disorder among teachers. The pain, which is widely considered to be caused by occupational activities, has a significant impact on teachers' quality of life because it results in frequent sick leaves, functional impairment, and early retirement. It is also demanding in terms of treatment costs, individual suffering, and discontinuation of jobs. Therefore, this study assessed the magnitude of low back pain and associated factors among primary school teachers in Mekele City, north Ethiopia.

METHODS

An institution-based cross-sectional study which included 611 public primary school teachers of Mekele City was conducted from March to April 2015. A multivariable logistic regression analysis was used to identify factors associated with low back pain. The adjusted odds ratio (AOR) with a 95% confidence interval (CI) was used to show the strength of the associations, and variables with a p value of less than 0.05 were considered statistically significant.

RESULTS

In this study, the prevalence of low back pain was 74.8% (95% CI: 71.4-78.2). According to the multivariate analysis, the pain was associated with teachers' sleeping disturbance (AOR = 6.99; 95% CI: 2.20, 13.63), prolonged standing (AOR = 4.78; 95% CI: 3.75, 9.32), and irregular physical exercise (AOR = 1.46; 95% CI: 1.29, 5.10).

CONCLUSION

The study showed that the prevalence of low back pain was high. Sleeping disturbance, prolonged standing during sessions, and irregular physical activity were significantly associated with the problem. Therefore, addressing work-related and individual factors is essential for decreasing the burden.

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.

Temporomandibular disorder and headache in university professors

[Purpose] Temporomandibular disorder is a condition with a multifactor etiology that involves the temporomandibular joint, bones, surrounding muscles and facial pain is the most common symptom. This study evaluated the possible association between headache and temporomandibular disorder in university professors. [Participants and Methods] Twenty-seven professors were recruited and answered the Axis II of the Research Diagnostic Criteria for Temporomandibular Disorders for the evaluation and diagnosis of temporomandibular disorder and filled out a “Headache Diary” proposed by the American Headache Society. [Results] The university professors showed headache and temporomandibular disorder, but no association was found between the two conditions. Comparing the gender, the males were most frequently affected, but females had more intensity of signs and symptoms. There is a lack of data on the population addressed in the present study. [Conclusion] Indeed, this was the first such study developed with university professors. It is of considerable importance to develop further studies to investigate the possible association between headache and temporomandibular disorder.

Long-term changes in biopsychosocial characteristics related to temporomandibular disorder: findings from the OPPERA study

Painful temporomandibular disorders (TMDs) are both consequence and cause of change in multiple clinical, psychosocial, and biological factors. Although longitudinal studies have identified antecedent biopsychosocial factors that increase risk of the TMD onset and persistence, little is known about long-term change in those factors after TMD develops or remits. During a 7.6-year median follow-up period, we measured change in psychosocial characteristics, pain sensitivity, cardiovascular indicators of autonomic function, and clinical jaw function among 189 participants whose baseline chronic TMD status either persisted or remitted and 505 initially TMD-free participants, 83 of whom developed TMD. Among initially TMD-free participants who developed TMD, symptoms and pain sensitivity increased, whereas psychological function worsened. By contrast, participants with chronic TMD at baseline tended to show improved TMD symptoms, improved jaw function, reduced somatic symptoms, and increased positive affect. In general, clinical and psychosocial variables more frequently changed in parallel with TMD status compared with pain sensitivity and autonomic measures. These findings demonstrate a complex pattern of considerable changes in biopsychosocial function associated with changes in TMD status. In particular, several biopsychosocial parameters improved among participants with chronic TMD despite pain persisting for years, suggesting considerable potential for ongoing coping and adaptation in response to persistent pain.

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

Objective: We studied whether primary care temporomandibular disorder (TMD) patients reporting different levels of pain-related disability differ in terms of comorbid pains, general health conditions and quality of life.Material and methods: Consecutive TMD pain patients (n = 399) seeking treatment in primary care completed a questionnaire on comorbid pains and their interference and the Finnish version of the RAND-36-item quality of life questionnaire. Medical diagnoses confirmed by doctors were recorded. The patients were classified according to the Graded Chronic Pain Scale (GCPS) of the Research Diagnostic Criteria for TMD (RDC/TMD). The patients were classified: no disability group (0 disability points), low disability group (1-2 disability points) and high disability group (3-6 disability points).Results: Compared to patients in the no-disability group, patients in the high- and low-disability groups reported more comorbid pain conditions (p < .001), and experienced these as more intense and interfering more with daily life (p < .05). Patients in the high-disability group reported more general health-related medical diagnoses than patients in the no-disability group (p < .05). Furthermore, patients with low or high pain-related disability indicated poorer quality of life in all RAND-36 subscales than those with no disability (p < .05).Conclusions: The findings suggest that GCPS-related disability scoring can be used as a simple screening instrument to identify TMD patients with different degrees of health burdens.

A questionnaire-based study of sleep-wake patterns and sleep quality in a TMJ and orofacial pain clinic

OBJECTIVE

To determine the relationships among sleep quality, perceived pain, and psychological distress among patients with TMJ and orofacial pain.

METHODS

The authors examined 3276 patients with temporomandibular disorder (TMD) who visited the Orofacial Pain Clinic at Yonsei University College of Dentistry. The authors conducted a survey using the sleep-quality questionnaire and classified TMD patients into two groups based on Diagnostic Criteria for TMD. For statistical analysis, the authors calculated the correlations between pain intensity as measured using a numeric rating scale (NRS) and various factors.

RESULTS

The statistical analysis revealed correlations between pain intensity on the NRS and some of the factors in the sleep questionnaire. The pain intensity increased with age and for lower sleep efficiency (both p < 0.05).

CONCLUSION

These results imply that clinicians treating patients with orofacial pain should examine their sleep-wake patterns and sleep quality.