The Evolution of TMD Diagnosis: Past, Present, Future

Dietary supplementation with grape seed extract from Vitus vinifera prevents suppression of GABAergic protein expression in female Sprague Dawley trigeminal ganglion in a model of chronic temporomandibular joint disorder

OBJECTIVE

To investigate cellular changes in protein expression in the trigeminal ganglion in an established preclinical chronic model of temporomandibular joint disorder (TMD) in response to grape seed extract (GSE) supplementation based on its beneficial use in preclinical chronic orofacial pain models.

DESIGN

Three experimental conditions included female Sprague-Dawley rats as naïve controls, and animals subjected to neck muscle inflammation and prolonged jaw opening with and without daily supplementation of GSE in the drinking water prior to inflammation. Changes were evaluated in mechanical sensitivity to von Frey filaments and protein expression in the trigeminal ganglion of animals 14 days post jaw opening.

RESULTS

Calcitonin-gene related peptide and protein kinase A, proteins positively associated with peripheral sensitization and enhanced nociception, did not show elevated expression at day 14 in the model compared to naïve or GSE supplemented animals. However, neuronal levels of glutamate decarboxylase (GAD) 65/67, which are enzymes responsible for the synthesis of the inhibitory neurotransmitter GABA that functions to suppress neuronal excitability, were significantly decreased on day 14 post jaw opening. Similarly, a significant decrease in neuronal expression of the GABA receptor subunits GABAB1 and GABAB2, but not GABAA, was observed in the TMD model. Importantly, GSE prevented suppression of GAD 65/67 and GABAB subunits, maintaining levels similar to naïve animals.

CONCLUSION

Results from our study provide evidence of the downregulation of inhibitory GABAergic proteins in trigeminal ganglion neurons in a preclinical chronic TMD model and the benefits of GSE supplementation in preventing their suppression and maintaining normal levels.

Deep learning for temporomandibular joint arthropathies: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

The accurate diagnosis of temporomandibular disorders continues to be a challenge, despite the existence of internationally agreed-upon diagnostic criteria. The purpose of this study is to review applications of deep learning models in the diagnosis of temporomandibular joint arthropathies.

MATERIALS AND METHODS

An electronic search was conducted on PubMed, Scopus, Embase, Google Scholar, IEEE, arXiv, and medRxiv up to June 2023. Studies that reported the efficacy (outcome) of prediction, object detection or classification of TMJ arthropathies by deep learning models (intervention) of human joint-based or arthrogenous TMDs (population) in comparison to reference standard (comparison) were included. To evaluate the risk of bias, included studies were critically analysed using the quality assessment of diagnostic accuracy studies (QUADAS-2). Diagnostic odds ratios (DOR) were calculated. Forrest plot and funnel plot were created using STATA 17 and MetaDiSc.

RESULTS

Full text review was performed on 46 out of the 1056 identified studies and 21 studies met the eligibility criteria and were included in the systematic review. Four studies were graded as having a low risk of bias for all domains of QUADAS-2. The accuracy of all included studies ranged from 74% to 100%. Sensitivity ranged from 54% to 100%, specificity: 85%-100%, Dice coefficient: 85%-98%, and AUC: 77%-99%. The datasets were then pooled based on the sensitivity, specificity, and dataset size of seven studies that qualified for meta-analysis. The pooled sensitivity was 95% (85%-99%), specificity: 92% (86%-96%), and AUC: 97% (96%-98%). DORs were 232 (74-729). According to Deek's funnel plot and statistical evaluation (p =.49), publication bias was not present.

CONCLUSION

Deep learning models can detect TMJ arthropathies high sensitivity and specificity. Clinicians, and especially those not specialized in orofacial pain, may benefit from this methodology for assessing TMD as it facilitates a rigorous and evidence-based framework, objective measurements, and advanced analysis techniques, ultimately enhancing diagnostic accuracy.

How do the mindfulness and sensory-behavioural-emotional aspects influence the painful experience related to temporomandibular disorder?

BACKGROUND

Chronic pain is persistent or recurrent pain lasting longer than 3 months. The experience of temporomandibular disorder (TMD)-related pain is modulated by emotional and social factors, with mindfulness encapsulating these aspects.

OBJECTIVE

To investigate the association between cognitive-behavioural-emotional characteristics, mindfulness and the painful experience in women with chronic pain-related TMD.

METHODS

A cross-sectional study was conducted, including 90 women aged between 18 and 61 years old, diagnosed with chronic pain-related TMD according to the Diagnostic Criteria for Temporomandibular Disorder, considering both temporomandibular joint and muscle pain. Specific instruments were employed to assess cognitive-behavioural-emotional aspects. The Mindful Attention Awareness Scale and the Five Facets of Mindfulness Questionnaire scales evaluated the level and construct of mindfulness. The relationship between variables was analysed using bivariate association tests (.05 > p < .20), followed by multiple regression tests (p < .05).

RESULTS

The heightened experience of pain correlated with increasing age, a low level of education, the attribution of the locus of control by chance, and lower levels of mindfulness (p < .05). The heightened experience of pain was negatively influenced by mindfulness levels (p < .05). On the other hand, the painful experience was mainly influenced by facets describing negative formulation, distraction, non-reactivity and non-judgement (p < .05).

CONCLUSION

Demographic, cognitive-behavioural-emotional data and levels of mindfulness and its facets presented different influence weights on the painful experience. These findings provide support for future studies focusing on mindfulness strategies, education and pain management in women with chronic pain-related TMD.

Association between clinical symptoms and MRI image findings in symptomatic temporomandibular joint (TMJ) disease: A systematic review

To evaluate the association between clinical signs and symptoms of temporomandibular joint (TMJ) and magnetic resonance image (MRI) findings in patients with temporomandibular disorders (TMD). Relevant articles on humans over 18 years of age were obtained from five databases (Ovid MEDLINE, PubMed, Scopus, Web of Science, and Google Scholar) up to August 2022. Risk of bias assessment was completed using the Joanna Briggs Institute critical appraisal tools. The GRADEpro (Grading of Recommendations, Assessment, Development, and Evaluation) instrument was applied to assess the level of evidence across studies in a GRADE Summary of Findings table. In total, 22 studies were included in this systematic review. Of these, 11 studies highlighted that joint pain was positively associated with particular MRI findings: joint effusion, bone marrow edema, disk displacement with/without reduction, and condylar erosion. Masticatory muscle pain was found to have a strong positive correlation with disk displacement in four studies. Five studies found no significant association between MRI findings and masticatory muscle pain. Range of motion and MRI findings were examined in six studies. Limited mouth opening was found to be correlated with disk displacement in five studies. Of the 11 studies evaluating the correlation between joint noise and MRI findings, eight reported a significant association between disk displacement and TMJ noise. The results suggested that patients with joint pain and limited range of motion may benefit from MRI. Patients exhibiting primarily muscle pain are unlikely to benefit clinically from MRI. Future studies with improved quality are warranted.

Exploring the causal effects of sleep characteristics on TMD-related pain: a two-sample Mendelian randomization study

OBJECTIVES

The study was to explore the causal effects of sleep characteristics on temporomandibular disorder (TMD)-related pain using Mendelian randomization (MR) analysis.

MATERIALS AND METHODS

Five sleep characteristics (short sleep, insomnia, chronotype, snoring, sleep apnea) were designated as exposure factors. Data were obtained from previous publicized genome-wide association studies and single nucleotide polymorphisms (SNPs) strongly associated with them were utilized as instrumental variables (IVs). TMD-related pain was designed as outcome variable and sourced from the FinnGens database. MR analysis was employed to explore the causal effects of the five sleep characteristics on TMD-related pain. The causal effect was analyzed using the inverse variance-weighted (IVW), weighted median, and MR-Egger methods. Subsequently, sensitivity analyses were conducted using Cochran's Q tests, funnel plots, leave-one-out analyses, and MR-Egger intercept tests.

RESULTS

A causal effect of short sleep on TMD-related pain was revealed by IVW (OR: 1.60, 95% CI: 1.06-2.41, P = 0.026). No causal relationship was identified between other sleep characteristics (insomnia, chronotype, snoring, sleep apnea) and TMD-related pain.

CONCLUSIONS

Our study suggests that short sleep may increase the risk of TMD-related pain, while there was no causal relationship between other sleep characteristics and TMD-related pain. Further studies are warranted to deepen and definitively clarify their relationship.

CLINICAL RELEVANCE

These findings reveal that the short sleep may be a risk factor of TMD-related pain and highlight the potential therapeutical effect of extending sleep time on alleviating TMD-related pain.

Prevalence and associated factors of health anxiety in patients with temporomandibular disorders

OBJECTIVES

To investigate the prevalence and associated factors of health anxiety (HA) in patients with Temporomandibular Disorders (TMDs) using the 8-item Whiteley Index (WI-8) scale.

