Temporomandibular disorders: Old ideas and new concepts

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.

Interprofessional care for temporomandibular joint disorders: the patient's perspective

The Indiana University School of Dentistry TMJ Institute is a multidisciplinary clinic designed to support the management of patients with challenging temporomandibular disorders. Professionals across dentistry, medicine, physical therapy, and social work collaborate to create a customised, interprofessional consensus to patient care. Compared with traditional, siloed healthcare models, are patients diagnosed with TMJ dysfunction satisfied with the quality of care received from an interprofessional approach? The objective of this study is to determine the level of patient satisfaction at the Institute using a 5-Point Likert scale patient questionnaire. A total of 93 questionnaires were distributed and 84 were collected. A total of 43% of patients travelled over 50 miles to be seen at the Institute. 'Strongly agree' was the most selected response for each prompt. The exception was whether patients preferred to meet with each clinician individually, to which 'strongly disagree' or 'disagree' was the most popular response, indicating that an interprofessional approach was preferred. The results and comments provided by patients revealed that most patients diagnosed with TMJ dysfunction were highly satisfied with the interprofessional approach used at the TMJ Institute. Our study suggests that positive patient satisfaction is an important factor in assessing the quality and efficacy of interprofessional, patient-centred clinic models.

Morphological description of the temporomandibular joint ligaments in domestic pigs

The temporomandibular joint (TMJ) ligaments play crucial roles in its function or dysfunction. The objective of this study was to describe the macro and microscopic morphology of these ligaments in domestic pigs, aiming to: (1) expand knowledge about the species; (2) provide anatomical references for advancing veterinary therapy and utilizing pigs as animal models in craniofacial research. Heads of young Sus scrofa domesticus were dissected to identify TMJ ligaments. Fragments of these ligaments were collected and processed for subsequent histological analysis with Haematoxylin and eosin staining. The results were qualitatively described. Pigs exhibited a TMJ reinforced by three individualized capsular ligaments: a lateral ligament, attaching to the ventral margin of the zygomatic process of the temporal bone and the lateral margin of the mandibular neck; a caudomedial ligament, attaching to the retroarticular process of the squamous part of the temporal bone and the caudomedial margin of the mandibular neck and a caudolateral ligament, attaching to the ventral margin of the base of the zygomatic process of the temporal bone and the caudal margin of the mandibular neck. The lateral ligament exhibited a greater constitution of dense irregular connective tissue, while the caudomedial and caudolateral ligaments showed a greater constitution of dense regular connective tissue. It is concluded that the TMJ of pigs presents one more ligament than horses, cattle, dogs, cats and what has been described for pigs themselves. We believe these results may contribute to the improvement of veterinary clinical and surgical therapy overall, as well as provide essential morphological information for a better interpretation and application of interspecies results in craniofacial research using pigs as an experimental model, as in the case of humans.

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.

Clinical profile in relation to age and gender of patients with temporomandibular disorders: a retrospective study

BACKGROUND

The present study is to evaluate the clinical characteristics of patients with temporomandibular disorders (TMD).

METHODS

A total of 3362 TMD patients were included. Each participant had complete medical records according to the diagnostic criteria for temporomandibular disorders (DC/TMD). The clinical characteristics including symptoms and signs in relation to age and gender were analyzed.

RESULTS

The mean age of the patients seeking care was 29.89 ± 13.73Y, and 68.6% of patients were aged 16-35 years. The female-to-male ratio of patients was 2.2: 1, and the average age of males was significantly lower than that of females. The prevalence of clicking symptoms decreased with age, while the prevalence of pain symptoms and limitations in jaw movement increased with age. Females were more likely to have limitations in jaw movement than males. Among the patients with pain, the average visual analogue scale (VAS) was 2.96 ± 1.23. The average VAS score of acute TMD patients (≤ 3 months) was significantly higher than that of chronic TMD patients (> 3 months).

CONCLUSIONS

The majority of TMD patients seeking care were young people. The number and average age of female patients was higher than the males. Female patients were more likely to have limitations in jaw movement than males.

Comparing microstructural and micromechanical deformation of the TMJ disc in two anterior disc displacement models

OBJECTIVE

Anterior disc displacement (ADD) has been used to establish temporomandibular joint disorder (TMD) models. Based on whether preserve of the retrodiscal attachment, the modelling methodologies include ADD with dissecting the retrodiscal attachment (ADDwd) and ADD without dissecting the retrodiscal attachment (ADDwod). This article aims to determine which model better matches the micromechanical and microstructural progression of TMD.

METHODS

Through meticulous microscopic observations, the microstructure and micromechanical deformation of the TMJ discs in ADDwd and ADDwod rabbit models were compared at 2 and 20 weeks.

RESULT

Scanning electron microscopy and transmission electron microscopy showed that collagen fibres became slenderized and straightened, collagen fibrils lost diameter and arrangement in the ADDwd group at 2 weeks. Meanwhile, nanoindentation and atomic electron microscopy showed that the micro- and nano- mechanical properties decreased dramatically. However, the ADDwod group exhibited no significant microstructure and micromechanical deformations at 2 weeks. Dissection of the retrodiscal attachment contribute in the acceleration of disease progression at the early stage, the devastating discal phenotype remained fundamentally the same within the two models at 20 weeks.

CONCLUSION

ADDwod models, induced stable and persistent disc deformation, therefore, can better match the progression of TMD. While ADDwd models can be considered for experiments which aim to obtain advanced phenotype in a short time.

Automatic detection and visualization of temporomandibular joint effusion with deep neural network

This study investigated the usefulness of deep learning-based automatic detection of temporomandibular joint (TMJ) effusion using magnetic resonance imaging (MRI) in patients with temporomandibular disorder and whether the diagnostic accuracy of the model improved when patients' clinical information was provided in addition to MRI images. The sagittal MR images of 2948 TMJs were collected from 1017 women and 457 men (mean age 37.19 ± 18.64 years). The TMJ effusion diagnostic performances of three convolutional neural networks (scratch, fine-tuning, and freeze schemes) were compared with those of human experts based on areas under the curve (AUCs) and diagnosis accuracies. The fine-tuning model with proton density (PD) images showed acceptable prediction performance (AUC = 0.7895), and the from-scratch (0.6193) and freeze (0.6149) models showed lower performances (p < 0.05). The fine-tuning model had excellent specificity compared to the human experts (87.25% vs. 58.17%). However, the human experts were superior in sensitivity (80.00% vs. 57.43%) (all p < 0.001). In gradient-weighted class activation mapping (Grad-CAM) visualizations, the fine-tuning scheme focused more on effusion than on other structures of the TMJ, and the sparsity was higher than that of the from-scratch scheme (82.40% vs. 49.83%, p < 0.05). The Grad-CAM visualizations agreed with the model learned through important features in the TMJ area, particularly around the articular disc. Two fine-tuning models on PD and T2-weighted images showed that the diagnostic performance did not improve compared with using PD alone (p < 0.05). Diverse AUCs were observed across each group when the patients were divided according to age (0.7083-0.8375) and sex (male:0.7576, female:0.7083). The prediction accuracy of the ensemble model was higher than that of the human experts when all the data were used (74.21% vs. 67.71%, p < 0.05). A deep neural network (DNN) was developed to process multimodal data, including MRI and patient clinical data. Analysis of four age groups with the DNN model showed that the 41-60 age group had the best performance (AUC = 0.8258). The fine-tuning model and DNN were optimal for judging TMJ effusion and may be used to prevent true negative cases and aid in human diagnostic performance. Assistive automated diagnostic methods have the potential to increase clinicians' diagnostic accuracy.

