Temporomandibular joint disc displacement with reduction: a review of mechanisms and clinical presentation

Is there a superiority between arthrocentesis and stabilizing occlusal splint for the treatment of anterior disc displacement with reduction and intermittent block and anterior disc displacement without reduction in TMJ? Randomized clinical trial

INTRODUCTION

Anterior displacement of the temporomandibular joint (TMJ) disc is a disorder in which the articular disc is dislocated from its correct position relative to the mandibular condyle and mandibular fossa. Traditionally, the initial treatment of disc displacements involves various conservative measures, including the use of a stabilizing interocclusal splint. However, in cases where there is associated limited mouth opening, as in the case of anterior disc displacement with reduction and intermittent block (ADDwRIB), and anterior disc displacement without reduction (ADDw/oR), arthrocentesis has been suggested as another modality of initial treatment due to its faster effect in preventing disease progression to a more advanced stage, as well as reducing the chances of pain chronification and central sensitization.

OBJECTIVES

This study aimed to analyze whether there is a preponderance in efficacy between treatments with a stabilizing interocclusal splint or arthrocentesis in these patients.

METHODS

A randomized, prospective, longitudinal clinical trial was conducted. The sample was obtained by convenience, between June 2021 and January 2023. Twenty-four patients with diagnoses of ADDwRIB and ADDw/oR were included. The diagnosis and clinical evaluations followed the DC/TMD criteria, and TMJ MRI was performed. Patients were randomly allocated to 2 treatment groups. Group 1 (n = 13): stabilizing interocclusal splint. Group 2 (n = 11): arthrocentesis. Patients were evaluated after 1, 2, 3, and 6 months for clinical parameters of pain, functionality, and psychosocial status.

RESULTS

Both treatments were effective in reducing pain levels, with no statistically significant differences. Group 1 showed significantly greater mouth-opening levels compared to Group 2 (P = .041).

CONCLUSION

Both groups showed significant improvements in various parameters evaluated throughout the study, indicating they are equally effective in pain control and most functional and quality of life parameters. However, the stabilizing interocclusal splint treatment was superior in restoring mouth opening.

Ultrasound-Guided Vs Non-Guided Prolotherapy for Internal Derangement of Temporomandibular Joint. A Randomized Clinical Trial

OBJECTIVES

This randomized clinical trial study aims to compare ultrasound-guided versus non-guided Dextrose 10% injections in patients suffering from internal derangement in the temporomandibular joint (TMJ).

MATERIAL AND METHODS

The study population included 22 patients and 43 TMJs suffering from unilateral or bilateral TMJ painful clicking, magnetic resonance imaging (MRI) proved disc displacement with reduction (DDWR), refractory to or failed conservative treatment. The patients were divided randomly into two groups (non-guided and ultrasound (US)-guided groups). The procedure involved injection of 2 mL solution of a mixture of 0.75 mL 0.9% normal saline solution, 0.3 mL 2% lidocaine and 0.75 mL dextrose 10% using a 25G needle in the joint and 1 mL intramuscular injection to the masseter muscle at the most tender point. The Visual Analogue Score (VAS) was used to compare joint pain intensity over four different periods, beginning with pre-injection, 1-, 2-, and 6-months postinjection.

RESULTS

Twenty-two patients 5 males (n = 5/22, 22.7%) and 17 females (n = 17/22, 77.2%) were included in this study. The mean age was 27.3 ± 7.4 years (30.2 ± 7.0) for the non-guided group and 24.3 ± 6.9 for the US-guided group. The dextrose injection reduced intensity over time in both groups with statistically significant improvement (P value <.05) at 2 and 6 months in both groups. There was no statistically significant difference in VAS assessment between both groups.

CONCLUSION

Intra-articular injection of dextrose 10% for patients with painful clicking and DDWR resulted in reduced pain intensity in both US-guided and non-guided groups with significant symptomatic improvement over time in both groups. US guidance allowed accurate anatomical localization and safe procedure with a single joint puncture.

Evidence or else: Concerning trends and the legal risks of unsubstantiated orthodontic-surgical practices

BACKGROUND

Over the past decade, orthodontics has advanced markedly with digital methods, cutting-edge biomechanics, and 3-dimensional diagnostics. However, the rapid adoption of these innovations without rigorous evaluation of their evidential support has led to new unsubstantiated orthodontic-surgical indications.

METHODS

This article explores emerging orthodontic practices, focusing on the interpretation of orthodontic principles and the reliance on imaging-based diagnoses.

RESULTS

Strict adherence to mechanistic orthodontic principles and reliance on imaging findings can result in overzealous treatment protocols. It also emphasizes the state of knowledge regarding temporomandibular disorders (TMDs) and the lack of consensus and evidence-based guidelines.

CONCLUSIONS

There is an urgent need for the profession to integrate TMD knowledge, adopt evidence-based practices, and critically evaluate new methods before implementation.

PRACTICAL IMPLICATIONS

Orthodontists should move away from outdated mechanistic beliefs and integrate clinical knowledge from TMD research into their practices. Increased awareness and potential legal repercussions may drive a necessary reevaluation and stronger adherence to evidence-based methods.

Exploring the effect of disc displacement on the risk and severity of condylar erosion in adult temporomandibular disorder patients: A CBCT and MRI study

OBJECTIVE

The objective of the study was to investigate the relationship between types of disc displacement (DD) diagnosed by magnetic resonance imaging (MRI), and the risk (presence or absence) and severity of condylar erosion (CE) graded using cone-beam computed tomography (CBCT) in adult Temporomandibular disorders (TMD) patients.

METHODS

A total of 353 TMD patients (283 females, 70 males) underwent MRI scans to categorise DD as normal (NA), anterior displacement with reduction (ADDR), or anterior displacement without reduction (ADDNR). CE severity was graded on a scale of 0-3 (absence, mild, moderate or severe) using CBCT. To establish the plausibility and cut-off points for CE diagnosis, the severity of CE was then further divided into three classifications: Grade 0 versus 1 + 2 + 3; Grades 0 + 1 versus 2 + 3; Grades 0 + 1 + 2 versus 3. Logistic regression analysis was performed, adjusting for age, gender and joint correlation.

RESULTS

ADDNR significantly increased the risk of CE compared with NA (OR = 10.04, 95% CI: [6.41, 15.73]) and showed a significant increase in CE severity across all classifications (ORs = 10.04-18.95). The effects of ADDNR were significant in both genders (p < .001) and had a greater impact in females. ADDR was predominantly associated with mild CE.

CONCLUSIONS

ADDNR significantly increased the risk and severity of CE independent of gender when compared to NA, whereas ADDR was mainly associated with mild CE. Slight cortical discontinuity may represent a subclinical diagnosis requiring further investigation.

Synthesis of temporomandibular disorders management intervention outcomes for development of core outcome sets: A systematic review

INTRODUCTION

The selection of appropriate outcomes in clinical trials and systematic reviews is a crucial factor in determining the results that are useful, reliable, and relevant for both patients and healthcare professionals. Clinicians and researchers have been encouraged to develop and apply core outcome sets (COS) to minimise the discrepancy between studies.