MATERIALS AND METHODS

Three hundred and twenty-nine TMDs patients completed the Visual Analog Scale (VAS), WI-8, Jaw Functional Limitation Scale-8 (JFLS-8), Patient Health Questionnaire-9 (PHQ-9), and Generalized Anxiety Disorder-7 (GAD-7) scales. Clinical examinations were conducted following the Diagnostic Criteria for TMDs Axis I.

RESULTS

The prevalence of HA among TMDs patients was 18.54%. Patients with HA had higher scores of VAS-current (p = 0.026), VAS-maximum (p = 0.024), VAS-average (p = 0.030), JFLS-8 (p < 0.001), GAD-7 (p < 0.001) and PHQ-9 (p < 0.001), lower maximum mouth opening (p = 0.016), lower proportion of structure-related TMDs (p = 0.028), and higher proportion of pain-related TMDs (p < 0.001) compared to those without HA. The correlation coefficient was 0.61 (p < 0.001) between WI-8 and GAD-7 and 0.64 (p < 0.001) between WI-8 and PHQ-9.

CONCLUSION

Approximately one-fifth of patients with TMDs experienced HA. HA was associated with pain perception, functional limitations, depressive, and anxiety symptoms in individuals with TMDs. HA may contribute to heightened subjective pain experiences rather than structural changes in the TMJ.

Analysis of the Effect of Exams on Perceived Stress and Temporomandibular Joint Status in Physiotherapy Students: A Pilot Study

Background and Objectives: Temporomandibular disorders or dysfunction (TMDs) encompass a range of complex conditions that impact the temporomandibular joint (TMJ), chewing muscles, teeth, and/or their supporting tissues. Stress is one of the most associated factors studied as a TMD predictor. The aim is to figure out the influence of stress on TMJ status and salivary cortisol in university students during and before exams. Materials and Methods: The study was non-experimental, employing a longitudinal, analytical, observational cohort design. The study population consisted of students enrolled in the physiotherapy degree program at the Alfonso X El Sabio University (Madrid, Spain). Data were collected during two distinct academic periods: the first period was characterized by low academic stress and no exams, and the second period coincided with the high academic stress of final course exams. The collected results included sociodemographic data, assessment of TMJ status (Fonseca Index), evaluation of muscle evaluation (masseter, upper trapezius, and sternocleidomastoid) using a MOXY Monitor (muscle oxygenation) and Neurotrac® (surface EMG, sEMG), assessment of perceived stress (PSS-14), and measurement of salivary cortisol (enzyme immunoassay with Elisa). The statistical analysis was conducted with a confidence level of 95% (p ≤ 0.05) and asymptotic or bilateral significance. Results: 70 students were analyzed during two different measurement periods. According to the Fonseca Index, initially, 37.14% of the analyzed students showed mild TMDs, 17.14% moderate TMDs, and 45.72% showed no TMDs. In general terms, stress increased with age and is related to female sex, maximum mouth opening decreased with age, oxygen saturation decreased with age and academic stress, and myoglobin concentration was related to age. Furthermore, muscle contraction decreased during higher academic stress and increased with age. For women, age was a risk factor for suffering from TMDs, and stress worsened the transition from having TMDs to having no TMDs in both sexes. Conclusions: Academic stress influences TMJ status and muscle outcomes such as oxygen saturation, myoglobin concentration, and muscle contraction, although more research is needed.

Comparison of Machine Learning Algorithms Fed with Mobility-Related and Baropodometric Measurements to Identify Temporomandibular Disorders

Temporomandibular disorders (TMDs) refer to a group of conditions that affect the temporomandibular joint, causing pain and dysfunction in the jaw joint and related muscles. The diagnosis of TMDs typically involves clinical assessment through operator-based physical examination, a self-reported questionnaire and imaging studies. To objectivize the measurement of TMD, this study aims at investigating the feasibility of using machine-learning algorithms fed with data gathered from low-cost and portable instruments to identify the presence of TMD in adult subjects. Through this aim, the experimental protocol involved fifty participants, equally distributed between TMD and healthy subjects, acting as a control group. The diagnosis of TMD was performed by a skilled operator through the typical clinical scale. Participants underwent a baropodometric analysis by using a pressure matrix and the evaluation of the cervical mobility through inertial sensors. Nine machine-learning algorithms belonging to support vector machine, k-nearest neighbours and decision tree algorithms were compared. The k-nearest neighbours algorithm based on cosine distance was found to be the best performing, achieving performances of 0.94, 0.94 and 0.08 for the accuracy, F1-score and G-index, respectively. These findings open the possibility of using such methodology to support the diagnosis of TMDs in clinical environments.

Temporomandibular disorders: the most common diagnostic approaches

BACKGROUND

Temporomandibular disorders (TMDs) are a heterogeneous group of conditions involving the temporomandibular joint complex, and surrounding musculature and osseous components. They are a multifactorial disease that can be determined by organic, genetic aspects, oral parafunctional habits, and psychological stress. They have an annual incidence of more than 5% of the population and about 6% to 12% of the population is affected by symptoms. The diagnostic criteria (DC), introduced by Dworkin, is considered the standard system to diagnose this disease in a specific way. Imaging can support the diagnosis of TMD when history and physical examination findings are equivocal. The aim of the study was to evaluate instrumental examinations and therapies, clinicians prefer to use in different cases of TMDs.

METHODS

An anonymized survey, available in two languages (Italian and English), was given to 450 patients, 398 (120 males, 274 females and 4 who did not answer) of different private dental practices were considered, using Google Form (Google LLC, Mountain View, CA, USA) and used an electronic platform, from September 2021 to February 2022. There was no reminder sent to patients to let them feel free to answer.

RESULTS

We performed binary regression for oral bite prescription considering common symptoms and found that the most representative is jaw block (P=0.007, exponential value [EXP]=0.509), followed by TMJ noises (P=0.01, EXP=0.503) and feeling stressed (P=0.04, EXP=1.125) while headache and tinnitus resulted not significant.

CONCLUSIONS

The study highlighted that magnetic resonance imaging (MRI) is the most instrumental examination adopted by the clinicians and the oral splint(bite) is the therapy most widespread nowadays, even if TMDs are a multifactorial disease that is not, probably, only linked to an alteration of dental occlusion.

Constructing the brief diagnostic criteria for temporomandibular disorders (bDC/TMD) for field testing

BACKGROUND

Despite advances in temporomandibular disorders' (TMDs) diagnosis, the diagnostic process continues to be problematic in non-specialist settings.

OBJECTIVE

To complete a Delphi process to shorten the Diagnostic Criteria for TMD (DC/TMD) to a brief DC/TMD (bDC/TMD) for expedient clinical diagnosis and initial management.

METHODS

An international Delphi panel was created with 23 clinicians representing major specialities, general dentistry and related fields. The process comprised a full day workshop, seven virtual meetings, six rounds of electronic discussion and finally an open consultation at a virtual international symposium.

RESULTS

Within the physical axis (Axis 1), the self-report Symptom Questionnaire of the DC/TMD did not require shortening from 14 items for the bDC/TMD. The compulsory use of the TMD pain screener was removed reducing the total number of Axis 1 items by 18%. The DC/TMD Axis 1 10-section examination protocol (25 movements, up to 12 sets of bilateral palpations) was reduced to four sections in the bDC/TMD protocol involving three movements and three sets of palpations. Axis I then resulted in two groups of diagnoses: painful TMD (inclusive of secondary headache), and common joint-related TMD with functional implications. The psychosocial axis (Axis 2) was shortened to an ultra-brief 11 item assessment.

CONCLUSION

The bDC/TMD represents a substantially reduced and likely expedited method to establish (grouping) diagnoses in TMDs. This may provide greater utility for settings requiring less granular diagnoses for the implementation of initial treatment, for example non-specialist general dental practice.

Impact of professional, recreational and nonsinging on temporomandibular disorders - a comparative study based on a self-assessment questionnaire

BACKGROUND

This study investigates the relationship between professional and recreational singing on temporomandibular disorders (TMDs) in women compared to a nonsinging control group.

METHODS

A total of 288 female subjects between the ages of 18 and 45 participated in the self-assessment questionnaire including demographic data, as well as questions on vocal practice and TMDs symptoms. Depending on the singing time per week, the (non)vocalists were assigned to the groups professional (n = 96), recreational (n = 96) and nonsingers (n = 96).

RESULTS

The TMDs prevalence in professional singers (42%) was higher than that in recreational singers (31%) and noticeably higher than that in nonsingers (25%). The Fisher-Freeman-Halton exact test showed that the differences between the groups were not noticeable (p = .053) but could be formulated as tendencies. The professionals suffered much more from restricted jaw movement (p = .004; OR = 2.718; 95% CI = 1.409-5.242), temporomandibular joint sounds (p < .009; OR = 2.267; 95% CI = 1.264-4.064) and temporomandibular pain (p = .010; OR = 2.333; 95% CI = 1.264-4.308) than nonsingers.