Corticosteroids for the Treatment of Internal Temporomandibular Joint Disorders: A Systematic Review and Network Meta-Analysis

Background: We evaluated the comparative effectiveness of all intra-articular injection corticosteroids for treating internal temporomandibular joint (TMJ) disorders. Methods: We searched MEDLINE, CENTRAL, EMBASE, SCOPUS, and LILACS through December 2023. We included randomized clinical trials (RCTs) enrolling patients with symptomatic internal disorders of the TMJ comparing any type of intra-articular corticosteroid therapy against another or to another minimally invasive therapy. The outcomes of interest were pain, range of mandibular motion (RoM), quality of life (QoL) and adverse effects at 1, 3, 6, and 12 months. We assessed the risk of bias using the Cochrane Collaboration's tool. We conducted a frequentist network meta-analysis and assessed the certainty of the evidence (CoE) using GRADE. Results: We included 20 RCTs enrolling 810 participants, which assessed five corticosteroids alone or combined with arthrocentesis or hyaluronic acid. Based on moderate CoE, betamethasone is among the most effective corticosteroids for reducing pain at one (mean difference compared to arthrocentesis [MD], -3.80; 95% confidence interval [CI], -4.55 to -3.05) and three months (MD, -2.74; 95%CI, -3.42 to -2.06), and arthrocentesis plus dexamethasone at six months (MD, -0.80; 95%CI, -1.57 to -0.03). There was no convincing evidence that any intervention was better than arthrocentesis for improving the RoM and QoL at any follow-up time. Methylprednisolone may be more harmful than arthrocentesis for adverse effects. Discussion: Betamethasone and arthrocentesis plus dexamethasone are the most effective in managing pain in the short and medium term compared to arthrocentesis (moderate CoE). Decisions about their use should consider other factors, such as costs, feasibility, and acceptability. Future research should consider QoL as an outcome and assess participants at longer follow-up periods.

Exploring the Association Between Gastroesophageal Reflux and Temporomandibular Joint Disorder in European Populations: A Bidirectional Mendelian Randomization Analysis

INTRODUCTION AND AIMS

Gastroesophageal reflux disease (GERD) and temporomandibular joint disorder (TMD) are relatively common conditions with a potential causal relationship. This study aims to investigate the possible causal relationship between GERD and TMD through bidirectional Mendelian randomization analysis.

METHODS

Using data from large GWAS databases, we conducted bidirectional Mendelian randomization analyses to investigate the potential causal link between GERD and TMD. Instrumental variables were selected from the IEU platform, comprising 129,080 GERD cases and 473,524 controls from the UK Biobank. TMD data from the FinnGen project included 6,314 cases and 222,498 controls.

RESULTS

The forward MR analysis suggested that GERD may increase the risk of TMD (OR = 1.47, 95% CI: 1.20-1.81, P = 2e-4). The Weighted Median method also yielded significant results (OR = 1.53, 95% CI: 1.14-2.04, P = 4.1e-3). However, the reverse MR analysis did not reveal a significant association between TMD and GERD (OR = 1.02, 95% CI: 0.98-1.05, P = .33).

CONCLUSION

This study, employing MR analysis, provides initial evidence supporting a potential causal relationship between GERD and TMD. The findings contribute to a better understanding of the relationship between these two conditions and offer insights for future clinical investigations.

CLINICAL RELEVANCE

The findings of this study hold potential clinical significance in guiding early management strategies for GERD, reducing the incidence of TMD, and optimizing healthcare resource allocation, thereby improving patient quality of life. Further clinical studies are warranted to validate these findings and explore underlying mechanisms.

Effect of occlusal contact on TMJ loading during occlusion: An in silico study

Alterations in occlusal features may have significant consequences, ranging from dental aesthetics to health issues. Temporomandibular joint disorders (TMDs) are often associated with joint overload, and the correlation between occlusal features and TMDs has been thoroughly discussed. In current work, we introduced a novel stomatognathic model that aligns well with in vivo experimental measurements, specifically designed to decouple the impact of occlusal contact and periodontal ligament (PDL) negative feedback on temporomandibular joint (TMJ) loading. Utilizing an in-silico approach, the simulation analysis included six symmetric occlusal contact scenarios. Furthermore, a biomechanical lever model was employed to clarify the mechanical mechanism and investigate the multi-factorial effects of TMJ overload. These findings indicate that anterior shifts in the occlusal centre lead to increased TMJ loading, particularly in occlusal contact cases with anteroposterior changes. Considering the symmetrical distribution of occlusal contact, mediolateral alterations had a more modest effect on TMJ loading. Additionally, potential negative feedback activated by principal strain of periodontal could not only alleviate joint load but also diminish occlusal force. These investigations enhance our understanding of the intricate interactions between masticatory muscles, occlusal forces, and joint contact forces, thereby providing motivation for future comprehensive studies on TMJ biomechanical overload.

Temporomandibular Joint Disorder: An integrated study of the pathophysiology, neural mechanisms, and therapeutic strategies

OBJECTIVE

The study aims to investigate Temporomandibular Joint Disorder (TMJD) through a interdisciplinary lens, integrating insights from neuroscience, dentistry, and psychology to dissect its complex pathophysiology and neural mechanisms. It focuses on exploring the neurobiological underpinnings of TMJD, emphasizing the role of pain perception, modulation, and the impact of neurophysiological changes on the disorder.

DESIGN

This is a comprehensive narrative review of the literature.

RESULTS

Research findings pinpoint altered pain perception and modulation processes as central neural mechanisms contributing to TMJD, highlighting the importance of personalized treatment approaches due to the disorder's complexity and patient variability. The study recognizes advances in neuroscience offering new treatment avenues, such as neuromodulation and biofeedback, which provide non-invasive and personalized options. However, it also addresses the challenges in TMJD research, such as the multifaceted nature of the disorder and the need for more comprehensive, interdisciplinary strategies in research and clinical practice.