AIM

This systematic review is the first phase of the COS development project for clinical trials in temporomandibular disorders (COS-TMD). It aims to identify and synthesise the outcomes used in the randomised controlled trials (RCT) that evaluated the effectiveness of interventions used in TMD management.

MATERIALS AND METHODS

An electronic search was performed in several databases: MEDLINE (via PubMed), Scopus, Web of Science, Cochrane Library and EMBASE. The eligibility criteria comprised RCT that applied any intervention to treat temporomandibular joint disorders or masticatory muscle disorders. The identified outcomes were categorised according to domains of the Initiative on Methods, Measurement and Pain Assessment in Clinical Trials (IMMPACT).

RESULTS

The electronic search resulted in 1606 studies. After removing duplicates and applying the eligibility criteria, 106 RCT were included. A total of 43 studies evaluated masticatory muscle disorders, 27 evaluated temporomandibular joint disorders, and 36 analysed mixed TMD.

CONCLUSIONS

The evaluation showed significant variability in the types of outcomes and their measurement instruments. In addition, some domains such as physical and emotional functioning, participant ratings of global improvement and adverse events have been neglected when determining the effectiveness of treatments for 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.

Comparative study of arthrocentesis with concentric-needle cannula with classic concentric needle: A randomized single-blind controlled clinical trial

This study aimed to assess and compare the efficacy of two distinct single-puncture techniques in temporomandibular joint (TMJ) arthrocentesis for managing disk displacement without reduction (DDwoR). Sixty patients with DDwoR were randomly and blindly assigned to two treatment groups (n = 30 each): group 1 - TMJ arthrocentesis with the classic concentric needle; and group 2 - TMJ arthrocentesis with the concentric needle-cannula system. The following variables were recorded and compared across the groups: patient's pain perception (visual analog scale - VAS, 0-10); maximal interincisal distance (MID, mm); facial edema (FE, presence or absence); and operation duration (OP, minutes). Patients in group 2 presented significantly lower values of VAS score and presence of FE (p < 0.05) when examining the data at 24 and 48 h after the arthrocentesis. They also showed an increase in MID values (p = 0.024) after 6 months. With regard to OP, no significant difference was observed between the groups. Performing a single-puncture TMJ arthrocentesis using a concentric needle-cannula system significantly reduced the patients' pain perception, and mitigated the presence of facial edema during the immediate postoperative period (at 24 and 48 h). Furthermore, it resulted in a notable increase in the MID after 6 months.

Does Piroxicam have an Added Benefit on Arthrocentesis in the Management of Internal Derangement in Female Patients?: A Randomized Clinical Trial

BACKGROUND

Arthrocentesis is an accepted treatment modality for internal derangement. Piroxicam is an NSAID that can be injected into the TMJ.

PURPOSE

The primary objective of this study was to improve mouth opening, and the secondary objective was to decrease TMD-associated pain.

METHODS

A randomized controlled trial (RCT) was performed on patients suffering from anterior disk displacement with reduction. Patients were divided into 2 groups: a study in which patients underwent arthrocentesis followed by an injection of 20 mg of piroxicam. Independent and paired sample t-tests were used to assess mouth opening. The χ2 test was used to assess the pain data; the P value was fixed at 0.05.

RESULTS

Twenty female patients were included in the current study. To ensure that covariables did not affect the study results, an intergroup assessment using Student's t-test for unassisted mouth opening without pain preoperatively showed that the maximum unassisted opening without pain was 20.8±3.9 mm in the control group, and the average maximum unassisted opening without pain was 19.7±1.1 mm in the case study group. The unassisted mouth opening in the control group was 30.9±3.4 mm and 31.8±3.6 mm, respectively, and there was no significant difference (P=0.6, 95% CI: -2.5 to 4.32). There was no significant difference in pain between the study and control groups (P=0.3).

CONCLUSION AND RECOMMENDATION

Based on the results of the present study, arthrocentesis using piroxicam does not have any benefit over conventional arthrocentesis.

Surgical treatment of intracapsular temporomandibular disorders

OBJECTIVE

Temporomandibular joint (TMJ) pathologies are prevalent, affecting approximately 40% of the worldwide population, with nearly 80% involving intracapsular disorders. Despite this, standardized treatment protocols are lacking. This study aimed to compare the efficacy of conservative and surgical approaches in managing intracapsular TMJ disorders.

METHODS

Eighty-six patients diagnosed with intracapsular TMJ disorders were included in the study, with 40 males and 46 females, averaging 52.4 ± 4.7 years. Patients were recruited from polyclinics in Beijing, China (n = 36), and Kyiv, Ukraine (n = 50). A comprehensive examination protocol was conducted, including assessment of patient complaints, medical history, jaw mobility measurements, TMJ palpation, and magnetic resonance imaging (MRI) screening.

RESULTS

The main outcomes of our study revealed significant improvements in patients undergoing surgical intervention for intracapsular TMJ disorders, particularly in cases of disc displacement. Conservative mouth guard/occlusal splint treatment showed limited effectiveness, primarily improving joint effusion and disc displacement. Surgical intervention led to notable enhancements in various TMJ parameters, with significant improvements observed in joint function and pain reduction. Based on these findings, orthodontic rehabilitation was recommended to ensure long-term efficacy, focusing on optimizing occlusion and restoring TMJ function. These results highlight the importance of tailored treatment approaches for managing intracapsular TMJ disorders, emphasizing the role of surgical intervention coupled with comprehensive rehabilitation strategies.

CONCLUSIONS

Future research should consider demographic factors and explore innovative examination methods, such as optical systems, to enhance understanding and management of intracapsular TMJ disorders.

Clinical effect of digitalized designed and 3D-printed repositioning splints in the treatment of anterior displacement of temporomandibular joint disc

OBJECTIVE

To compare the treatment effectiveness of digitized and 3D-printed repositioning splints with that of conventional repositioning splints in the treatment of anterior displacement of the temporomandibular joint disc.

METHODS

This retrospective study included 96 patients with disc displacement of the anterior temporomandibular joint. They were treated with either digitally designed and 3D-printed repositioning splints or traditional splints and followed up for at least six months. Changes in signs and symptoms such as pain and mouth opening before and after treatment were recorded to evaluate treatment outcomes.

RESULTS

During the first month of treatment, both the digitally designed and 3D-printed repositioning splint groups (Group B) and the traditional repositioning splint group (Group A) showed significant increases in mouth opening, with increases of 4.93 ± 3.06 mm and 4.07 ± 4.69 mm, respectively, and there was no significant difference between the two groups. Both groups had a significant reduction in visual analog scale (VAS) pain scores, with Group B showing a greater reduction of 1.946 ± 1.113 compared to 1.488 ± 0.978 in Group A (P < 0.05). By the sixth month, Group B's mouth opening further improved to 38.65 ± 3.22 mm (P < 0.05), while Group A's mouth opening did not significantly improve. Regarding pain, Group A's VAS score decreased by 0.463 ± 0.778 after one month, and Group B's score decreased by 0.455 ± 0.715; both groups showed significant reductions, but there was no significant difference between the two groups.