CONCLUSIONS

Singing might have an enhancing effect on the appearance of TMDs. In particular, professional singers suffered more from self-reported TMDs than recreational singers and nonsingers. In addition to the high level of physical workload if participating in professional singing, the psychosocial impact should be investigated more in further studies. No new treatment strategies resulted from this study, as the etiological significance of singing is still unclear. Knowledge about risk factors for multifactorial TMDs can help practitioners and patients prevent and treat TMDs.

Temporomandibular disorder in individuals with spinal cord injuries

OBJECTIVE

This study evaluated Temporomandibular Disorder (TMD) in individuals with Spinal Cord Injuries (SCI) compared to individuals without physical disabilities.

DESIGN

Cross-sectional.

SETTING

International Fair of Technologies in Rehabilitation and Accessibility (REATECH) and School of Dentistry at the University of São Paulo (USP), Brazil.

PARTICIPANTS

In total, 19 patients with SCI and 19 patients without SCI (36.9 ± 11.4 years old) were examined by a calibrated examiner.

METHODS

using the following parameters: cervical spine mobility, palpation of muscle groups of the head and neck, functional manipulation of the lateral and medial pterygoids, and joint palpation (Diagnostic Criteria). The pattern and amplitude of mandibular movements were determined during screening using the Helkimo index.

STATISTICAL ANALYSES

Student's t-test, chi-square, Fisher's exact and Shapiro-Wilk test were used.

RESULTS

The groups did not differ in the presence of noise, pain, temporomandibular joint palpation, locking, dislocation, jaw pain, muscle sensitivity, or in pain, mobility of the cervical spine and functional manipulation. With respect to the jaw mobility index, the groups differed in range of movement (P = 0.020) and maximum right lateral movement (P = 0.007), with the worst values in the SCI group. The groups also differed in relation to lateral flexion in cervical mobility, in which the group without SCI presented better results (P = 0.046).

CONCLUSION

The Spinal Cord Injuries group showed higher levels of TMD in terms of range of movement, lateral flexion, and maximum right lateral movement, than the individuals without physical disabilities, demonstrating a clinical significance between cervical and mandibular disability in this group.

Relationship between masseter muscle activity during wakefulness and temporomandibular disorder-related symptoms

BACKGROUND

Masseter muscle activity during wakefulness may be associated with temporomandibular disorder (TMD)-related symptoms, psychosocial status and pain-related disability; however, this relationship is unclear.

OBJECTIVES

This study aimed to determine the relationship between masseter muscle electromyography (EMG) burst/duration during wakefulness and TMD-related symptoms, psychosocial status and pain-related disability.

METHODS

Sixty participants were assessed masseter muscle activity during wakefulness using a data-logger-type ultraminiature EMG system and TMD-related symptoms, psychosocial status and pain-related disability through Axis I and II of the diagnostic criteria for TMD (DC/TMD). EMG bursts lasting longer than 0.25 s but less than 2.0 s and those lasting longer than 2.0 s were classified as phasic and tonic bursts, respectively.

RESULTS

Participants with palpation-related pain in the temporalis and masseter muscles, as assessed through the DC/TMD examination form in Axis I, had more bursts (number/h) (p = .035 and p = .009, respectively) and longer duration (time/h) (p = .013 and p = .004, respectively) of tonic bursts of the masseter muscle during wakefulness. Participants with palpation-related pain in the masseter muscles had higher oral behaviour scores during wakefulness using Axis II (p = .001), which affected the number and duration of tonic bursts of the masseter muscle activity during wakefulness (p = .011 and p = .007, respectively).

CONCLUSION

As tonic bursts mainly reflect clenching, individuals with pain in the masseter muscles by palpation may have a high frequency and longer duration of clenching, as well as a high frequency of oral behaviours during wakefulness.

Is painful temporomandibular disorder a real headache for many patients?

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

Causal effects of life course adiposity on temporomandibular disorders: A Mendelian randomization study

BACKGROUND

Previous studies investigated the associations between obesity and temporomandibular disorders (TMDs), but the evidence for the causal inferences was unclear.

OBJECTIVE

We aimed to investigate the causal link between life course adiposity and TMDs.

METHODS

Mendelian randomization (MR) studies were performed using genetic instruments for birth weight (BW) (N = 261 932), childhood body mass index (BMI) (N = 39 620), childhood body size (N = 454 718), adult BMI (N = 99 998), body fat percentage (N = 454 633) and TMDs (N = 211 023). We assessed the overall effect of each life course adiposity factor via inverse-variance weighted (IVW), weighted median, and MR-Egger methods and performed extensive sensitivity analyses. Additionally, multivariable MR was conducted to evaluate the direct and indirect effects of childhood BMI on TMDs while accounting for BW and adult BMI, and vice versa.

RESULTS

Univariable MR analyses revealed a causal effect of low childhood adiposity on an increased risk of TMDs (childhood BMI: IVW OR: 0.65, 95% CI: 0.54-0.78, p < .001; childhood body size: IVW OR: 0.56, 95% CI: 0.43-0.73, p < .001). No causal association existed between genetically predicted BW, adult BMI, or body fat percentage and TMDs. In the multivariable MR analyses, the effects of childhood BMI on TMDs occurrence remained significant and direct, even after adjusting for BW and adult BMI (multivariable IVW OR: 0.78, 95% CI: 0.61-0.99, p = .048). No pleiotropy and heterogeneity were detected (p > .05).

CONCLUSION

Low childhood BMI might causally increase the risk of TMDs through a direct pathway.

Surgical vs. Non-Surgical Management of Temporomandibular Joint Disorders: Clinical Outcomes

Background

Temporomandibular joint disorders (TMDs) encompass a range of clinical conditions affecting the temporomandibular joint (TMJ) and associated structures. Management approaches for TMDs vary and include both surgical and non-surgical interventions.

Materials and Methods

In this retrospective cohort study, medical records of 150 patients diagnosed with TMDs were reviewed. Patients were categorized into two groups: surgical intervention and non-surgical intervention. The surgical group underwent various surgical procedures, including arthroscopy, arthroplasty, and joint replacement, while the non-surgical group received conservative treatments such as physical therapy, pharmacotherapy, and occlusal splints. Pain levels, TMJ function, quality of life (QoL), and patient satisfaction were assessed at baseline and post-treatment (6 months and 1 year).

Results

At the 6-month follow-up, both groups experienced a significant reduction in pain scores (surgical group: 6.3 ± 1.2 to 2.4 ± 0.9, non-surgical group: 6.1 ± 1.1 to 3.2 ± 1.0). TMJ function improved in both groups (surgical group: 2.5 ± 0.8 to 4.8 ± 0.6, non-surgical group: 2.6 ± 0.7 to 4.2 ± 0.9). QoL scores increased (surgical group: 35.2 ± 4.6 to 50.3 ± 5.1, non-surgical group: 35.5 ± 4.2 to 45.7 ± 4.8), and patient satisfaction rates were high (surgical group: 92%, non-surgical group: 87%) at the 1-year follow-up.

Conclusion

Both surgical and non-surgical management approaches demonstrated significant improvements in pain relief, TMJ function, QoL, and patient satisfaction for individuals with TMDs.

Acute dental malocclusion associated with lateral pterygoid muscle partial tear: Case Report and literature review

BACKGROUND

The article presents a rare case of acute malocclusion produced by a unilateral partial tear of the lateral pterygoid muscle and an up-to-date literature review of the pathology.

CLINICAL PRESENTATION

A 37-year-old female was examined; her chief complaints were pain on the right side of the temporomandibular joint (TMJ) area and mastication impairment associated with major occlusal modifications and anterior open bite. After magnetic resonance imaging (MRI) and cone beam computed tomography (CBCT) of the TMJ and subsequent MRI for soft tissue, the final diagnosis was a partial right lateral pterygoid muscle tear.

CONCLUSION

The case shows the value of combined imaging in temporomandibular disorders (TMD) and the importance of soft tissue evaluation in addition to articular examination, as the primary pathology might lie outside the joint. The authors' review of the current literature did not hitherto reveal a similar case.

Recording the maxillomandibular relationship with the Aqualizer system prior to occlusal splint therapy for treating temporomandibular disorders: a randomized controlled trial

Temporomandibular disorders (TMD) present a public health issue and are one of the most common musculoskeletal conditions causing chronic pain. This study compares the outcomes of occlusal splint therapy in patients with TMD following two different maxillomandibular relationship (MMR) registration techniques. 40 TMD patients were randomly allocated to MMR registration with the Aqualizer system (AQU) or with chin point guidance (CPG) prior to fabricating occlusal splints. TMD symptoms, subjective pain intensity, and quality of life (QoL) were recorded at baseline and after 3 and 6 months. The treatment led to an overall reduction of TMD symptoms in both groups (Conover test, p < 0.00001). TMJ sounds, TMJ pain with palpation and muscle pain with palpation subsided regardless of the type of MMR registration method used (Cohen's d > 0.8). AQU-based occlusal splints led to a better improvement of TMJ pain with maximum opening compared to CPG-based occlusal splints (Cohen's d = 0.9; CPG d = 0.13). In both groups, occlusal splint treatment had little to no effect on correcting lateral mandible deviation or improving restricted jaw opening. After 6 months occlusal splints in both groups had a large effect on improving subjective pain intensity (Cohen's d > 0.8), however, patients reported a higher QoL in the AQU group compared to the CPG group (Mann-Whitney-U-test, p < 0.05). The results of this study support the premise that occlusal splints are effective in relieving pain-related TMD symptoms. The Aqualizer can be considered for determining MMR in cases, where guided registration techniques are not possible.Trial registration: DRKS00031998.