CONCLUSIONS

TMJD is a multifaceted disorder requiring an interdisciplinary approach for effective management. The study stresses the crucial role of neuroscience in understanding and treating TMJD, facilitating the development of innovative treatment strategies. It emphasizes the need for further research, advocating an integrated approach that combines neuroscience, dentistry, and psychology to address TMJD's complexities comprehensively and improve patient care, thereby enhancing the quality of life for affected individuals.

Visual psychosocial profiling of Chinese temporomandibular disorder pain patients and correlations with somatosensory function

BACKGROUND

Psychosocial function of Chinese temporomandibular disorders (TMD) pain patients and the correlation with somatosensory function has not been sufficiently studied.

OBJECTIVE

The study aims at assessing the psychosocial function of Chinese TMD pain patients by visualisation method and evaluating the correlations with somatosensory function quantitatively.

METHODS

The Symptom Checklist 90 (SCL-90) questionnaire and standardised quantitative sensory testing (QST) were administered to 70 Chinese TMD pain patients and age- and gender-matched healthy controls (HCs). Of these, 40 TMD arthralgia patients received QST before and after medication. Psychosocial and somatosensory parameters were transformed into standardised scores. Differences within groups were assessed through t tests. Correlations between psychosocial and somatosensory profiles were explored through correlation analyses with Bonferroni correction for multiple comparisons.

RESULTS

100% of the Chinese TMD pain patients exhibited psychosocial distress in contrast to HCs. Anger and hostility showed negative correlation with the thermal nonnociceptive parameter (thermal sensory limen, p =.002) and nociceptive parameters (cold pain threshold and pain pressure threshold, p<.001). Correlation analysis indicated that cold detection threshold was negatively correlated with somatization and mechanical pain sensitivity had a negative correlation with anger and hostility through medical treatment (p <.001).

CONCLUSIONS

Visual psychosocial profiles provided an easy overview of psychosocial function in Chinese TMD pain patients. Anger and hostility was associated with increased thermal nonnociceptive and nociceptive sensitivity to stimuli. Psychosocial distress might be negatively associated with TMD treatment response which indicated a possible need for psychological intervention during treatment.

A regenerative approach for temporomandibular joint repair: An in vitro and ex vivo study

BACKGROUND

Current clinical approaches to regenerate temporomandibular joint (TMJ) articulating cartilage defects only treat the symptoms (i.e. pain and dysfunction) and do not seek to restore joint integrity for long-term relief. Therefore, we investigated a novel self-assembling tissue-engineered cartilage to overcome this significant clinical issue for TMJ regenerative purposes.

OBJECTIVES

Examine the maturation of dynamic self-regenerating cartilage (dSRC) using auricular chondrocytes and evaluate a novel combinatorial approach with fractional laser treatment and dSRC implantation for TMJ cartilage repair.

MATERIALS AND METHODS

A suspension of 107 freshly harvested rabbit ear chondrocytes was cultured under a continuous reciprocating motion to form the dSRC. After 2, 4 and 8 weeks of culture, dSRC samples were stained with H&E, Safranin-O and Toluidine Blue. Immunohistochemistry (IHC) was performed for collagens type I and II. Channels (300-500 μm diameter and 1.2-1.5 mm depth) were created in six freshly harvested condyles using a fractional Erbium laser. Two groups were tested: dSRC in a laser-ablated lesion (experimental) and an empty laser-ablated channel (control). TMJ condyles were cultured for up to 8 weeks and analysed as described above.

RESULTS

H&E staining showed a high cell density in dSRC compared to native cartilage. All dSRC groups demonstrated intense Safranin-O staining, indicating high glycosaminoglycan (GAG) production and intense Toluidine Blue staining showed high proteoglycan content. IHC confirmed that dSRC consisted predominantly of collagen type II. The experimental group showed improved cartilage repair at both time points compared to the empty channels.

CONCLUSION

dSRC viability and successful matrix formation were demonstrated in vitro. The combination of fractional laser ablation and dSRC implantation enhanced cartilage repair.

Cepstral Analysis of Voice in Patients With Temporomandibular Disorders

OBJECTIVES

This study aimed to assess the voice quality of patients with temporomandibular disorders (TMDs) compared with healthy subjects using cepstral analysis and investigate the relationship between the TMD severity and the values of cepstral analysis.

METHODS

Subjects who met the inclusion criteria completed a general health questionnaire and the Fonseca Anamnestic Index. Patients who had TMDs with FAI were subjected to an examination based on the Diagnostic Criteria for Temporomandibular Disorders. The final sample included 65 subjects, 31 TMDs patients (with a mean age ± standard deviation of 36.64 ± 13.67 years), and 34 healthy individuals in the control group (with a mean age ± standard deviation of 30.35 ± 7.78 years). Cepstral Peak Prominence (CPP) and Smoothened Cepstral Peak Prominence (CPPS) of a sustained vowel and connected speech were computed using Praat software.

RESULTS

TMD patients indicated lower cepstral values and lower voice quality compared to the control group. Significant differences were found between TMD and control groups for all cepstral parameters (P < .001) and cepstral measurements showed a moderate to strong negative correlation with TMD severity (P < .001, rho = -0.57 to -0.88).

CONCLUSION

The outcomes of the present study indicate that cepstral analysis can accurately distinguish the reduced voice quality of TMD patients from normal voice.

Evaluation of the efficacy and quality of life in patients with temporomandibular joint disorders treated with Kovacs digital occlusal splint: a pilot study

BACKGROUND

Few studies have been conducted on treating temporomandibular disorders (TMDs) with new digital occlusal splints, which has increasingly attracted wide attention.

METHODS

To evaluate the clinical efficacy and quality of life (QoL) of Kovacs digital occlusal splint (KDOS) treatment in patients with TMD.

MATERIALS AND METHODS

Eighty-nine patients with TMD who were treated using KDOS were analyzed. The patients were divided into three groups according to the Wilkes stage. The clinical symptoms and QoL scores of the patients in each group were recorded before and at least three months after treatment, and the data were statistically analyzed and compared. The relationships between the disease severity, sex, age, and level of QoL before treatment and improvement in the clinical symptoms were analyzed using binary logistic regression.

RESULTS

The mean age and follow-up period of the patients were 28.0 ± 10.4 years and 4.9 ± 2.1 months, respectively. After KDOS treatment, the improvement rates of joint noise and pain were 80.4% and 69.8%, respectively. Additionally, the patients' maximum mouth opening and global QoL mean scores significantly improved compared to those before treatment (p < 0.001). Binary logistic regression analysis revealed that the factors affecting the improvement in the clinical symptoms were disease severity and level of QoL before treatment.