CONCLUSION

Compared with traditional repositioning splints, digitally designed and 3D-printed repositioning splints are more effective at reducing patient pain and improving mouth opening. 3D-printed repositioning splints are an effective treatment method for temporomandibular joint disc displacement and have significant potential for widespread clinical application.

Temporomandibular disorder symptoms, sleep quality, and burnout syndrome in teachers

OBJECTIVE

The aim of this study was to assess the association between the symptoms of temporomandibular disorder (TMD), sleep quality, and indicators of burnout syndrome in teachers.

METHODS

This cross-sectional study included 330 teachers with an average age of 43 years. The Diagnostic Criteria for Temporomandibular Disorders, Pittsburgh Sleep Quality Index, and the questionnaire to assess burnout syndrome - teachers' version were used for data collection. Simple and multiple logistic regression models were applied to analyze the independent variables at a 5% significance level.

RESULTS

Teachers with poor sleep quality, indicators of burnout syndrome, female sex, and impact on the domains of psychological exhaustion and guilt were, respectively, 1.91,1.92, 2.66, 1.97, and 2.60 times more likely to present at least one TMD symptom (p < 0.05).

CONCLUSION

Teachers with indicators of burnout syndrome and impaired sleep quality were more likely to present with at least one TMD symptom.

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.

The biomechanical effects of bimaxillary osteotomies to the patients with mandibular retraction under incisal clenching

The purpose of this study is to investigate the biomechanical effect of bimaxillary osteotomies on patients with mandibular retraction. Mandibular retraction, as a typical maxillofacial deformity, and has great adverse effects on TMJ. Bimaxillary osteotomies are widely used to correct symptoms of mandibular retraction. It is necessary to understand the effect of surgery on temporomandibular disc (TMJ). Five patients with mandibular retraction and 10 asymptomatic subjects were involved in this study. Finite element models of preoperative, postoperative and control group were constructed based on the CT data. Nine sets of concentrated forces were used to simulate the muscle effect and contact method was used to simulate the interaction within the TMJs and dentitions. The results showed that bimaxillary osteotomies could effectively improve the maxillofacial morphology and alleviate the overload in TMJ. The facial asymmetry and right chewing side preference could cause imbalanced stress distributions in the TMJs and interfere the surgical treatment.

Mental health and jaw function of patients with anterior disc displacement with reduction

BACKGROUND

The mental health of patients with temporomandibular disorder or other jaw dysfunction is a primary concern in clinical practice, but the extent of these symptoms in this patient subset is not yet well understood.

OBJECTIVES

This cross-sectional study aimed to compare the mental health and jaw function between patients with anterior disc displacement with reduction (ADDWR) and healthy individuals.

METHODS

In total, 170 patients with ADDWR and 163 healthy participants enrolled in this study from March 2020 to December 2021. All participants completed a single assessment, including a pain rating and several questionnaires to assess jaw dysfunction, depression, and anxiety. All scores and the grade distribution of somatization, depression and anxiety were analysed between groups.

RESULTS

Significant differences were found in measures of pain, jaw function and somatization; the ADDWR group had significantly higher pain and functional jaw limitations than the healthy group. The grade distribution of somatic symptoms also differed between groups: the distribution of patients who reported mild and above scores in the ADDWR group was significantly higher than that of the healthy group. Depression and anxiety scores or grade distributions were not significantly different by group.

CONCLUSION

The jaw function of patients seeking treatment for ADDWR was lower than that of non-TMD individuals. They did not show high anxiety and depression symptoms, but their somatic symptoms were more apparent.

The benefits of performing temporomandibular joint arthrocentesis with catheters and a vacuum pump: A randomized control trial

This study aims to compare the effectiveness of two different techniques of double puncture arthrocentesis with and without the addition of catheters and a vacuum pump for management of temporomandibular joint (TMJ) disc displacement without reduction (DDWOR). A total of 48 patients with DDWOR were randomly and blindly allocated into two treatment groups (N = 24): Group 1, TMJ arthrocentesis with the addition of catheters and a vacuum pump to the second needle; Group 2, TMJ arthrocentesis without any addition device. The following variables were registered and compared between groups: patient's pain perception (visual analogue scale [VAS; 0-10]); maximal interincisal distance [MID; mm]; joint effusion (JE, presence or absence); facial edema (FE; presence or absence); and the operation duration (OP; minutes). Patients in Group 1 presented with significantly lower VAS scores (p < 0.001) and presence of FE (p = 0.03) in the post-operative period, also an increase in MID values (p = 0.026), and a reduction in JE (p = 0.022) after 3 months. Besides that, in this group, the procedure was performed significantly faster (p < 0.001). Performing arthrocentesis with the addition of a vacuum pump makes the procedure faster and yields better results in terms of pain, facial swelling, mouth opening and joint effusion.

Correlation between craniocervical posture and upper airway dimension in patients with bilateral anterior disc displacement

OBJECTIVE

To investigate the relationship between upper airway dimension and craniocervical posture in adult patients with bilateral anterior disc displacement and to provide some references for clinical diagnosis and plan formulation in orthodontics.

METHODS

Based on RDC/TMD (Research Diagnostic Criteria for Temporomandibular Disorder), 98 Patients were divided into three groups by two experienced TMJ (Temporomandibular Joint) specialists: bilateral disc normal position group (BN), bilateral anterior disc displacement with reduction group (ADDWR) and bilateral anterior disc displacement without reduction group (ADDWoR). Inter-group comparison and correlation analysis were performed after 11 craniocervical posture and 15 upper airway dimension measurements finished with Dolphin and Uceph software in Two or Three-dimensional.

RESULTS

Anterior disc displacement often accompanied with extension of craniocervical posture, as ADDWR and ADDWoR groups have significantly higher cervical curvature and inclination than BN group (P < 0.05). Simultaneously anterior disc displacement often associated with constrained upper airway dimension for the total and each segment upper airway volume were significantly smaller in ADDWR and ADDWoR than BN group (P < 0.05). Correlation analysis revealed that C0-C1 (the distance from the base of the occipital bone (C0) to the posterior arch of the atlas (C1)) is significantly related to the total and each segment upper airway volume reduction (P < 0.05).

CONCLUSION

There exists markedly close correlation between anterior disc displacement and craniocervical posture forward extension, which may be physiologically adaptive cervical extension to keep oropharyngeal airway unobstructed as upper airway dimension constrained by anterior disc displacement.

CLINICAL RELEVANCE

These findings allow us to infer the potential consequences if the treatment of anterior disc displacement would result in an improvement of intervertebral relationships and upper airway constraint.