The association of self-reported awake bruxism and sleep bruxism with temporomandibular pain and dysfunction in adult patients with temporomandibular disorders

OBJECTIVE

To investigate the association of the severity of temporomandibular disorders (TMD) pain and dysfunction with the frequency of self-reported awake bruxism (AB), sleep bruxism (SB), and stress in an adult TMD-patient population.

MATERIALS AND METHODS

This cross-sectional study included 237 TMD patients based on the Diagnostic Criteria for TMD. Age, sex, frequency of self-reported AB and SB, and stress were included as independent variables. TMD pain and TMD dysfunction were included as dependent variables in regression analyses. Univariate and multivariable linear regression analyses were used to predict TMD pain and TMD dysfunction in two separate models. Finally, network analysis was performed to investigate the associations between all variables.

RESULTS

In the univariate analyses, TMD pain was significantly associated with self-reported AB-frequent (unstandardized coefficient (B) = 3.196, 95%CI 1.198-5.195, p = 0.002). TMD dysfunction was significantly associated with AB-frequent (B = 2.208, 95%CI 0.177-4.238, p = 0.033) and SB-sometimes (B = 1.698, 95%CI 0.001-3.394, p = 0.050). In the multivariable analyses, TMD pain was significantly associated with TMD dysfunction (B = 0.370, p < 0.001), stress (B=0.102, p < 0.001). TMD dysfunction was significantly associated with TMD pain (B = 0.410, p < 0.001) only. Network analysis showed that TMD pain is a bridge factor between AB, stress, and TMD dysfunction.

CONCLUSIONS

TMD pain is directly associated with AB, stress, and TMD dysfunction, while TMD dysfunction is only associated with TMD pain.

CLINICAL RELEVANCE

Reducing pain may improve pain-related dysfunction, and the management of AB and stress may improve TMD pain and dysfunction, and vice versa.

Validity of a Mobile Application to Diagnose Temporomandibular Disorders

This study aimed to assess the diagnostic accuracy of a mobile application by comparing its diagnoses to those of Orofacial Pain and Oral Medicine specialists and further imaging results (CBCT and MRI) in 500 patients with temporomandibular disorder (TMD). The research focused on three diagnostic categories: the initial specialist diagnoses, the final diagnoses after imaging, and the mobile app's diagnoses. The concordance rates, sensitivities, specificities, and positive predictive values of the diagnoses were examined, with further imaging serving as the gold standard. The mobile app demonstrated a high concordance rate compared to both the final (0.93) and the initial specialists' diagnoses (0.86). The sensitivities, specificities, and positive predictive values also indicated strong reliability, affirming the app's diagnostic validity. Although the concordance rate was slightly lower when comparing the app's diagnoses to the imaging results (CBCT and MRI), the specialists' diagnoses yielded similar results. The study suggests that user-friendly diagnostic mobile applications, based on the diagnostic criteria for TMD, could enhance the clinical management of TMD. Given the reliability of mobile applications for diagnostic purposes, their wider implementation could facilitate the provision of appropriate and timely treatments for patients with TMD.

Test-retest reliability of the isometric contraction test (IC test) of the masticatory muscles in subjects with and without temporomandibular muscle disorders

OBJECTIVE

Recently, the DC/TMD has become an essential tool for the diagnosis of temporomandibular disorders (TMD). However, as they fail to include functional activities, new assessment proposals have emerged, such as the isometric contraction test (IC test) of the masticatory muscles, which uses muscle contractions to identify muscular TMD. This study aimed to determine the test-retest reliability of the IC test.

METHODS

A total of 64 participants (40 women and 24 men) completed the IC test administered by two different physical therapists on two non-consecutive days. Cohen's kappa (k), PABAK, and percent agreement (PA) between days were estimated.

RESULTS

The IC test showed good to excellent test-retest reliability values (k>0.77; PABAK>0.90), both globally and individually for the muscles evaluated, and PA>90%, therefore above the thresholds for clinical applicability. However, the global assessment of myofascial pain and the evaluation of the medial pterygoid muscle showed slightly lower reliability values.

CONCLUSION

The IC test is reliable for the assessment of subjects with muscular TMD, both in terms of the global assessment and the evaluation of each muscle, which supports its clinical applicability. Care should be taken when assessing myofascial pain globally and when evaluating the medial pterygoid in all types of pain.

Potential of ultra-high-resolution CT in detecting osseous changes of temporomandibular joint: experiences in temporomandibular disorders

BACKGROUND

Osseous changes of the temporomandibular joint (TMJ) are related to the progression of temporomandibular disorders (TMD), and computed tomography (CT) plays a vital role in disease evaluation.

OBJECTIVE

The aims of this study were to evaluate the image quality and diagnostic value of ultra-high-resolution CT (U-HRCT) in TMD compared to cone-beam CT (CBCT).

METHODS

TMD patients who underwent both CBCT and U-HRCT between November 2021 and September 2022 were retrospectively included. Image quality scores were assigned for four osseous structures (the cortical and trabecular bones of the condyle, articular eminence, and glenoid fossa) by two independent observers from Score 1 (unacceptable) to Score 5 (excellent). Diagnostic classification of TMD was categorized as follows: Class A (no evident lesion), Class B (indeterminate condition) and Class C (definitive lesion). Image quality scores and diagnostic classifications were compared between CBCT and U-HRCT. The Cohen's Kappa test, Wilcoxon signed-rank test, Chi-square test and Fisher's exact test were conducted for statistical analysis.

RESULTS

Thirty TMD patients (median age, 30 years; interquartile range, 26-43 years; 25 females) with 60 TMJs were enrolled. Image quality scores were higher for U-HRCT than for CBCT by both observers (all Ps < 0.001). Definitive diagnoses (Class A and C) were achieved in more cases with U-HRCT than with CBCT (93.3% vs. 65.0%, Fisher's exact value = 7.959, P = 0.012). Among the 21 cases which were ambiguously diagnosed (Class B) by CBCT, definitive diagnosis was achieved for 17 cases (81.0%) using U-HRCT.

CONCLUSIONS

U-HRCT can identify osseous changes in TMD, providing improved image quality and a more definitive diagnosis, which makes it a feasible diagnostic imaging method for TMD.

Principal component analysis of the biopsychosocial features relevant to temporomandibular disorders

OBJECTIVES

This study aimed to explore the dimensionality of three biopsychosocial constructs with multiple subdimensions, including the Symptom Checklist-90-Revised (SCL-90R), pain catastrophizing scale (PCS) and Pittsburgh Sleep Quality Index (PSQI), and to identify the latent dimensions of five biopsychosocial constructs (SCL-90R, PCS, PSQI, pain severity, and pain interference) using the principal component analysis (PCA) in patients with temporomandibular disorder (TMD).

SUBJECTS AND METHODS

A secondary analysis of a previous cross-sectional study comprising 1488 patients with painful TMD was conducted using multiple questionnaires.

RESULTS

PCA of the SCL-90R and PCS identified one factor, which explained 60.8% and 80.2% of the total variance, respectively. For the PSQI, three factors explained 61.3% of the variance. PCA resulted in two main orthogonal components: factor 1, which comprised a combination of scores for pain severity, pain interference and global scores of PCS, and PSQI; and factor 2, which comprised one measure of the SCL-90R. Factors 1 (46.5%) and 2 (20.0%) explained 66.5% of the total variance.

CONCLUSION

The findings of this study revealed that five measures can be primarily categorised into two latent constructs of the psychological (affective) and pain-related (sensory-cognitive) dimensions. These core components could be applied in clinical settings and for research purposes.

An artificial intelligence model for the radiographic diagnosis of osteoarthritis of the temporomandibular joint

The interpretation of the signs of Temporomandibular joint (TMJ) osteoarthritis on cone-beam computed tomography (CBCT) is highly subjective that hinders the diagnostic process. The objectives of this study were to develop and test the performance of an artificial intelligence (AI) model for the diagnosis of TMJ osteoarthritis from CBCT. A total of 2737 CBCT images from 943 patients were used for the training and validation of the AI model. The model was based on a single convolutional network while object detection was achieved using a single regression model. Two experienced evaluators performed a Diagnostic Criteria for Temporomandibular Disorders (DC/TMD)-based assessment to generate a separate model-testing set of 350 images in which the concluded diagnosis was considered the golden reference. The diagnostic performance of the model was then compared to an experienced oral radiologist. The AI diagnosis showed statistically higher agreement with the golden reference compared to the radiologist. Cohen's kappa showed statistically significant differences in the agreement between the AI and the radiologist with the golden reference for the diagnosis of all signs collectively (P = 0.0079) and for subcortical cysts (P = 0.0214). AI is expected to eliminate the subjectivity associated with the human interpretation and expedite the diagnostic process of TMJ osteoarthritis.