CONCLUSIONS

KDOS can improve the clinical symptoms and QoL of patients with TMD. Moreover, patients without osteoarthritis and with low pretreatment QoL levels are more likely to demonstrate clinical improvement.

TRIAL REGISTRATION

The trial was registered with Chinese Clinical Trial Registry (ChiCTR) (ID: ChiCTR2300076518) on 11/10/2023.

Mechanisms Underlying Sex Differences in Temporomandibular Disorders and Their Comorbidity with Migraine

Sexual dimorphism in temporomandibular disorders (TMDs) and their comorbidity with migraine are important phenomena observed in clinics. TMDs are the most prevalent orofacial pain conditions with jaw joint and masseter muscle dysfunction. Migraine is the predominant headache commonly associated with TMDs. Women much more often suffer from this orofacial pain than men. However, currently, there is no gender-specific therapy for such pain conditions. Understanding the pathophysiological mechanisms behind sex differences in TMDs as well as their comorbidity with migraines is essential for developing novel approaches for gender-specific treatment of TMDs and related orofacial pain comorbidity. In this review, we summarize recent research progress regarding sex differences in TMDs, focusing on the underlying mechanisms including craniofacial anatomy, hormonal regulation, and roles of opioids, transient receptor potential channels, and endocannabinoid systems. We also discuss the mechanisms of comorbid TMDs and migraine. The information covered in this review will provide mechanistic insights into sex differences in TMDs and their comorbidity with migraine, which could aid in developing effective treatment strategies for the overlapping orofacial pain condition.

Proprioceptive neuromuscular facilitation stretching exercises for treatment of temporomandibular dysfunction in patients with forward head posture: A double-blinded, randomized, controlled trial

BACKGROUND

Proprioceptive neuromuscular facilitation (PNF) stretching exercises have been widely advocated for the management of patients with different musculoskeletal conditions. However, its effect on the treatment of temporomandibular dysfunction (TMD) in patients with forward head posture (FHP) has not been fully investigated.

OBJECTIVE

To investigate the effect of PNF stretching exercises on the treatment of TMD in patients with FHP.

METHODS

A prospective, randomized, double-blinded clinical trial. Twenty-four patients with TMD and FHP aged from 18-40 years were randomly assigned to PNF or control group. The PNF group composed of 12 patients received PNF stretching exercises of masticatory muscles in addition to routine physical therapy treatment (FHP correction exercises and ultrasound for the temporomandibular joint); the control group composed of 12 patients received routine physical therapy treatment only. Interventions were conducted twice a week for six weeks. Craniovertebral angle, pain threshold, pain intensity, temporomandibular joint ROM, and temporomandibular joint function were assessed for all participants before and after the intervention. The outcomes were analyzed using Two-way mixed MANOVA. For further multiple comparisons, post-hoc tests with the Bonferroni correction were performed.

RESULTS

There was no significant difference between both groups pre-treatment (p> 0.05). Comparison between groups post-treatment revealed statistically significant differences in all outcome measures (p< 0.05) in favor of the PNF group.

CONCLUSION

Adding PNF stretching exercises of masticatory muscles to routine physical therapy programs is an effective method for management of TMD in patients with FHP more than routine physical therapy programs alone.

The majority of patients report satisfaction more than 24 years after temporomandibular joint discectomy

PURPOSE

To retrospectively evaluate long-term outcomes after temporomandibular joint (TMJ) discectomy.

METHODS

Included patients (n = 64) had undergone discectomy during 1989-1998 at Umeå University Hospital. A questionnaire was used to evaluate pre- and postoperative symptoms, postoperative complications, general pain, and subjective opinion about the outcome of the surgery.

RESULTS

The results are based on responses from 47 patients (40 women/7 men), including 36 (30 women/6 men) who completed the questionnaire and 11 (10 women/1 man) who were contacted by telephone and answered selected questions. Seventeen patients were excluded because of death, a move abroad, declining to participate, or no available patient information. Among the respondents, 41 (87%) were satisfied with the results, five (11%) were unsatisfied, and one (2%) patient did not answer the question. The results showed a significant long-term improvement in locking, clicking/crepitation, and pain when chewing or opening the jaw (p = 0.001). The prevalence of headaches had decreased significantly at follow-up (p = 0.001). Reported impaired jaw-opening capacity showed no significant improvement (p = 0.08). Of the 47 respondents, 19 (40%) had asked for additional treatment after the discectomy, and six of the 19 patients (13%) had undergone more surgery of the joint.

CONCLUSION

The results of this retrospective long-term follow-up study indicate that TMJ discectomy has a high success rate, as most patients were satisfied with the postoperative results. Discectomy is thus an effective surgical intervention for patients with disabling TMJ pain and dysfunction when conservative interventions have been unsuccessful.

Muscle oxygenation and pain in different types of temporomandibular disorders

OBJECTIVES

Studies exploring variations in peripheral muscle oxygenation and pressure pain thresholds (PPT) of masticatory muscles in individuals with Temporomandibular Disorders (TMDs) are limited. The purpose of this study was to compare variations in peripheral oxygenation of the masseter muscle; PPT of the masseter and temporal muscles and correlate peripheral muscle oxygenation and PPT of the masseter muscle in individuals with different types of TMDs.

MATERIALS AND METHODS

Cross-sectional study involving 116 participants classified into three groups: muscle group (MG, n = 32), joint group (JG, n = 30) and muscle-joint group (MJG, n = 54). Individuals aged 26.97 ± 6.93, 68.97% female, 31,03% males were included. All participants were evaluated using the Diagnostic Criteria for Temporomandibular Disorders, Near-infrared spectroscopy (NIRS) for peripheral muscle oxygenation and pressure algometer for PPT.

RESULTS

There was no difference in masseter muscle oxygenation among groups. In the masseter muscle, a weakly positive correlation was observed between PPT and variation in tissue saturation index in the MG (rho = 0.365) and JG (rho = 0.317). In addition, the MJG expressed lower PPT (p = 0.004) than JG, demonstrating that MJG had more pain in this muscle.

CONCLUSIONS

MJG have lower PPT in the masseter muscle. Although the PPT is dependent on the type of TMDs, the correlation between PPT and oxygenation is weak. All TMDs groups evaluated (MG, JG, MJG) showed hemodynamic similarities of the masseter muscle.

CLINICAL RELEVANCE

Understanding pain thresholds and the hemodynamic behavior of the masticatory muscles contributes to a more assertive physiotherapeutic assessment in TMDs, serving as a basis for careful and individualized interventions.

The Gothenburg Trismus Questionnaire in China: Cross-cultural adaptation and measurement invariance

OBJECTIVES

The Gothenburg Trismus Questionnaire (GTQ) is a comprehensive scale for screening and assessing trismus in head and neck (H&N) cancer and temporomandibular joint disorders (TMD) patients. This study aimed to translate and cross-culturally adapt the GTQ in China, and to test its measurement invariance.