The Relationship between Kinesiophobia, Emotional State, Functional State and Chronic Pain in Subjects with/without Temporomandibular Disorders

Although there is growing evidence that kinesiophobia is correlated with temporomandibular disorders (TMD), its relationship with other characteristic TMD comorbidities, such as depression, anxiety, functional limitations, and pain in the TMD population, has rarely been investigated. This study aims to evaluate the relationship between kinesiophobia, emotional state, functional state and chronic pain in subjects both with and without TMD. A total of 94 subjects participated in the study and were divided into two groups (47 subjects each)-TMD (subjects with temporomandibular disorders) and nTMD (asymptomatic controls)-on the basis of the RDC/TMD protocol. All measurements were taken with self-administered questionnaires: TSK-TMD for kinesiophobia, PHQ-9 and GAD-7 for psychoemotional state, JFLS-20 for jaw functional limitations, and GCPS for chronic pain. The prevalence of kinesiophobia in the TMD group was 38.3% for moderate risk, and 61.7% for high risk. The TMD group showed significantly higher scores in all categories (kinesiophobia, depression, jaw functional limitations and chronic pain), with the exception of anxiety which was right at the cut-off point. Moreover, a significant correlation was found between kinesiophobia (TSK-TMD) and jaw functional limitations (JFLS-20). Results of this study could provide new insight into the relationship between kinesiophobia and TMD, further improving the diagnosis process.

The biomechanical effects of bilateral sagittal split ramus osteotomy and bimaxillary osteotomies to the patients with maxillofacial deformities under incisal clenching

OBJECTIVE

Bilateral sagittal split ramus osteotomy (BSSRO) and bimaxillary osteotomies (BSSRO plus Lefort1 osteotomy) are widely used to solve maxillofacial deformities. The effect of the surgeries on the temporomandibular joint (TMJ) is still not clear. The purpose of this study was to investigate the preoperative and postoperative stress environment of the patients and to compare the biomechanical differences of the two surgeries.

METHODS

Ten patients were performed BSSRO and fourteen underwent bimaxillary osteotomies. Eleven asymptomatic subjects were recruited to be the control group. The muscle forces of incisal clenching were applied on the finite element models. And contact was used to simulate the interactions within the TMJs.

RESULTS

two kinds of surgeries could not completely eliminate the negative biomechanical distribution within the TMJs.

CONCLUSION

Compared to BSSRO only, the bimaxillary osteotomies could better repair the biomechanical environment of the TMJs under incisal clenching. And the TMD symptoms were strongly related to the stress distributions of the TMJs.

Correlation between temporomandibular joints and craniocervical posture in patients with bilateral anterial disc displacement

OBJECTIVE

To study the changes of temporomandibular joints and craniocervical posture in adult patients with bilateral anterior disc displacement, and to explore their correlation, which may provide some clinical value for clinical diagnosis and treatment planning.

METHODS

Ninety-eight adult patients were divided into 3 groups: 29 patients in bilateral disc normal position group (BN), 33 patients in bilateral Anterior Disc Displacement With Reduction group (ADDWR) and 36 patients in bilateral Anterior Disc Displacement Without Reduction group (ADDWoR). Dolphin and Uceph software were used to measure 14 items of temporomandibular joint and 11 items of craniocervical posture for comparison and correlation analysis between groups.

RESULTS

There were significant differences in bilateral joint space between three groups. Compared with the BN, the anteroposterior diameter of the condyle was significantly reduced, the condyle was significantly displaced posteriorly and superiorly in the ADDWR and ADDWoR, but the joint fossa width and joint fossa depth did not change significantly. Cervical curvature and inclination were greater in patients with anterior disc displacement than BN, indicating that the craniocervical posture of adult patients with anterior disc displacement was extended and protrusive.

CONCLUSION

Anterior disc displacement of the temporomandibular joint can displace the condyle upwards and posteriorly and reduce the anteroposterior diameter of condyle, and then make the condyle closer to the wall of articular fossa to induce joint symptoms. Additionally, craniocervical postural position is significantly affected, which may be related to compensate for the effects of airway space.

Morphological analysis of the temporomandibular joint in patients with anterior disc displacement

This study aims to investigate the morphological characteristics of the temporomandibular joint (TMJ) in the patients with anterior disc displacement with reduction (ADDwR) and the alterations after occlusal splint treatment. Thirty ADDwR patients and ten asymptomatic subjects were recruited. Thirteen parameters were adopted, along with automatic computation and presentation of the joint space to characterize the TMJ morphologies. Statistical results showed that morphological discrepancies between the patients and the asymptomatic subjects were ubiquitous. The adjustment of condyle position through occlusal splint treatment can result in joint spaces widening and has positive effects on mitigating the conditions of ADDwR.

Assessment of temporomandibular joint bone changes associated with anterior disc displacement: An MRI cross-sectional study

OBJECTIVE

This cross-sectional study aimed to evaluate the presence of bone changes on magnetic resonance imaging (MRI) scans of patients with temporomandibular joint (TMJ) anterior disc displacement (ADD) with reduction (ADDWR) and without reduction (ADDWoR).

METHODS

TMJ-MRI scans were screened for the presence of ADD. 285 scans presented ADD, being further divided into ADDWR (n = 188) and ADDWoR (n = 97). Bone changes on the mandibular condyle and articular eminence were also assessed and computed. The chi-square test compared the association of these bone changes with the presence of ADDWR and ADDWoR, with a significance level of 5 %. Also, the prevalence ratio (PR) was calculated.

RESULTS

In the mandibular condyle, subchondral cyst (p = 0.035, PR = 1.08) and bone edema (p = 0.044, PR = 2.40), more prevalent on ADDWR, and generalized sclerosis (p = 0.015, PR = 1.04), more prevalent on ADDWoR, presented significant association with ADD. On the articular eminence, generalized sclerosis (p = 0.015, PR = 1.04) and articular surface flattening (p = 0.003, PR = 1.19) presented significant association with ADD, both more prevalent on ADDWoR.

CONCLUSION

Bone changes are usual findings in TMJ with ADD diagnosis. The real influence of ADD is not fully clear, although clinicians should be aware of patients with this condition, to provide an early diagnosis and improve patient´s prognosis.

An Update on Temporomandibular Disorders (TMDs) and Headache

PURPOSE OF REVIEW

To provide an overview and highlight recent updates in temporomandibular disorders (TMDs) and their comorbidity with headache disorders regarding pathophysiology and management.

RECENT FINDINGS

In the last decade, there have been great advancements in the understanding of TMDs and their relationship with neurovascular pains such as headaches. Understanding of TMDs is necessary for the context of its comorbidity with primary headache disorders. The literature regarding management of these comorbidities is scarce but points to combination therapy including pharmacological and non-pharmacological approaches to optimize management. The use of CGRP receptor-targeted monoclonal antibodies or CGRP receptor antagonists should be explored for the management of chronic TMDs. It could also be used as a novel monotherapy or in combination with non-pharmacological approaches for TMDs' comorbidity with headache, particularly migraine. Research is needed to support evidence-based management protocols. A team involving neurology (headache medicine) and dentistry (orofacial pain) is critical for optimal management.

Clinical study of magnetic resonance imaging-based texture analysis and fasciculation of the lateral pterygoid muscle in young patients with temporomandibular disorder

OBJECTIVE

We aimed to evaluate the effectiveness of clinical examination combined with texture analysis of magnetic resonance imaging (MRI) and fasciculation patterns of the lateral pterygoid muscle (LPM) in distinguishing among the different anatomic causes of temporomandibular disorder.