Intraobserver reliability and validity of a single ultrasonic measurement of the lateral condyle-capsule distance in the temporomandibular joint

PURPOSE

The purpose of the study was to examine the reliability and validity of a single lateral condyle-capsule distance (LCCD) measurement while saving on economic costs and clinical resources.

METHODS

A longitudinal test-retest design was used to assess the reliability and validity of single-examiner measures over 72 TMJ sonographic analyses. Intraclass correlation coefficients (ICC) and a Bland-Altman plot were used to study reliability and validity, comparing the first measurement of the LCCD to the mean of 3 measurements taken one week later by the same examiner.

RESULTS

ICC show intraobserver reliability of 0.981, 95% confidence intervals (CI) of 0.969 to 0.988. The mean difference between the ultrasound measurements is 0.019 mm (95% CI 0.0005-0.0383) with a standard deviation of 0.080 mm, demonstrating robust validity. The 95% Limits of Agreement (LoA) are - 0.138 for the lower limit and 0.177 for the upper. Mean relative error is 0.009 mm.

CONCLUSION

Intraobserver reliability of a trained examiner is very high in the single measurement of the LCCD and validity is significant compared to more complex methods. The risk of bias is low since the mean of three LCCD measurements is calculated as opposed to recording only one single measurement.

The biopsychosocial model: Its use and abuse

The biopsychosocial model (BPSM) is increasingly influential in medical research and practice. Several philosophers and scholars of health have criticized the BPSM for lacking meaningful scientific content. This article extends those critiques by showing how the BPSM's epistemic weaknesses have led to certain problems in medical discourse. Despite its lack of content, many researchers have mistaken the BPSM for a scientific model with explanatory power. This misapprehension has placed researchers in an implicit bind. There is an expectation that applications of the BPSM will deliver insights about disease; yet the model offers no tools for producing valid (or probabilistically true) knowledge claims. I argue that many researchers have, unwittingly, responded to this predicament by developing certain patterns of specious argumentation I call "wayward BPSM discourse." The arguments of wayward discourse share a common form: They appear to deliver insights about disease gleaned through applications of the BPSM; on closer inspection, however, we find that the putative conclusions presented are actually assertions resting on question-begging arguments, appeals to authority, and conceptual errors. Through several case studies of BPSM articles and literatures, this article describes wayward discourse and its effects. Wayward discourse has introduced into medicine forms of conceptual instability that threaten to undermine various lines of research. It has also created a potentially potent vector of medicalization. Fixing these problems will likely require reimposing conceptual rigor on BPSM discourse.

Bibliometric Analysis of Research on Temporomandibular Joint and Occlusion from 2000 to 2022

Purpose

This study conducted a bibliometric analysis that comprehensively described publications on temporomandibular joint and occlusion from 1 January 2000 to 31 October 2022, aiming to reveal hotspots and predict future research trends.

Methods

A total of 2985 articles and reviews were retrieved from Web of Science Core Collection (WoSCC). Excel 2019, VOSviewer and CiteSpace software were used for visualizing analysis of research trends, authors, journals, institutions, countries, keywords and cited references.

Results

Both the annual publication counts and citation times increased significantly. Wang MQ was the most active author. Moreover, Manfredini D and Okeson JP were the most influential two. Journal of Oral Rehabilitation was the core journal. University of Sao Paulo was the most productive institutions. "Temporomandibular disorders" (TMDs), "temporomandibular joint" and "occlusion" were the top 3 keywords with the most frequencies. Keywords and references with burst showed that the causes of TMDs, diagnosis and treatments for TMDs as well as bruxism may be hotspots currently and in the future.

Conclusion

In this study, the research trends, the most productive and influential authors, journals, institutions, countries, in addition to keywords and cited references with burst in the field of temporomandibular joint and occlusion were revealed by a bibliometric analysis, which could help scholars to understand recent hotspots and future trends.

Overtreatment "Successes"--What Are the Negative Consequences for Patients, Dentists, and the Profession?

AIMS

To describe how some management practices in the field of orofacial musculoskeletal disorders (also described as temporomandibular disorders [TMDs]) are based on concepts about occlusal relationships, condyle positions, or functional guidance; for some patients, these procedures may be producing successful outcomes in terms of symptom reduction, but in many cases, they can be examples of unnecessary overtreatment.

METHODS

The authors discuss the negative consequences of this type of overtreatment for both doctors and patients, as well as the impact on the dental profession itself. Special focus is given to trying to move the dental profession away from the old mechanical paradigms for treating TMDs and forward to the more modern (and generally more conservative) medically based approaches, with emphasis on the biopsychosocial model.

RESULTS

The clinical implications of such a discussion are apparent. For example, it can be argued that the routine use of Phase II dental or surgical treatments for managing most orofacial pain cases represents overtreatment, which cannot be defended on the grounds of symptom improvement (ie, "successful" outcomes) alone. Similarly, there is enough clinical evidence to conclude that complex biomechanical approaches focusing on the search for an ideal specific condylar or neuromuscular position for the management of orofacial musculoskeletal disorders are not needed to produce a positive clinical result that is stable over time.

CONCLUSION

Typically, overtreatment successes cannot be easily perceived by the patients or the treating dentists because the patients are satisfied and the dentists feel good about those outcomes. However, neither party knows whether an excessive amount of treatment has been provided. Therefore, both the practical and ethical aspects of this discussion about proper treatment vs overtreatment deserve attention.

Four-dimensional digital design to prediction of the real-time functional rehabilitation in the esthetic zone

Recent developments in digital technology and materials have improved the accuracy and efficiency of tracking and recording mandibular motion, with various methods being described. The present article describes a digital workflow with complete and accurate 3-dimensional spatial trajectories of mandibular motion to direct the design of lingual restorations. The workflow allowed the lingual curvature of the restoration to conform with the distinctive trajectory of mandibular protrusion.

Do TMJ MRI diagnosis support clinical examination diagnosis following DC/TMD criteria?

PURPOSE

The Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) has been validated as a clinical diagnostic guideline with high-sensitivity and -specificity in identifying TMDs. The purpose of this study was to evaluate the agreement between DC/TMD diagnoses and magnetic resonance imaging (MRI) diagnoses in patients with TMD.

METHODS

A prospective cohort study was conducted on patients with TMD. The predictor variable was the clinical diagnosis of TMD based on DC/TMD criteria. The outcome variable was the MRI diagnosis of TMD. The diagnoses used for both the predictor variable and the outcome variable were the same. They were normal, disc displacement with reduction (DDWR), DDWR with intermittent locking, disc displacement without reduction (DDWOR) with limited opening, DDWOR without limited opening, degenerative joint disease, and subluxation. Age and gender of the patients and number of joints evaluated were covariates. Each subject had clinical examination performed by two independent Oral and Maxillofacial Surgeons. All subjects had a bilateral temporomandibular joint (TMJ) MRI performed which was evaluated by a radiologist. The correlation between the clinical and MRI diagnoses was calculated using Cohen's kappa value with a P value of <.05 considered significant.

RESULTS

A total of fifty patients (100 TMJs) were enrolled with 38 females and 12 males. The mean ages were 31.92 and 31.75 years, respectively, with a total of 100 TMJs analyzed. Internal derangement was clinically identified in 76% of the joints and with MRI in 69% of joints. The Cohen's kappa value between DC/TMD and MRI diagnoses was found to be κ = 0.720 (P < .01). The respective sensitivity and specificity in determining disc position clinically for DDWR was 1 and 0.96; for DDWR with intermittent locking 0.78 and 0.91; for DDWOR with limited opening 0.9 and 0.98; for DDWOR without limited opening 1 and 0.9; for degenerative joint disease 0.63 and 0.97 and for subluxation 0.28 and 1.00.

CONCLUSION

The DC/TMD clinical examination performed well in all types of disc displacement but is less reliable in detecting the presence of degenerative disc diseases and subluxation.

Masticatory Function in Individuals with Temporomandibular Disorders: A Systematic Review and Meta-Analysis

The literature search was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) protocol in the PubMed, Cochrane Library, LILACS, EBSCO, Scielo, between 2012 and 2022. The methodological quality was assessed by using the Newcastle-Ottawa Study Quality Assessment Scale. Mean differences and 95% confidence intervals were calculated and combined in meta-analyses. A total of 1202 participants were included in this systematic review (690 with TMD; 512 without TMD), with 22 articles being included in the qualitative analysis. Only three studies enabled the comparative analysis of the results. Ten articles showed a high methodological quality and a low risk of bias, and twelve had a low methodological quality and an increased risk of bias. The meta-analysis showed that the differences between the intervention and control groups were not statistically significant for the percentage overlapping coefficient of the anterior temporal muscle, for the masseter, and for the torque coefficient. The parameters analyzed with the compound technique for chewing showed altered mandibular functions in individuals with TMD. With the EMG method, it was possible to suggest that TMD in adult individuals causes compensatory muscle behaviors, and several changes in the masticatory function were found.