METHODS

This study comprised 278 H&N cancer, 245 TMD, and 507 control patients. Internal consistency and test-retest reliability were tested to assess the GTQ's reliability. The validity was evaluated through composite reliability (CR), average variance extracted (AVE), and correlation tests. Multi-group confirmatory factor analysis (CFA) was used to investigate the GTQ's measurement invariance across clinical status and gender. T tests were employed to compare score differences across clinical status and gender.

RESULTS

The Chinese version of GTQ scale shows excellent internal consistency and test-retest reliability. The CR, AVE, and correlation values demonstrate the good validity of GTQ. The multi-group CFA supported configural invariance across clinical status but not metric invariance, while it supported strict invariance across gender. Additionally, t tests revealed that patients with H&N cancer and TMD scored higher than the control group, while males scored higher than females.

CONCLUSIONS

The Chinese version of GTQ serves as an effective tool for screening and assessing trismus.

Quality of life and level of physical activity of individuals with temporomandibular disorders with and without otological symptoms: Secondary analysis of a cross-sectional study

BACKGROUND AND PURPOSE

Otological symptoms (OS) are highly prevalent in individuals with temporomandibular disorders (TMD). Individuals with TMD and OS have more neck disability and decreased deep neck muscles endurance when compared to individuals without OS. However, no studies have evaluated whether OS is associated with lower Quality of Life (QoL) and worse levels of physical activity. This study aimed to evaluate the QoL and level of physical activity of individuals with TMD with and without OS.

METHODS

In this cross-sectional study, 62 individuals with TMD were allocated into 2 groups: TMD with OS (n = 36) or TMD without OS (n = 26). Self-reported complaints of dizziness, vertigo, tinnitus, earache, ear fullness, or hypoacusis were considered as OS. QoL was assessed with the WHOQOL-Bref and physical activity with the IPAQ-SF. Independent t-test and chi-squared test were used for analysis between-groups. Effect sizes were reported using Cohen's d. A Pearson correlation was used to compare the number of OS and QoL scores. A significance level of p < 0.05% and 95% confidence intervals were considered statistically significant.

RESULTS

The total generic scores for QoL were not different between-groups (p = 0.076), but individuals with TMD with OS had lower satisfaction (p = 0.015; d: 0.63) and physical domain (p = 0.015; d: 0.64) scores with a moderate effect size. In TMD with OS, 69.4% of individuals were irregularly active and 50% for the TMD without OS, with no statistical significance (p > 0.05). The number of OSs was inversely and weakly associated with the QoL total score.

CONCLUSION

Individuals with TMD and OS are associated with worsened QoL (physical domain and satisfaction) when compared to individuals with TMD without OS. The higher the number of OS, the worse the QoL score. Individuals with TMD with and without OS had similar levels of physical activity, but a high prevalence of irregularly active and sedentary individuals within TMD diagnosed population was found.

Psychometric properties of the Indonesian Fonseca anamnestic index and the presence/severity of temporomandibular disorders among Indonesian young adults

OBJECTIVE

The psychometric properties of the Indonesian FAI (FAI-I) and presence/severity of temporomandibular disorders (TMDs) among Indonesian young adults were explored.

METHODS

The FAI-I was developed following the INfORM guidelines and used to determine the presence/severity of TMDs. Internal consistency/test-retest reliability were examined with Cronbach's alpha/intra-class correlation (ICC) coefficients. Construct/criteria validity were established by correlating (Spearman) the FAI-I to the five major TMD symptoms (5 Ts) and OHIP-14 (p < 0.05).

RESULTS

Five hundred-one participants (mean age 19.73 ± 1.27 years; 75.2% women) were recruited from a local University. Of these, 40.7% had no TMD, while 49.9%, 8.8%, and 0.6% had mild, moderate, and severe TMD. While Cronbach's α = 0.57 and ICC = 0.72, correlation coefficients to total 5 Ts and OHIP-14 were 0.53 and 0.47, respectively.

CONCLUSION

The FAI-I had low internal consistency, good test-retest reliability, and good validity. Moderate-to-severe TMD was experienced by 9.4% of the young adults examined.

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

AIM

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

SETTINGS AND DESIGN

Questinnaire study and review.

MATERIALS AND METHODS

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

STATISTICAL ANALYSIS USED

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

RESULTS

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

CONCLUSION

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

Neuroscience contributes to the understanding of the neurobiology of temporomandibular disorders associated with stress and anxiety

OBJECTIVE

This review proposes a neurobiological model for temporomandibular disorders (TMD) associated with stress and anxiety.

METHODS

An electronic search was performed in the PubMed, Embase, and Web of Science databases. Articles published up to 2020 were selected. The search terms were the following: temporomandibular disorders, anxiety, stress, neurobiology of stress and anxiety, and orofacial pain.

RESULTS

In total, there were 100 studies, which presented a total of 10 different analyses. The results were described, demonstrating the type of analysis that was performed on each item analyzed for a better understanding of the context.

CONCLUSION

The conclusion is that the interactions between the masticatory system, temporomandibular joints (TMJs), and stomatognathic apparatus with "stress neuromatrix," "pain neuromatrix," "limbic system," and "neuroimmunoendocrine system" would produce the range of changes observed in neural connectivity and the diversity of symptoms presented in 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.

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

ABSTRACT

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

Prevalence of temporomandibular disorders and their associated factors in Confucian heritage cultures: A systematic review and meta-analysis

BACKGROUND

Temporomandibular disorders (TMDs) may be an 'idiom' of psychological distress in Confucian heritage cultures (CHCs).

OBJECTIVES

This systematic review/meta-analysis estimated the prevalence of TMDs in CHCs and compared the differences in TMD occurrence between time periods and age groups. Additionally, the associated biopsychosocial risk factors were also examined.

METHODS

The study protocol was developed a priori following the PRISMA guidelines and Joanna Briggs Institute systematic review methodology (CRD42021245526). Electronic searches of seven databases were conducted from January 2002 to Dec 2021. Reference lists of identified studies were hand-searched for additional articles. Study selection, quality assessment, and data extraction were done. Meta-analysis was performed using the RevMan 5.4 software.

RESULTS

Forty-eight articles were included in the systematic review. Overall prevalences were: TMDs-15% (95% CI: 15-16%); TMD pain-8% (95% CI: 7-9%); TMJ sounds-24% (95% CI: 21-27%); and TMJ locking-7% (95% CI: 1-13%). While TMD prevalence appeared to have declined from 2002 to 2011 to 2012-2021, the occurrence of TMD pain, TMJ sounds, and locking increased marginally or remained constant. TMD prevalence in children/adolescents was 18% (95% CI: 14-22%) and 17% (95% CI: 16-18%) among adults. Significant associations between TMDs and bruxism/psychological distress/education levels were specified by 73%/90%/88% of the relevant studies.