METHODS

We divided the patients into four groups: healthy control (HC), disk without displacement (DWoD), disk displacement with reduction (DDWR), and disk displacement without reduction (DDWoR). Demographic information and clinical symptoms of patients in each group were recorded. LPM textures were compared among groups. LPM fasciculation was examined. P<0.05 indicated significant difference.

RESULTS

Several clinical symptoms and signs, but not age or sex, differed significantly among groups. Oblique sagittal planar MRI revealed significant differences in the parameters of Angular Second Moment, Contrast, Correlation, Inverse Difference Moment, and Entropy between the healthy controls and the 3 patient groups. MRI of the patients, both without and with disk displacement, demonstrated relative uniformity in gray distribution and correlation of gray values, with greater complexity but an unclear texture and no obvious regularity. The proportion of type B LPM fascicles was significantly higher in the DDWR and DDWoR groups CONCLUSION: Temporomandibular disorder, without and with disk displacement, is associated with clinical symptoms and texture analysis values that differ from healthy muscle. The types of LPM fascicles are related to the position of the articular disk.

A New Mechanical Mouth Opener for Dynamic Magnetic Resonance Imaging of the Temporomandibular Joint

(1) Background: During the magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ), it is necessary to scan the joints in the closed- and open-jaw position, as well as in the maximally open-jaw position. In order to examine both joints in these positions, an MRI compatible mouth opener is required, which allows the articular surfaces to maintain their position stably. (2) Methods: In this study, we included 200 patients aged 18 to 65, with various levels of clinical severity. The mouth opener is made of polymethyl methacrylate and used for dynamic imaging of TMJ. It is in the form of an arrow, with incisures on upper and lower surfaces 1 mm apart and these match possible variations in jaw opening. All the patients were scanned with mouth opener and, immediately after this scanning, with syringe (20 ccm) as a standard device used for mouth opening in clinical setting. (3) Results: A total of 200 MR examinations of TMJs were performed and the mechanical mouth opener was successfully applied without artifacts in all patients. The mouth opener device proved to be adequate in case of MRI of the TMJ for different ranges of mouth opening with the proper protocol for provoked imaging, because the incisures are located at a distance of 1 mm and no objective artifacts were observed in any examination that degraded the diagnostic quality of the examination. (4) Conclusions: The design of the acrylate mouth opener is precisely defined, and it has a purpose in the MRI diagnosis of TMJ disorders.

A Bibliometric Analysis of Research on Temporomandibular Joint Disc Displacement from 1992 to 2022

The temporomandibular joint (TMJ) disc displacement is the most common temporomandibular disorders (TMD) condition. It causes clicking, pain, limited mandibular movements, and even masticatory difficulties in many people. The aim of this study is showcasing hotspots and frontiers in the field and providing a reference for the future research by a bibliometric analysis. Studies published from 1992 to 2022 were retrieved from Web of Science Core Collection on 23 April 2023. A total of 1882 studies (1739 articles and 143 reviews) were included in the bibliometric analysis. From 1992 to 2022, the annual number of publications and citations greatly increased. The United States of America (USA) contributed the most publications about TMJ disc displacement. Shanghai Jiao Tong University was the most productive institution; meanwhile, Yang, C. from this institution was the most prolific author. The University of Washington was the most influential institution, and Brooks, S. was the most influential author. Diagnostic criteria and management of TMJ disc displacement, as well as TMJ disc displacement-associated conditions, might be a hotspot for current global research. We provided an objective and valuable reference for future research on TMJ disc displacement.

Counselling treatment versus counselling associated with jaw exercises in patients with disc displacement with reduction-a single-blinded, randomized, controlled clinical trial

OBJECTIVE

To compare effectiveness of counselling program versus counselling program plus jaw exercises to reduce pain and click in patients with temporomandibular joint disc displacement with reduction (DDWR).

MATERIALS AND METHODS

Patients were divided into two groups: instructions for temporomandibular disorders (TMD) plus jaw exercises (test, n = 34), only TMD instructions (control, n = 34). Pain was analyzed by palpation (RDC/TMD). It was investigated if the click caused discomfort. Both groups were evaluated at baseline, 24 h, 7 days, and 30 days' post treatment.

RESULTS

The click was present in 85.7% (n = 60). In 30-day evaluation, there was a statistically significant difference between groups in the right median temporal muscle (p = 0.041); and there was a statistically significant difference in treatment self-perception (p = 0.002) and click's discomfort (p < 0.001).

CONCLUSION

The exercise with recommendations showed better results, resolution of the click, and self-perception of the treatment effectiveness.

CLINICAL RELEVANCE

This study presents therapeutic approaches that are easy to perform and that can be monitored remotely. In view of the current stage of the global pandemic, these treatment options become even more valid and useful.

CLINICAL TRIAL REGISTER

This clinical trial was registered at Brazilian Clinical Trials Registry (ReBec) under protocol RBR-7t6ycp ( http://www.ensaiosclinicos.gov.br/rg/RBR-7t6ycp/ ), Date of registration: 26/06/2020.

Efficacy of Occlusal Splints and Low-Level Laser Therapy on the Mandibular Range of Motion in Subjects with Temporomandibular Joint Disc Displacement with Reduction

Aims and Objectives

The study was carried out to evaluate the efficacy of four conservative therapeutic modalities on the mandibular range of motion (MRM) in subjects with anterior disc displacement with reduction (ADDwR) of the temporomandibular joint (TMJ).

Materials and Methods

One hundred patients (64 women and 36 men) were selected, and randomly distributed into four groups. Group I: Subjects receiving behavioral therapy (BT). Group II: Subjects receiving low-level laser therapy (LLLT). Group III: Subjects receiving maxillary anterior repositioning splint (MARS). Group IV: Subjects receiving stabilization splint (SS). The MRM was evaluated for each patient before treatment and after 6 months. Paired t test and one-way analysis of variance (ANOVA) tests were used for statistical analysis followed by a post hoc Tukey test (P ≤ 0.05).

Results

All groups showed significant improvement in MRM after 6 months of treatment (P ≤ 0.05) except for BT. There was a significant improvement for SS and MARS on the different movements of MRM, more than for LLLT and BT (P ≤ 0.05).

Conclusion

The MARS and the SS are effective in increasing the MRM for patients with ADDwR.

Temporomandibular Joint Facts and Foibles

The purpose of this article is to dispel some of the major foibles associated with the etiology and management of TMJ disorders, while presenting some of the facts based on the scientific literature to date. To appreciate this kind of update, the reader must be an "out of the box thinker" which requires openness to new ways of seeing the world and a willingness to accept new concepts based on evolving evidence.

Biomechanics and Derangements of the Temporomandibular Joint

The human temporomandibular joint, is a ginglymo-arthrodial joint. The articular disk serves as a fibrous, viscoelastic structure that allows force distribution and smooth movement of the joint in its normal arrangement during mandibular movements. Most studies suggest that in the normal disk position the posterior band is located at the 12'o clock position within the glenoid fossa in the closed mouth posture. When the biomechanics of the joint is altered, the disk may be displaced creating an abnormal relationship between the disk, condyle, and the eminence that is often referred to as an internal derangement. This article reviews the various presentations of internal derangements.