Galectin-8 involves in arthritic condylar bone loss via podoplanin/AKT/ERK axis-mediated inflammatory lymphangiogenesis

OBJECTIVE

The lymphatic system plays a crucial role in the maintenance of tissue fluid homeostasis and the immunological response to inflammation. Galectin-8 (Gal-8) regulates pathological lymphangiogenesis but the effects of which on inflammation-related condylar bone loss in temporomandibular joint (TMJ) have not been well studied.

DESIGN

We used TNFα-transgenic (TNF^TG) mice and their wildtype (WT) littermates to compare their inflammatory phenotype in TMJs. Next, lymphatic endothelial cells (LECs) were used to examine the effects of which on osteoclast formation, pro-inflammatory factor expression, and inflammatory lymphangiogenesis with or without thiodigalactoside (TDG, a Gal-8 inhibitor) treatment. At last, two murine models (TNF^TG arthritic model and forced mouth opening model) were used to explore TDG as a potential drug for the treatment of inflammation-related condylar bone loss.

RESULTS

In comparison to WT mice, lymphatic areas of lymphatic vessel endothelial receptor 1 (LYVE1)⁺/podoplanin (PDPN)⁺ and Gal-8⁺/PDPN⁺, TRAP-positive osteoclast number, and condylar bone loss are increased in TNF^TG mice. Inhibition of Gal-8 in LECs by TDG, reduces TNFα-induced osteoclast formation, pro-inflammatory factor expression, and inflammatory lymphangiogenesis. In addition, Gal-8 promotes TNFα-activated AKT/ERK/NF-κB pathways by binding to PDPN. Finally, the administration of TDG attenuates inflammatory lymphangiogenesis, inhibits osteoclast activity, and reduces condylar bone loss in TNF^TG arthritic mice and forced mouth opening mice.

CONCLUSIONS

Our findings reveal the important role of Gal-8-promoted pathological lymphangiogenesis in inflammation-related condylar bone loss.

Effects of Physiotherapy on Pain and Mouth Opening in Temporomandibular Disorders: An Umbrella and Mapping Systematic Review with Meta-Meta-Analysis

The aim of this meta-meta-analysis was to assess the current evidence regarding the effect of physical therapy (PT) interventions on pain and functional variables in temporomandibular disorders (TMD). We conducted an umbrella systematic review (SR) and four meta-meta-analyses (MMA) and created an evidence map to determine the effectiveness of PT on pain intensity and maximum mouth opening in patients with TMD. The quality of the included SR was assessed with the AMSTAR 2, and the risk of bias with ROBIS. Of the 31 SR included in the umbrella SR, only 10 were included in the MMA. The MMA showed moderate effects for manual therapy and therapeutic exercise, and large effects for low-level laser therapy on improving pain intensity and maximum mouth opening in patients with TMD, with a limited to moderate quality of evidence. The overlapping analyses showed only a slight overlap for all the MMA according to the corrected covered area (range from 0.07 to 0.2), 23.1% to 41.6%. This umbrella SR showed that manual therapy and exercise interventions, as well as low-level laser therapy interventions, are effective in the reduction in pain intensity and improvement of maximum mouth opening in TMD. This article presents a synthesis of the available evidence related to the various physical therapy interventions used in patients presenting with temporomandibular disorders. These results could help clinicians to select the optimal intervention for their patients and to reject those that are less useful.

Craniofacial Morphology of Temporomandibular Disorder Patients with Different Disc Positions: Stratifying Features Based on Sex and Sagittal Skeletal Pattern

Disc displacement (DD) appears in the majority of temporomandibular disorder (TMD) patients. The correlation between craniofacial morphology and different disc positions has been underlined, while the craniofacial morphological differences based on sex and sagittal skeletal pattern stratification have been insufficiently studied. In this study, 304 patients with TMD complaints were included and classified into normal position, disc displacement with reduction (DDwR) and disc displacement without reduction (DDwoR) groups according to magnetic resonance imaging. A total of 24 cephalometric measurements, covering the cranial base, vertical relationship, sagittal relationship, mandible position and morphology, and dental relationship, were assessed using lateral cephalograms. A stratified analysis was performed based on the sex and sagittal skeletal pattern. Overall, DD patients had distinctive craniofacial morphological features. The posterior cranial base length and mandibular arc angle were statistically different only in females, while the Y-axis angle, occlusal plane angle and sella nasion point A angle (SNA) might be unique features in males. Skeletal class II had the most statistically different measurements compared to the others. Differences in the Frankfort mandibular incisor angle (FMIA) and saddle angle were especially displayed in skeletal class III patients. The sex and skeletal sagittal pattern could affect the morphological differences in TMD patients with different disc positions.

The association between forward head posture and masticatory muscle pressure pain thresholds in patients with temporomandibular joint dissorders: a cross-sectional observational study

OBJECTIVES

Forward head posture (FHP) is common in patients with temporomandibular joint disorders (TMDs); however, whether it contributes to TMD symptoms remains unclear. The aim of this study was to investigate the association between (1) FHP and masticatory muscle pressure pain thresholds (PPTs) and (2) neck muscle and masticatory muscle PPTs.

MATERIALS AND METHODS

A total of 145 patients diagnosed with TMD were recruited between December 2020 and April 2021. Data regarding FHP and neck and masticatory muscle PPTs were collected. FHP was characterized by the craniocervical angle (CVA) measured between the horizontal line through C7 and the line between the tragus of the ear and C7. Patients were divided into either the FHP group (CVA ≤ 51°) or the non-FHP group. Differences in the masseter and temporalis muscle PPTs between the two groups were analyzed using the Mann-Whitney U test. The correlation between the CVA, neck, and masticatory muscle PPTs in all patients was determined by Spearman's correlation analysis.

RESULTS

There were 70 patients in the FHP group and 75 patients in the non-FHP group. No significant difference in masseter and temporalis muscle PPTs was found between the two groups (p > 0.05). No correlation was found between FHP and masticatory muscle PPTs (p > 0.05). A significant association was found between the neck muscle and masticatory muscle PPTs (p < 0.05). The C5-C6 pillar and masticatory PPTs were either moderately (r = 0.435, masseter muscle) or strongly (r = 0.608, temporalis muscle) correlated, while the correlation between the trapezius and masticatory muscles was moderate (r = 0.378, masseter muscle and r = 0.461, temporalis muscle).

CONCLUSION

FHP was not directly associated with masticatory muscle PPTs. Masticatory muscle PPTs were strongly or moderately associated with neck muscle PPTs. Therefore, the presence of neck pain, not the degree of FHP, in patients with TMD is of significance.

CLINICAL RELEVANCE

In TMD treatment, we should pay attention to and actively relieve neck pain.

Application of photobiomodulation for chronic pain-related TMD on pain points versus pre-established points: Randomized clinical trial

Photobiomodulation therapy (PTB) is a therapeutic possibility for temporomandibular disorders (TMD), but its effectiveness and protocols for use remain controversial. This study is a RCT that compared the effectiveness of PTB on pain points of the masticatory muscles and TMJs, located through palpation versus application of pre-established points in women with painful TMD, diagnosis by DC/TMD (Diagnostic Criteria for Temporomandibular Disorders - Brazilian Portuguese version). Therefore, a total sample of 54 women, aged between 18 and 60 years, was investigated. Volunteers were randomly randomized and PTB was applied in four different groups with a dose of 4 J and 6 J divided into pre-established application points (PE - G1) and pain points (PD - G2) - Groups 4PE, 4PD, 6PE and 6PD. Four laser applications were performed with a wavelength of 780 nm, one session per week, totaling one month of therapy. The following assessments were performed: DC/TMD, Brief Pain Inventory (BPI), McGill Questionnaire - Short Version (SF-MPQ) and Pain Intensity, Visual Analogue Scale (VAS). Friedman's test was used for within-group comparisons, while the Mann-Whitney test was used for between-group comparisons (p < 0.05). According to the results, laser application on pain points (G2) was more effective. McGill's results showed that regardless of dose, the pain point application group had better outcomes (p = 0.004). Pain intensity evaluation (last days) also showed that application at the pain points was more effective regardless of dose (p = 0.0002). Medians and interquartile deviations showed overall that PTB was more effective at pain points, with a trend towards better outcomes at the 6 J dose. Therefore, it can be concluded that in women with chronic painful TMD, the application of PTB at pain points is more effective than the application at pre-established points. Therefore, individualized PTB protocols are proposed, based on examination palpation of the masticatory structures.