CONCLUSIONS

TMDs are prevalent in CHCs and a slight increase in TMD pain (2%) and TMJ sounds (8%) were discerned over the past two decades. TMDs are related to a myriad of biopsychosocial variables, particularly psychological distress, and these factors must be addressed within the cultural context of patients.

The reports of specific waking-state oral behaviours, including awake bruxism activities, and psychological distress have a dose-response relationship: A retrospective medical record study

OBJECTIVE

To investigate if there are dose-response relationships between self-reported waking-state oral behaviours, including awake bruxism, and three indicators of psychological distress (depression, anxiety, stress).

METHODS

The study sample consisted of 1,886 patients with function-dependent TMD pain. Relationships between six non-functional and six functional waking-state oral behaviours, scored on a 5-point ordinal scale, and the psychological factors were investigated using ordinal logistic regression.

RESULTS

Mean age was 42.4 (±15.3) years, 78.7% being female. The odds of reporting the higher categories of non-functional oral behaviours depended on the severity of depression, anxiety, and stress. Most OR coefficients followed a quadratic dose-response distribution, the others increased linearly as the severity of the psychological scales increased. Almost no such associations were found with normal jaw function behaviours.

CONCLUSION

Within the limitations of this study, it may be concluded that non-functional waking-state oral behaviours, including awake bruxism, and psychological distress have a dose-response relationship, with higher levels of distress being associated with higher reports of oral behaviours.

Consensus Report and Recommendations on the Management of Late-stage Internal Derangement of the Temporomandibular Joint

Introduction: This report investigates late-stage internal derangement (ID) of the temporomandibular joint (TMJ) with the aim of establishing a more effective and personalized treatment protocol to improve patients' quality of life (QoL). Material and methods: A consensus was reached among maxillofacial surgeons specializing in LSID, based on a literature research and collective expert experience following the Delphi method. Consensus was considered to be achieved when a response received at least 80% of votes. Results: Four expert groups were established, respectively, focusing on diagnosis, minimally invasive surgery (MIS), open surgery and joint replacement. A comprehensive approach to late-stage ID of the TMJ requires a consensus report. This underscores the need for a personalized treatment plan, considering the variability in clinical presentations and progression of this pathology. Our recommendations aim to optimize clinical outcomes and enhance patient QoL.

Evaluation of the efficacy of pharmacological treatment in patients with temporomandibular joint dysfunctions using ultrasonography

STATEMENT OF PROBLEM

Temporomandibular joint dysfunctions (TMDs) are complex problems affecting the temporomandibular joints (TMJs), masticatory muscles, or both. TMDs are considered muscle pain caused by contraction and ischemia in the masticatory muscles, but evaluation of the efficacy of pharmacological treatment is lacking.

PURPOSE

The purpose of this clinical study was to evaluate the changes in masticatory muscles, joint space, and main arteries supplying the TMJs after pharmacological therapy in patients with TMDs using ultrasonography (USG).

MATERIAL AND METHODS

The TMJ space, masseter and temporal muscles, temporal superficial artery (TSA), and facial artery (FA) were examined using USG in 30 participants with acute TMD pain before and after 10 days of symptomatic treatment with analgesic and myorelaxant. The bilateral masseter and temporal muscle thicknesses, joint space, and end-diastolic minimum velocity (Ved), minimum end-diastolic minimum velocity (Vmin), peak systolic maximum velocity (Vmax), pulsatility index (PI), and resistance index (RI) values of the TSA and FA were measured and compared before and after pharmacological treatment. The relationship between the masseter muscle thickness and the Ved and Vmin values of the TSA and FA before and after pharmacological treatment was analyzed using the paired sample t test; the relationship between the temporal muscle thickness, TMJ spaces, and Vmax, PI, and RI values of the TSA and FA was analyzed using the Wilcoxon signed-rank test (α=.05).

RESULTS

A significant difference was found between the right temporal muscle thickness before and after medication (P=.01), whereas no statistically significant difference was found in the left temporal muscle thickness (P>.05). A significant difference was found between pretreatment and posttreatment bilateral masseter thicknesses at rest (right P=.014; left P=.004). No statistically significant difference was found in the bilateral joint space or Vmax, Vmin, Ved, PI, and RI values of the TSA and FA before and after treatment (P>.05).

CONCLUSIONS

Pharmacological treatment in participants with acute TMD led to a reduction in masseter and temporal muscle thickness but did not significantly affect joint space and local blood flow. USG is a useful diagnostic tool in the diagnosis and follow-up of TMDs.

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

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

The Challenges in Clinical Diagnosis of Trigeminal Neuralgia: A Review

The lack of established laboratory tests or biomarkers for trigeminal neuralgia (TN) makes diagnosing this relatively rare condition extremely challenging. Trigeminal nerve compression observable on magnetic resonance imaging may indicate TN, but many patients do not have visible lesions or compression. In particular, TN may be confused with migraine, cluster headache, temporomandibular disorder, and other types of headache. An accurate diagnosis is imperative for proper treatment since these conditions do not respond to the same treatment. Many symptoms of these headaches can be vague or overlap, and clinicians depend in large measure on the subjective reports of their patients. Nevertheless, it is imperative to diagnose TN better, which can cause excruciating pain, reduce the quality of life, and even result in disability. It is possible that TN is underestimated.

Prevalence and associations of temporomandibular disorders in older Brazilian adults

OBJECTIVE

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

BACKGROUND

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Skeletal Anterior Open Bite Attenuates the Chewing-Related Increase in Brain Blood Flow

The masticatory function of patients with skeletal anterior open bite (OPEN) is reported to be impaired compared with that of patients with normal occlusion (NORM). In this study, we compared brain blood flow (BBF) in patients with OPEN and NORM and investigated the factors related to BBF during mastication in patients with OPEN. The study included 17 individuals with NORM and 33 patients with OPEN. The following data were collected: number of occlusal contacts, jaw movement variables during mastication, and BBF measured with functional near-infrared spectroscopy during chewing. The number of occlusal contacts, maximum closing and opening speeds, closing angle, and vertical amplitude were smaller in the OPEN than in the NORM group. Interestingly, BBF increased less in the OPEN group. Correlation analysis revealed that several parameters, including number of occlusal contacts and closing angle, were correlated with changes in BBF during mastication. These results suggest that not only occlusion but also jaw movement variables and factors related to masticatory muscles contribute to the chewing-related increase in BBF. In conclusion, BBF increases less during mastication in patients with OPEN than in those with NORM. In addition, the higher increase in BBF is correlated with jaw movement. Together, we discovered that OPEN exhibits significant adverse effects not only on masticatory function but also on brain function.