Efficacy of stabilisation splint and low-level laser therapy for patients with chronic closed lock from non-reducible displaced temporo-mandibular joint discs: A parallel randomised clinical trial

BACKGROUND

Stabilisation splint therapy (SST) and low-level laser therapy (LLLT) are effective-invasive treatment for temporo-mandibular disorder (TMD) patients. However, the specific efficacy of each therapy in patients with chronic closed lock (CCL) from temporo-mandibular joints (TMJ) disc displacement without reduction (DDwoR) remains unknown.

OBJECTIVES

The aim of this study was to assess and compare the efficacy of SST and LLLT alone or in combination in patients with CCL from TMJ DDwoR.

METHODS

This parallel randomised clinical trial included 42 patients who were diagnosed with CCL from TMJ DDwoR. Patients were allocated equally and randomly into three treatment groups: group I received combined SST and LLLT, group II received LLLT and group III received SST. Maximum mouth opening (MMO), visual analogue scale (VAS), muscle and joint palpation scores and time required to achieve normal state were evaluated at baseline, 1, 2, 4 weeks, 3 and 6 months after the intervention. Data were collected and analysed using SPSS software.

RESULTS

Regarding MMO and VAS, a statistically significant improvement was found between group I versus group II and versus group III at all evaluation times. Regarding muscle and joint palpation scores, a statistically significant difference was found between group I versus group III, while non-significant difference was found between group I and group II. A statistically significant faster improvement was found in group I versus group III and versus group II.

CONCLUSION

All treatment modalities can be effective in management of CCL from a TMJ DDwoR cases, but the combined SST and LLLT group seems to provide the best and quickest improvement.

CLINICAL TRIAL REGISTRATION NUMBER

NCT05548894.

Arthroscopic osteoplasty of the medial and anteromedial wall of temporomandibular joint: surgical technique and anatomical considerations

The anterior displacement of the articular disc is the most frequent cause of pathological alterations in the TMJ. Although it is an extremely common pathology, there is no certainty about the aetiopathogenesis of this disease. The main aim of the present report is to describe new anatomical findings that could help clarifying the aetiopathogenesis of this disease and determine a typology of treatment based on the cause of the disease. All the operative records of patients who underwent arthroscopic osteoplasty of the medial TMJ wall in our centre from January 2021 to September 2021 were reviewed and analysed to identify specific anatomical features observed in every procedure. Fifty-two joints were included for analysis in this study. Twenty-two joints were classified as Wilkes stages II-III and 30 as Wilkes stages IV-V. The most common complication observed in our sample was the dysaesthesias found in the temporal and preauricular regions. Other complications observed were frontal branch paresis (n = 2), intraoperative bleeding (n = 1), and postoperative malocclusion (n = 1). The compression of the superior head of pterygoid lateral muscle (SPLM) on the medial bony wall and the consequent muscle atrophy could be key for the aetiology of the anterior TMJ disc displacement. Therapeutic actions on the osseous and muscular component in this anatomical area could improve the outcomes of patients affected by TMJ internal derangement. A meticulous dissection of the fascia of the superior fascicle of the lateral pterygoid muscle allows a remodelling of the bone surfaces with minimal complications.

The Emergencies in the Group of Patients with Temporomandibular Disorders

Temporomandibular disorder is a musculoskeletal disease with complex, multifactorial etiology regarding improper functioning of the stomatognathic system (masticatory muscles, temporomandibular joints, and surrounding structures). This article presents medical emergencies occurring among patients treated for temporomandibular disorders, which tend to constitute a severe difficulty for practitioners during their clinical practice. Examples of the most common emergencies of this type are disc displacement without reduction and a sudden contraction of the inferior part of the lateral pterygoid muscle. The latter occurs in cases of uncontrolled and incorrect use of the anterior repositioning splints and the hypertrophy of the coronoid process of the mandible. The sudden attacks of pain of secondary trigeminal neuralgia are also discussed in this article, together with their specific nature, which is significantly different from the nature of the pain of primary trigeminal neuralgia, yet the two types of neuralgia can be easily confused when the primary one takes the painful form. Subsequent emergencies discussed are myofascial pain syndrome, traumatic and inflammatory states of the temporomandibular joints, subluxation, and the consequences of intense occlusive parafunctions. Finally, the recommended therapeutic methods, which are used as part of the treatment in the cases of aforementioned emergencies, are described in this mini-review article, emphasizing that the implementation of the incorrect treatment and rehabilitation for emergencies of temporomandibular disorders may lead to permanent damage to the soft tissue structures of the temporomandibular joints.

Painful Temporomandibular Joint Clicking: Genetic Point of View

AIMS

To determine whether there is an association between gene polymorphisms and patients with painful temporomandibular joint (TMJ) clicking when compared to patients with painless TMJ clicking and a healthy control group.

METHODS

In this pilot study, the genotypic and allelic frequencies of candidate single-nucleotide polymorphisms (SNP) were compared among 60 individuals divided equally into three groups: patients with painful TMJ clicking (n = 20); patients with painless TMJ clicking (n = 20); and healthy controls (n = 20). Participants were genotyped for the following SNPs using real-time polymerase chain reaction: MMP1 -16071G/2G, COMT Val158Met, TNFα -308, IL1β +3954, IL6 -174, and IL10 -1082. The pressure pain threshold (PPT) of the TMJ was also assessed. All variables were compared among groups.

RESULTS

Patients with painful TMJ clicking had a significant association and a higher frequency of MMP1 -16071G/2G (P = .042), COMT Val158Met (P = .030), and TNFα -308 (P = .016) when compared to the other groups, as well as a lower frequency of IL10 -1082. Considering PPT values, a progressively lower mean was found in individuals with painful TMJ clicking, followed sequentially by the painless TMJ clicking and the control groups.

CONCLUSION

This pilot study showed that patients with painful TMJ clicking had a significant association with mutant genotypes related to degradation of extracellular matrix components, pain, proinflammation, and anti-inflammation. Furthermore, these patients also had significantly lower TMJ PPT values in all comparisons.

Temporomandibular Disorders and Bruxism among Sex Workers-A Cross Sectional Study

Sex workers are a highly underprivileged population which is present all around the world. Sex work is associated with negative social stigma which affects all aspects of the sex workers' lives including healthcare, service providers and police. The stigma may result in increased stress, mental health problems, feelings of isolation and social exclusion. In the present study, 36 sex workers (SW) and 304 subjects from the general population in Israel (GP) were evaluated for the presence of bruxism and Temporomandibular disorders (TMD), with the use of Diagnostic Criteria for Temporomandibular Disorders (DC/TMD- Axis I). When compared to the general population, sex workers presented larger maximal assisted mouth opening and higher prevalence of the following TMD diagnoses: Disc displacement with reduction, Myalgia, Myofascial pain with referral, Arthralgia (left and right) and Headache attributed to TMD. The odds of sex workers suffering from one of these diagnoses were twice to five times higher than those of the general population. The study shows that health problems of sex workers go beyond venereal diseases, HIV and mental disorders which are commonly studied. Oral health, TMD and oral parafunctions are some of the additional health issues that should be addressed and explored in this population.