Extracellular vesicles in osteoarthritis of peripheral joint and temporomandibular joint

Osteoarthritis (OA) is a disabling disease with significant morbidity worldwide. OA attacks the large synovial joint, including the peripheral joints and temporomandibular joint (TMJ). As a representative of peripheral joint OA, knee OA shares similar symptoms with TMJ OA. However, these two joints also display differences based on their distinct development, anatomy, and physiology. Extracellular vesicles (EVs) are phospholipid bilayer nanoparticles, including exosomes, microvesicles, and apoptotic bodies. EVs contain proteins, lipids, DNA, micro-RNA, and mRNA that regulate tissue homeostasis and cell-to-cell communication, which play an essential role in the progression and treatment of OA. They are likely to partake in mechanical response, extracellular matrix degradation, and inflammatory regulation during OA. More evidence has shown that synovial fluid and synovium-derived EVs may serve as OA biomarkers. More importantly, mesenchymal stem cell-derived EV shows a therapeutic effect on OA. However, the different function of EVs in these two joints is largely unknown based on their distinct biological characteristic. Here, we reviewed the effects of EVs in OA progression and compared the difference between the knee joint and TMJ, and summarized their potential therapeutic role in the treatment of OA.

Professional Factors Associated with Case Resolution without Referrals of Orofacial Pain Cases to Secondary Dental Care by Telehealth in Brazil: A Cross-Sectional Study in 2019 and 2020

This study aimed to identify professional factors associated with case resolution without a referral of orofacial pain to secondary health care by Brazilian Primary Health Care (PHC) practitioners who demanded asynchronous teleconsulting, stratified by year, in 2019 and 2020 (the COVID-19 Pandemic burst). A cross-sectional study employed secondary databases from asynchronous teleconsulting Telehealth Brazil Networks from January 2019 to December 2020. The outcome was the dichotomous variable "If referral to secondary care was avoided." As covariates: sex, healthcare professions, and category of orofacial pain doubts. A negative binomial regression model estimated each covariate's unadjusted and adjusted PR (95%CI) and p values, stratified for 2019 and 2020. There was a difference in descriptive factors associated with case resolution without a referral from 2019 to 2020. Females prevailed in both years, and the total demand decreased to a third from 2019 to 2020. The rate of resoluteness decreased by 19.1%. In 2019, nurses (PR = 0.69 CI 95% 0.57-0.83) and other professionals (PR = 0.84 CI 95% 0.73-0.97) showed less frequency of case resolution without a referral than did general dentists. In 2020, oral-cavity-related doubts (PR = 1.18 CI 95% 1.06-1.32) and temporomandibular disorders (PR = 1.33 95% 1.15-1.54) surpassed other causes of orofacial pain in case resolution without a referral, and female professionals avoided referrals more frequently than men (PR = 1.24 CI 95% 1.21-1.38). In conclusion, in 2019, oral cavity doubts and the PHC profession influenced the case resolution. Female professionals and oral cavity doubts scored the higher case resolution without a referral for the service in 2020.

Effectiveness of Physiotherapy in the Treatment of Temporomandibular Joint Dysfunction and the Relationship with Cervical Spine

Temporomandibular dysfunctions are a heterogeneous group of conditions involving the temporomandibular joints (TMJs) and periarticular musculoskeletal structures. This study aimed to evaluate the effectiveness of a physiotherapy program for TMJ dysfunctions and the relationship with cervical spine. The study design was a non-randomized clinical trial with two parallel treatment groups: 33 subjects in the experimental group that underwent conservative drug treatment and physiotherapy treatment, and 31 subjects in the control group that underwent only conservative drug treatment. The participants were examined at baseline and re-examined after 3 months. In this study there was a higher incidence of female subjects. After 3 months of treatment of the TMJs and cervical spine, pain decreased in both groups (p = 0001). Muscle testing at the cervical spine and temporomandibular level showed a decrease in pain and muscles spasms. The average percentage values of the Neck Disability Index (NDI) and the Jaw Functional Limitation Scale 8 (JFLS 8) decreased significantly in both groups, but especially in the experimental group (p = 0.001). Physiotherapy treatments could maintain the functional state at the temporomandibular and cervical levels, thus contributing to increasing the quality of daily life.

Oral health-related quality of life in patients with osteoarthritis of the temporomandibular joint-Results of a systematic review

OBJECTIVES

The aim of this systematic review was to assess the oral health-related quality of life (OHRQoL) of patients with osteoarthritis (OA) of the temporomandibular joint (TMJ).

METHODS

This systematic literature search applied the search terms "oral health-related quality of life AND osteoarthritis of jaw OR arthritis of temporomandibular joint AND oral health-related quality of life" in PubMed, Medline, Web of Science and Scopus. Eligibility criteria were publication until 31 August 2021, examination of children or adults with OA of TMJ, reporting of any OHRQoL measurement and a full text in English language. Two different, independent and experienced reviewers performed this systematic literature search. The analysis of respective data was qualitative. For quality appraisal, the available checklist from the Agency for Healthcare Research and Quality (AHRQ) was applied.

RESULTS

Out of 102 findings, eight studies were included in qualitative analysis. Seven clinical investigations were performed in adults aged between 34 and 43 years. The other included study was performed on children. The quality of two studies was moderate, and six studies were evaluated as of high quality. Most studies applied the 14-item short form of the oral health impact profile (OHIP 14) for assessment of OHRQoL. OHIP 14 ranged between 9.24 and 38.86 points in means of sum score. Comparison with healthy individuals revealed worse OHRQoL of OA patients in two studies. Associations between OHRQoL with either oral health, general quality of life or disease-related parameters were rarely reported and heterogeneous. Five of the included studies reported subscales of OHIP 14, showing an impairment in all subscales.

CONCLUSIONS

There are hints that patients with OA of the TMJ show a reduced OHRQoL. More studies are needed, especially regarding oral health, disease-related parameters and pain intensity and its potential influence on OHRQoL.

Sex dependent differences of temporomandibular condylar bone mineral density distribution

OBJECTIVE

The objective of this study was to examine whether bone mineral density (BMD) distribution in the mandibular condyle and facial morphology are associated with temporomandibular joint osteoarthritis (TMJ OA) using clinical cone beam computed tomography (CBCT) images.

METHODS

CBCT images of 35 adults (16 male and 19 female) were examined to obtain TMJ OA counts, cephalometric analyses, and histograms of gray values that are proportional to BMD. Mean, standard deviation (SD), and low and high gray values at the 5th and 95th percentiles (Low5 and High5) of the histograms were measured.

RESULTS

The female group had significantly higher values of TMJ OA counts, mean, and SD on the right mandibular condyle, High5 on both sides, and all gray value parameters for total (right + left) than the male group.

CONCLUSION

Comprehensive analysis of BMD distribution in the mandibular condyle can provide useful information for prognosis of TMJ OA.

Chronic temporomandibular disorders are associated with higher propensity to develop central sensitization: a case-control study

ABSTRACT

Temporomandibular disorders (TMD) include a group of musculoskeletal disorders that may involve increased responsiveness of nociceptive neurons in the central nervous system (ie, central sensitization). To test this hypothesis further, this study examined whether, as compared with healthy subjects, patients with chronic TMD have a greater propensity to develop secondary mechanical hyperalgesia-a phenomenon that can be confidently attributed to central sensitization. In this case-control study, we assessed the area of secondary mechanical hyperalgesia induced experimentally by delivering high-frequency electrical stimulation (HFS) to the volar forearm skin in 20 participants with chronic TMD and 20 matched healthy controls. High-frequency electrical stimulation consisted in 12 trains of constant-current electrical pulses (5 mA) delivered at 42 Hz. The area of secondary mechanical hyperalgesia was evaluated 30 minutes after applying HFS. The area of secondary mechanical hyperalgesia induced by HFS was on average 76% larger in the chronic TMD group (M = 67.7 cm 2 , SD = 28.2) than in the healthy control group (M = 38.4 cm 2 , SD = 14.9; P = 0.0003). Regarding secondary outcomes, there was no group difference in the intensity of secondary mechanical hyperalgesia, but allodynia to cotton after HFS was more frequent in the chronic TMD group. To the best of our knowledge, this is the first study to show that individuals with chronic TMD have an increased propensity to develop secondary hyperalgesia in a site innervated extratrigeminally. Our results contribute to a better understanding of the pathophysiology of chronic TMD.

Psychological Profiles and Their Relevance with Temporomandibular Disorder Symptoms in Preorthodontic Patients

Background

Temporomandibular disorders (TMDs) refer to a group of heterogenous musculoskeletal diseases with diverse clinical symptoms and an undetermined aetiology. The psychological profiles were closely related to the onset and treatment outcomes of TMDs.

Objective

To examine the relevance between psychological profiles and different symptoms of TMDs in preorthodontic patients.

Methods

The study was conducted among 570 preorthodontic patients. TMDs symptoms were recorded by the Diagnostic Criteria for TMD (DC/TMD) symptom questionnaire. The seven-item Generalized Anxiety Disorder Scale (GAD-7), the nine-item Patient Health Questionnaire (PHQ-9), and the Pain Catastrophizing Scale (PCS) were used for the evaluation of anxiety, depression, and pain catastrophizing levels. The relevance of three psychological profiles with TMDs and subtypes was evaluated with Spearman's rank correlation test and logistic regression analysis (P < 0.05).