Evaluation of the clinical performance of different occlusal device materials

STATEMENT OF PROBLEM

Computer aided technologies have been used to fabricate occlusal devices. However, the clinical behavior of the newly developed materials developed for occlusal devices is unknown.

PURPOSE

The purpose of this prospective, double-blind study was to assess the clinical efficacy of recently introduced computer-aided design and computer-aided manufacturing (CAD-CAM) materials for the fabrication of occlusal devices.

MATERIAL AND METHODS

A total of 24 participants were divided randomly into 2 study groups; polyetheretherketone (PEEK) and polymethyl methacrylate (PMMA), and a control group (CG). Conventional impressions and gypsum casts were obtained from all participants. In the study groups, the casts were digitalized with an extraoral digital scanner, designed with a software program (Bite Occlusal Device Module; exocad GmbH) and milled from PEEK and PMMA blocks. Clear resin sheets were used for occlusal device fabrication in the CG. The baseline measurements were made during the initial appointments. After 6 months, the participants returned for follow-up evaluations. Clinical performance based on surface roughness, wear of the antagonist teeth, occlusal device fit and therapeutic effect, as well as participant satisfaction were compared using the 1-way ANOVA test between the main groups (α=.05). The post hoc and Kruskal Wallis-H tests were used to compare the nonparametric group.

RESULTS

The therapeutic effects of the occlusal devices did not differ. All participants showed improvement in palpation and mandibular movement scores, but no statistically significant differences were found among the groups (P>.05). PEEK and PMMA had statistically less surface wear than CG (P<.001) and led to less antagonist tooth wear. No significant participant satisfaction difference was seen among the groups (P>.05). The control group had the best fit (P<.001).

CONCLUSIONS

Recent CAD-CAM materials exhibit clinically acceptable outcomes, and their performance is comparable with that of traditional materials. CAD-CAM materials appear suitable in terms of accuracy, surface wear, and therapeutic efficacy.

Voice quality in patients with temporomandibular disorders

OBJECTIVES

This study assessed the voice quality in TMD patients compared to healthy individuals using the Dysphonia Severity Index (DSI) and evaluated the correlation between the DSI and TMD severity.

METHODS

Patients who had TMD with Fonseca's anamnestic index were subjected to an examination based on the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). A sample of 35 patients with TMD and 36 healthy subjects were included in the study.

RESULTS

There were significant differences in the DSI score and its components between healthy subjects and TMD patients (p < .001). A significant correlation was found between the DSI scores and TMD severity (Spearman's rho: -0.90, p < .001).

CONCLUSION

Patients with TMD demonstrated lower DSI scores and lower voice quality compared to healthy subjects.

Temporomandibular Disorders, Bruxism and Headaches

Temporomandibular disorders (TMDs) and headache disorders are highly prevalent in the population. TMDs can present headache symptoms as a secondary headache and, in addition, be comorbid with primary headache disorders. This overlap has significant clinical implications for which it is essential for the physician to be aware, and they should screen for the potential presence of TMDs in a headache patient. Bruxism is a parafunctional behavior also prevalent in the population which has a role in TMDs and may influence headache symptomatology, but it is still necessary to clarify this relationship.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

OBJECTIVE

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

STUDY DESIGN

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

RESULTS

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

CONCLUSIONS

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

Accuracy of the Fonseca Anamnestic Index for identifying pain-related and/or intra-articular Temporomandibular Disorders

Objectives: This study established the diagnostic accuracy of the Fonseca Anamnestic Index (FAI) in relation to the Diagnostic Criteria for TMD (DC/TMD) standard.Methods: A total of 866 TMD patients and 57 TMD-free controls were instructed to answer the FAI and DC/TMD Symptom Questionnaire (SQ). Participants were subsequently categorized into no (NT), pain-related (PT), and/or intra-articular (IT) TMDs using the DC/TMD protocolized examination/algorithms. Receiver operating characteristics (ROC) curves, best cut-off points, and accuracy measures were determined.Results:The FAI demonstrated high accuracy for detecting all TMDs, PT, and IT (AUC = 0.96-0.98). The best cut-off points were 22.50 for all TMDs/IT and 27.50 for PT. Sensitivity of the FAI was high (94.23-98.21%), but specificity was moderate (87.72%) for all diagnostic categories.Discussion:The diagnostic accuracy of the FAI for identifying pain-related and intra-articular TMDs was high. FAI scores ≥25 points should be used to screen for TMDs.

Impact of the COVID-19 pandemic on clinical and psychological aspects of temporomandibular disorders

BACKGROUND

The Coronavirus 2019 disease (COVID-19) caused drastic changes in people's lifestyle that affected TMD characteristics through its physical and psychological influences. The aim of this study was to define the clinical and psychological characteristics of a large group of well-defined TMD patients and seek their differences between before and during the COVID-19 pandemic to establish points of care to be emphasized in the post-pandemic era.

METHODS

TMD patients diagnosed by the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) aged ≥ 18 were analyzed. Samples between September, 2017 to July, 2019 (n = 455) and March, 2021 to June, 2022 (n = 338) were collected to represent before and during COVID-19, respectively. The Graded Chronic Pain Scale (GCPS) and Symptom Checklist-90-Revision (SCL-90-R) were used to evaluate disability levels and psychological status. Clinical indices were compared between COVID periods and factors related to higher pain levels were investigated according to pandemic period.

RESULTS

More patients reported pain on palpation of the masticatory muscles during the pandemic (p = 0.021) while the number decreased for neck muscles (p = 0.001) and TMJ (p < 0.001) areas. Patients reporting nocturnal bruxism (23.3-29.6%) and clenching (45.1-54.7%) significantly increased during the pandemic. TMD patients with pain without disability were more common during the pandemic regardless of pain intensity (p < 0.001). The number of patients expressing interference in daily activities decreased drastically during COVID-19 regardless of disability level (p < 0.001). Factors associated with higher than moderate pain intensity (CPI ≥ 50) were insomnia (odds ratio [OR] = 1.603, p = 0.047) and somatization (OR = 1.082, p < 0.001) before the pandemic. During the pandemic, age (OR = 1.024, p = 0.007), somatization (OR = 1.070, p = 0.006), and paranoid ideation (OR = 1.117, p = 0.003) were significantly associated with higher pain intensity.

CONCLUSIONS

The results of our study underline the importance of evaluating psychological profiles of TMD patients, especially somatization, paranoid ideation and psychoticism, in exceptional situations that may cause a change in individual mental status. This will lead to a better understanding of the individual TMD patient and help in planning personalized treatment strategies that will assist the patient in adjusting to changes occurring in special environments such as the COVID-19 pandemic.