Athrocentesis: What, When, and Why?

The introduction of temporomandibular joint (TMJ) arthroscopy by Onishi in 1970 (results published in 1975 and 1980) opened a new modality for TMJ treatment. The efficiency of arthroscopic lavage and lysis led in the 1990s to its simplification: TMJ arthrocentesis. Always associated with load control, physiotherapy, and elimination of any occlusal hazards, arthrocentesis, a simple procedure, entails less expensive and more available tools and is performed under local anesthesia. Although lacking direct visual inspection of the joint structures, it has become quite popular. Arthrocentesis is most efficient in localized joint pain and limited joint movements such as closed lock, anchored disc phenomenon, osteoarthritis, and various inflammatory diseases. In clicking joint, the results are somewhat controversial. The efficiency of arthrocentesis elicited many enquiries that led to the study and a better understanding of joint function and dysfunction and the actual role of disc location. The release of closed lock without disc repositioning was quite surprising; it improved our understanding of the pathogenesis of closed lock and led to the discovery of the anchored disc phenomenon. This was followed by the awareness of the joint-lubrication system and, in turn, alternative suggestions for the pathogenesis of TMJ disc displacement with and without reduction, open lock, and osteoarthritis, and ultimately by the development of an effective bio-lubricant. Awareness of the role of joint overloading led to the development of an interocclusal appliance that reduces intraarticular pressure; it has become a "must" support for arthrocentesis and any surgical intervention. In our view, arthrocentesis is the definitive indication of the need for surgical intervention and, therefore, should be the first in the cascade of interventions in TMJ disorders.

Double-Puncture Versus Single-Puncture Arthrocentesis: A Randomized Controlled Trial with 3 Years of Follow-Up

AIMS

To compare the clinical effectiveness of conventional double-puncture vs single-puncture type 2 arthrocentesis for management of temporomandibular joint (TMJ) disc displacement without reduction (DDWOR) after 3 years of follow-up.

METHODS

A total of 26 patients with DDWOR were randomly and blindly allocated into two treatment groups (n = 13 each): group 1 = conventional double-puncture arthrocentesis; group 2 = single-puncture type 2 arthrocentesis. Data on gender, side of painful joint complaint, age (years), duration of joint pain (months), maximum interincisal distance (MID, mm), and pain intensity (self-reported with a 0-10 visual analog scale [VAS]) were collected. VAS scores and MID were measured before (baseline) and 3 years after (final) the arthrocentesis.

RESULTS

Twenty-three patients completed the study (group 1, n = 11; group 2, n = 12). Both techniques resulted in significantly reduced VAS scores and increased MID (P = .001) after the 3 years of follow-up; however, there were no statistically significant differences between techniques (P > 0.05).

CONCLUSION

The two arthrocentesis methods tested were both effective in reducing VAS scores and increasing MID in patients with DDWOR.

Advantages of deep learning with convolutional neural network in detecting disc displacement of the temporomandibular joint in magnetic resonance imaging

This study investigated the usefulness of deep learning-based automatic detection of anterior disc displacement (ADD) from magnetic resonance imaging (MRI) of patients with temporomandibular joint disorder (TMD). Sagittal MRI images of 2520 TMJs were collected from 861 men and 399 women (average age 37.33 ± 18.83 years). A deep learning algorithm with a convolutional neural network was developed. Data augmentation and the Adam optimizer were applied to reduce the risk of overfitting the deep-learning model. The prediction performances were compared between the models and human experts based on areas under the curve (AUCs). The fine-tuning model showed excellent prediction performance (AUC = 0.8775) and acceptable accuracy (approximately 77%). Comparing the AUC values of the from-scratch (0.8269) and freeze models (0.5858) showed lower performances of the other models compared to the fine-tuning model. In Grad-CAM visualizations, the fine-tuning scheme focused more on the TMJ disc when judging ADD, and the sparsity was higher than that of the from-scratch scheme (84.69% vs. 55.61%, p < 0.05). The three fine-tuned ensemble models using different data augmentation techniques showed a prediction accuracy of 83%. Moreover, the AUC values of ADD were higher when patients with TMD were divided by age (0.8549–0.9275) and sex (male: 0.8483, female: 0.9276). While the accuracy of the ensemble model was higher than that of human experts, the difference was not significant (p = 0.1987–0.0671). Learning from pre-trained weights allowed the fine-tuning model to outperform the from-scratch model. Another benefit of the fine-tuning model for diagnosing ADD of TMJ in Grad-CAM analysis was the deactivation of unwanted gradient values to provide clearer visualizations compared to the from-scratch model. The Grad-CAM visualizations also agreed with the model learned through important features in the joint disc area. The accuracy was further improved by an ensemble of three fine-tuning models using diversified data. The main benefits of this model were the higher specificity compared to human experts, which may be useful for preventing true negative cases, and the maintenance of its prediction accuracy across sexes and ages, suggesting a generalized prediction.

A clinical study on the incidence of internal derangement of the temporomandibular joint following harvesting of temporalis fascia

OBJECTIVE

The aim of the current clinical study was to reveal whether harvesting of a temporalis fascia graft would be associated with a higher incidence of temporomandibular joint (TMJ) internal derangement.

METHODS

The study group involved 104 patients who had middle-ear operations, 67 of which involved harvesting of temporalis fascia and 37 that did not. The TMJs were clinically examined in each group.

RESULTS

The total incidence of internal derangement of the TMJ was significantly higher in the group that had temporalis fascia harvesting (79.1%), compared to the group that did not have temporalis fascia harvesting (29.7%), (p= 0.001).

CONCLUSION

Harvesting of temporalis fascia probably alters mandibular kinematics and predisposes to internal derangement of the TMJs.

Remote physical examination for temporomandibular disorders

ABSTRACT

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

Development of core outcome sets for clinical trials in temporomandibular disorders: A study protocol

Background

Temporomandibular Disorder (TMD) is a generic term applied to describe musculoskeletal disorders that affect the temporomandibular joint (TMJ), the masticatory muscles and the related structures. TMD comprises two groups of disorders, namely intra-articular TMD and masticatory muscle disorders. There is still difficulty in establishing the effectiveness of different therapeutic modalities for TMD with robust evidence, despite the large volume of publications in the area. The lack of outcomes standardization may represent a limiting factor in the search for scientific evidence.

Objective

This study aims to develop a core outcome sets (COS) for clinical trials in intra-articular TMD and masticatory muscle disorders.

Methods

The protocol for determining the COS-TMD will consist of three phases: 1. Synthesis of TMD Management Intervention Outcomes. The identification of outcomes will be carried out through a systematic review, which will include randomized clinical trials that evaluated the effectiveness of interventions used in TMD management. 2. Through a two-round international Delphi survey, the list of outcomes will be scored by three panels of stakeholders. 3. A representative sample of key stakeholders will be invited to participate in a face-to-face meeting where they can discuss the results of the Delphi survey and determine the final core set.