Results

34.56% of the enrolled preorthodontic patients were diagnosed with TMDs. Scores of GAD-7, PHQ-9, and PCS were significantly higher in the TMDs group than in the non-TMDs group. Participants with anxiety, depression, or high pain catastrophizing had a higher prevalence of both pain-related TMDs symptoms and intra-articular TMDs symptoms. The correlations among pain-related TMDs, intra-articular TMDs, and scores on the psychological scales were significant (P < 0.05). The adjusted logistic regression model revealed that anxiety, depression, and high pain catastrophizing were significant risk factors for TMDs with an odds ratio (OR) of 2.196, 1.741, and 1.601, respectively. Depression was associated with higher pain-related TMDs prevalence (OR = 2.136), while anxiety and depression were associated with higher intra-articular TMDs prevalence (OR = 2.341 and 1.473).

Conclusion

Anxiety, depression, and high pain catastrophizing were comorbid psychological conditions of TMDs. Depression was the top risk factor for pain-related TMDs, while anxiety rendered the highest risk for intra-articular TMDs. Inclusion of psychological assessments in preorthodontic evaluation might yield great benefits in TMDs screening.

The 50 most-cited articles on temporomandibular disorders: A bibliometric analysis

BACKGROUND

Temporomandibular disorders (TMD) are musculoskeletal conditions involving masticatory muscles and temporomandibular joints. Bibliometric analysis has been introduced as a new method for collecting and analyzing information on scientific articles.

OBJECTIVE

The aim of this study was to identify the 50 most cited articles on TMD, performing a bibliometric analysis of the identified papers to favor research and clinical practice.

METHODS

On December 17, 2021 a systematic research was performed to find all papers on TMD published in the literature. The Incites Journal Citation Reports dataset and Scopus database was used to obtain bibliometric indexes of the authors and metrics data of the journals, including Impact Factor, Eigenfactor Score, and Normalized Eigenfactor. VOSviewer was used to visualize the keyword mapping networking, with the nodes standing for keywords and the edges for keyword relationships.

RESULTS

Out of 24372 papers obtained by the search strategy, the 50 most cited articles on TMD were analyzed. The paper with the highest number of citations (n= 3020) was on TMD research diagnostic criteria. Rate of citations per year collected by the 50 most cited articles on TMD has been increasing over time (from 627 in 2006 to 1483 in 2021). Most of them were cross-sectional studies (n= 20; 40.0%) and narrative reviews (n= 14; 28.0%).

CONCLUSION

This bibliometric study showed an increasing number of citations for articles on TMD, testifying a high interest in the last years. Starting from this analysis, future studies might provide high-quality evidence on TMD management.

Prevalence of psychological disorders in patients with temporomandibular disorders: A systematic review and meta-analysis

STATEMENT OF PROBLEM

Temporomandibular disorders (TMDs) affect the muscles of mastication, the temporomandibular joint, and associated structures. They are generally classified as muscular or articular and are the main cause of pain in the orofacial region, eventually causing psychological problems. However, the real burden of psychological disorders is unknown.

PURPOSE

The purpose of this systematic review and meta-analysis was to assess the prevalence of psychological disorders in patients with TMDs.

MATERIAL AND METHODS

The study was conducted through a bibliographic search carried out without initial limit until July 2021 in the following electronic databases: MEDLINE/PubMed, Scopus, and PsycINFO. Clinical observational studies investigating depression and somatization in patients with TMD diagnosed by the Diagnostic Research for Temporomandibular Disorders (RDC/TMD) criteria in muscular, articular, and disc disorders were included. A descriptive analysis of the included studies and a meta-analysis for the prevalence data were performed for the synthesis of evidence.

RESULTS

A total of 2320 studies were found, of which 48 complete articles were assessed for eligibility and 22 were included in the analysis. The general prevalence of depression and moderate and severe somatization in patients diagnosed with TMD was estimated at 43.0% (95% confidence interval (CI), 36.0% to 50.0%) and 60.0% (95% CI 52.0 - 67, 0%). The average overall score for depression was estimated at 0.92 (95% CI, 0.69-1.15), being classified as moderate depression. The average overall score for somatization was estimated at 1.09 (95% CI, 0.81-1.36), being classified as severe somatization. All analyses showed high heterogeneity (I2>90%). Based on the quality assessment, 80.9% of studies included in the review had low to moderate risk of bias.

CONCLUSIONS

Patients with TMDs who seek clinical care show a high prevalence of depression and somatization.

Prevalence and characteristics of referred pain in patients diagnosed with temporomandibular disorders according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) in Sharjah, United Arab Emirates

BACKGROUND

Referred pain often complicates and delays the diagnosis of temporomandibular disorders (TMD). Elaborating the prevalence and characteristics of TMD-associated referred pain as well as the distribution of referred pain in different TMD classes will significantly improve the diagnostic process. The objectives of the present study were to assess the prevalence and to evaluate the characteristics of referred pain associated with TMD diagnosed according to the DC/TMD.

METHODS

A total of 252 patients were evaluated using the DC/TMD Axes-I and -II assessment tools. Different modalities were used to treat the diagnosed TMD. Referred pain was diagnosed when the location of the perceived pain in response to palpation extended beyond the boundary of the structure that was examined. For pain locations that were perceived as deep, patients were asked to locate the surface of the area of pain. The result of the assessment was identified as positive if the patient described his perceived pain during the clinical examination as being familiar pain that was experienced in the same location in the last 30 days.  Results: TMD-associated referred pain was recorded in 153 patients (60.7%). The most common referred pain location was the temporal area (45.2%), followed by the ear (42.1%). The referred pain was recorded in disc displacement with reduction with intermittent locking and myofascial pain with referral in all patients (100%). The proportion of patients with referred pain was significantly different between the different TMD diagnostic subgroups (P < 0.001).  The recorded percentage of improvement in the referred pain following the treatment was 50.41% after 3 months and 56.65% after 6 months.

CONCLUSIONS

Referred pain is a prominent feature of TMD. The prevalence of referred pain associated with TMD was 60.7%.  A strong strength association between the different diagnostic subgroups and the presence of referred pain existed.

Validity of the Isometric Contraction Test of the Masticatory Muscles for Diagnosis of Muscular Temporomandibular Disorders

In recent years, the Diagnostic Criteria for Temporomandibular Pain Disorders (DC/TMD) has been questioned, mainly because of the dependence on the muscular pressure needed to be applied during the clinical examination. Therefore, it is necessary to establish improvements in diagnostic strategies for DC/TMD of axis I. The aim of this study was to determine the validity of the Isometric Contraction Test of the masticatory muscles (ICTest) to diagnose DC/TMD of axis I. Forty (n = 40) patients with muscular TMD (myalgia in any of its subtypes), as well as forty age and sex matched controls, participated. They were diagnosed according to DC/TMD of axis I and performed the ICTest in a single session. Sensitivity, specificity, positive (PPV) and negative predictive values (NPV), and positive (LR+) and negative likelihood ratios (LR−) of the ICTest compared with the DC/TMD of axis I were calculated. The ICTest showed a specificity of 95% for the diagnosis of myalgia, and between 94.9% and 96.8% for all subtypes in relation to the DC/TMD of axis I. For sensitivity, lower values were obtained, that is, 90.0% for myalgia, and losing sensitivity depending on the type of myalgia. The LR+ was over 10 for all diagnoses, with the exception of myofascial pain with referral, which was lower. When addressing the LR−, the myofascial diagnosis was the only one below 0.2. According to the results, the ICTest could be considered a valid procedure to diagnose subjects with muscular TMD in a clinical setting.

The Global Need for Easy and Valid Assessment Tools for Orofacial Pain

The World Health Organization recently adopted a historic resolution (WHA74.5) on the urgent need for global oral health improvement. This resolution is particularly relevant in the perspective of the high prevalence of untreated oral diseases. However, one important aspect has been mentioned only in passing, namely that poor oral health often leads to orofacial pain, which is the most common reason for emergency dental visits worldwide. Therefore, an evidence-based decision-making process on oral health should include data related to orofacial pain complaints. To that end, the availability of reliable and valid assessment tools of orofacial pain and related treatment outcomes is essential. INfORM (International Network for Orofacial Pain and Related Disorders Methodology) of the International Association for Dental Research has been one of the driving forces behind the development and implementation of comprehensive sets of tools for such assessments. However, as a prerequisite for the desired global implementation, reliable and valid tools that are also brief, easy to translate, and culturally adaptable need to be further developed and tested. Some of the groundwork to facilitate this process has already been carried out. In addition, a working group within INfORM has developed a short clinical assessment tool for orofacial pain diagnostics that is near completion and will soon be ready for dissemination. Ultimately, reliable and valid orofacial pain assessment is a necessary step toward the development and implementation of appropriate "best buy" interventions that address this major driver of need for oral health care worldwide.

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.