Brain alterations in sensorimotor and emotional regions associated with temporomandibular disorders

OBJECTIVES

Temporomandibular disorders (TMD) are characterized by sensorimotor and psychological dysfunction, with evidence revealing the implication of a dysfunctional central nervous system. Previous magnetic resonance imaging (MRI) studies have reported brain alterations in TMD, but most studies focused on either structure or function by a single modality of MRI and investigated static functional connectivity (FC) in TMD. By combining structural and functional MRI data, the present study aimed to identify brain regions with structural abnormalities in TMD patients and examine static and dynamic FC seeded by these regions to investigate structural brain alterations and related disrupted FC underlying the pathophysiology of TMD.

METHODS

We recruited 30 TMD patients and 20 healthy controls who underwent 3.0 T MRI scanning with T1-weighted images using a three-dimensional magnetization-prepared rapid gradient-echo sequence and resting state functional images using a gradient-echo echo-planar imaging sequence. Cortical thickness, volume, surface area, and subcortical volume were calculated, where brain areas with significant structural between-group differences were treated as seeds for static and dynamic FC analyses.

RESULTS

In this preliminary study, we found between-group alterations in sensorimotor regions including decreased cortical thickness in the right sensorimotor cortex as well as decreased volume in the left putamen and associated reduced dynamic FC with the anterior midcingulate cortex; and alterations in emotion processing and regulation regions including decreased volume/surface area in the left posterior superior temporal gyrus and associated increased dynamic FC with the precuneus in TMD patients than controls, having all p < 0.05 with corrections for multiple comparisons.

CONCLUSION

Our findings of structural and functional abnormalities in brain regions implicated in sensorimotor and emotional functions provided evidence for the biopsychosocial model of TMD and facilitated our understanding of the pathophysiological mechanism underlying TMD. The associations between neuroimaging results and clinical measurements of TMD warrant further exploration.

Changes in oral health-related quality of life after self-care treatment in patients with myofascial pain

OBJECTIVE

The aim of this study was to evaluate the changes in oral health-related quality of life (OHRQoL) of patients with myofascial pain treated by means of self-care measures.

METHODS

Fifteen patients with myofascial pain had OHRQoL evaluated by the Oral Health Impact Profile (OHIP-TMD) questionnaire and were instructed for self-care measures verbally and with a printed guide in the first consultation (T0), after 30 days (T1) and 60 days (T2). Paired t-test was performed to evaluate changes through time.

RESULTS

OHIP-TMD scores were 29.3 (SD 10.2) at T0, 18.9 (SD 11.2) at T1, and 15.9 (SD 10.7) at T2. There was a reduction of scores related to the OHIP-TMD domains of functional limitation, physical pain, psychological and social inability and incapacity (T1 and T2), and psychological discomfort (T2).

CONCLUSION

Self-care measures had positive effects on the myofascial pain treatment, reducing physical pain generated by TMD and improving patients' OHRQoL.

Severity and form of temporomandibular disorder symptoms: Functional, physical, and psychosocial impacts

OBJECTIVE

The associations between the presence of differing severity/form of temporomandibular disorder (TMD) symptoms and oral health-related quality of life (OHRQoL) were explored.

METHODS

The severity and form of TMDs in young adults were categorized based on the Fonseca Anamnestic Index (FAI) and Diagnostic Criteria for TMDs (DC/TMD), and OHRQoL was assessed with the Oral Health Impact Profile-14 (OHIP-14). Data were analyzed using non-parametric statistics (α = 0.05).

RESULTS

The study cohort consisted of 501 young adults (mean age 19.7 ± 1.3 years; 75.2% women). Participants with severe/moderate TMDs had significantly higher OHIP severity scores than those with mild/no TMDs. Moreover, participants with combined/pain-related symptoms exhibited significantly higher severity scores compared to those without symptoms. The physical pain and psychological discomfort domains were typically more impaired regardless of severity/form of TMD symptoms.

CONCLUSION

More severe and painful symptoms were related to greater impairments in OHRQoL, especially in the physical and psychological domains.

Biaxial Flexural Strength of Printed Splint Materials

One therapeutical alternative in the treatment of functional disorders is the use of printed oral splints. The mechanical properties of these materials are highly essential to their clinical effectiveness, and their performance may vary depending on factors such as cleaning, post-polymerization, or their orientation during construction. The objective of this in vitro investigation is to evaluate the effectiveness of the selected materials in terms of their biaxial flexural strength in relation to the criteria listed above. Splint materials were used in the printing of 720 discs. The printing process was carried out in different orientations in relation to the building platform. Either an automatic or manual cleaning process was performed on the samples. For post-polymerization, either an LED or Xenon light was utilized. A piston-on-three-ball test was used to measure the biaxial flexural strength (BFS) of the materials after they were stored in water for either 24 h or 60 days. The homogeneity of the data was controlled by employing the Levene method, and the differences between the groups were analyzed using the ANOVA and Bonferroni methods. After being stored for twenty-four hours, the mean BFS ranged anywhere from 79 MPa to 157 MPa. Following a period of sixty hours, the BFS exhibited a substantial drop and revealed values that ranged from 72 to 127 MPa. There was no significant difference that could be identified between the materials or between the various cleaning processes. The results of post-polymerization showed that the LED light produced higher means than the Xenon light did. In terms of position, the mean values varied greatly, with 0°'s mean value being 101 MPa, 45°'s mean value being 102 MPa, and 90°'s mean value being 115 MPa. The use of a build orientation of 90° and post-polymerization with LED light resulted in significantly increased biaxial flexural strength. According to this study, this design should be implemented in order to ensure that splint materials have the highest possible strength.

A Meta-Analysis of the Global Prevalence of Temporomandibular Disorders

Background: This meta-analysis aims to evaluate the proportion of people with TMDs in different studies, considering factors such as geographical region, patient age, and sample size. Methods: The search yielded 6984 articles on the incidence of TMDs. Finally, 74 studies with 172,239 subjects and 35,259 with TMDs were selected for final analysis. Analyses were performed using the R statistical language. Results: The incidence of TMDs in the world population was 34%. The age group 18-60 years is the most exposed to TMDs. From the data presented, we observed that for each continent, the female group was 9% to 56% larger than the male group. The highest female-to-male ratio (F:M) was reported in South America (1.56), whereas the lowest F:M ratio was reported in Europe (1.09), suggesting an almost equal distribution of males and females. Conclusions: This suggests that geographical location may play a role in the results of the studies. The prevalence of TMDs was significantly higher in South America (47%) compared to Asia (33%) and Europe (29%). Larger epidemiological studies of TMDs in African and Australian populations are recommended. In conclusion, both visual and statistical assessments suggest that the results of our meta-analysis are robust and unlikely to be significantly affected by publication bias. This suggests that geographical location may play a role in the prevalence of TMDs.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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