Conclusions

The implementation of this protocol will determine the COS-TMD, which will be made available for use in all TMD clinical studies. The use of COS when planning and reporting TMD clinical trials will reduce the risk of publication bias and enable proper comparison of results found by different studies.

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

Action of Hyaluronic Acid as a Damage-Associated Molecular Pattern Molecule and Its Function on the Treatment of Temporomandibular Disorders

The temporomandibular joint is responsible for fundamental functions. However, mechanical overload or microtraumas can cause temporomandibular disorders (TMD). In addition to external factors, it is known that these conditions are involved in complex biological mechanisms, such as activation of the immune system, activation of the inflammatory process, and degradation of extracellular matrix (ECM) components. The ECM is a non-cellular three-dimensional macromolecular network; its most studied components is hyaluronic acid (HA). HA is naturally found in many tissues, and most of it has a high molecular weight. HA has attributed an essential role in the viscoelastic properties of the synovial fluid and other tissues. Additionally, it has been shown that HA molecules can contribute to other mechanisms in the processes of injury and healing. It has been speculated that the degradation product of high molecular weight HA in healthy tissues during injury, a low molecular weight HA, may act as damage-associated molecular patterns (DAMPs). DAMPs are multifunctional and structurally diverse molecules that play critical intracellular roles in the absence of injury or infection. However, after cellular damage or stress, these molecules promote the activation of the immune response. Fragments from the degradation of HA can also act as immune response activators. Low molecular weight HA would have the ability to act as a pro-inflammatory marker, promoting the activation and maturation of dendritic cells, the release of pro-inflammatory cytokines such as interleukin 1 beta (IL-1β), and tumor necrosis factor α (TNF-α). It also increases the expression of chemokines and cell proliferation. Many of the pro-inflammatory effects of low molecular weight HA are attributed to its interactions with the activation of toll-like receptors (TLRs 2 and 4). In contrast, the high molecular weight HA found in healthy tissues would act as an anti-inflammatory, inhibiting cell growth and differentiation, decreasing the production of inflammatory cytokines, and reducing phagocytosis by macrophages. These anti-inflammatory effects are mainly attributed to the interaction of high-weight HA with the CD44 receptor. In this study, we review the action of the HA as a DAMP and its functions on pain control, more specifically in orofacial origin (e.g., TMD).

Measuring Changes in Jaw Opening Forces to Assess the Degree of Improvement in Patients with Temporomandibular Disorders

Background: Currently, the degree of improvement in patients with TMDs is measured through subjective questionnaires and clinical examination This study aimed to investigate the properties of an objective quantitative measure of jaw-opening forces to assess clinical improvement in temporomandibular disorder (TMD) patients following treatment. Methods: Baseline jaw-opening forces were recorded for TMD-patients (n = 62) and a comparison group of TMD-free participants (n = 56), using a jaw-opening forces measuring device. TMD patients were divided into three subcategories (myofascial pain, disc-displacement, and myofascial pain and disc-displacement combined) and received a combination of treatment for six months; meanwhile, TMD-free participants did not receive treatment. Jaw-opening forces for each participant in both groups were measured at their six-month review appointment. Results: Jaw-opening forces were reliable at baseline (single measure ICC 0.98, 95% CI 0.97–0.98, ICC ≥ 0.94 for all groups and subcategories). Jaw-opening forces increased in the TMD group following treatment at six-months (18.6 N at baseline and 32.4 N at six-months, p < 0.001) and did not change significantly in the TMD-free group (49 N at baseline and 48.3 N at six-months). There was a small improvement in the disc displacement group (27.8% higher forces, p = 0.002). However, the myofascial-pain and myofascial-pain-and-disc-displacement groups showed significant improvement following treatment (93.5% higher forces, p < 0.001; 91.1% higher forces, p < 0.001; respectively). Conclusion: This study demonstrated that the measurement of jaw-opening forces could potentially be used to assess the clinical improvement in TMD patients following diagnosis and treatment.

Volumetric analysis of normal condyles and those with disc displacement with reduction in the Indonesian population: A CBCT study

Purpose

Disc displacement can cause resorption of the head of the condyle and affect its volume. This study analysed the volume of normal condyles and those with disc displacement with reduction (DDR) in cone-beam computed tomography (CBCT) scans from the Indonesian population.

Materials and Methods

This study analysed 56 condyles (26 normal and 30 with DDR) from patients who visited the Oral and Maxillofacial Radiology Unit after being referred from the Prosthodontics Unit at Dental Hospital Universitas Padjadjaran from December 2020 to February 2021. Samples were divided into 2 groups (normal and DDR left and right-side condyles) based on the DC/TMD Axis 1 form through the clinical examination results. Both sample groups were exposed to CBCT radiation. The CBCT imaging results in the Digital Imaging and Communications in Medicine format were exported to the open-source ITK-SNAP format to determine condyle volume. Volumetric data from the cortical and trabecular areas of the right or left side condyles were arranged by sex. The independent t-test was used to determine the significance of differences with IBM SPSS version 21.0. Intra- and inter-observer reliability and validity were tested before determining the volume of the condyles.

Results

Normal condyles and DDR condyles showed significant differences in volume (P<0.05). Significant differences were also seen in cortical (P=0.0007) and trabecular (P=0.0045) volumes. There was a significant difference in condylar volume based on sex.

Conclusion

The normal condyle volume was significantly different from the DDR condyle volume in both sexes.

Magnetic Resonance Imaging Evaluation of Closed-Mouth TMJ Disc-Condyle Relationship in a Population of Patients Seeking for Temporomandibular Disorders Advice

Objective

To characterize the closed-mouth temporomandibular joint (TMJ) disc-condyle relationship in a population of individuals who sought hospital services for temporomandibular disorders (TMD).

Methods

Two hundred and twenty-four TMJ magnetic resonance images (MRIs) of 112 patients were assessed in all spatial planes to classify disc position with respect to the condyle in a closed-mouth position.

Results

Disc displacement (DD) was present in 62.1% and superior disc position in 29.9% of the patients. Position could not be determined in 8% of the cases. Among DD, pure anteriorized position was the most common condition (34.4%), with different combined translational and rotational displacements in all the other joints (27.7%).

Conclusion

There is a wide biological variability in disc position in closed mouth among patients seeking for TMD advice. Getting deeper into the correlation with clinical symptoms is recommended to refine the potential relevance of any diagnostic and management strategies based on the imaging evaluation of TMJ disc position.

Oral health-related quality of life of patients with acute and chronic temporomandibular disorder diagnostic subtypes

BACKGROUND

Studies have indicated the negative effects of temporomandibular disorders (TMDs) on oral health-related quality of life (OHRQoL). The authors investigated the OHRQoL of patients with acute and chronic TMD subtypes.

METHODS

The authors recruited a total of 830 patients. They derived TMD diagnoses using the Diagnostic Criteria for TMDs protocol involving symptom history, physical examination, and diagnostic imaging as indicated. The authors categorized patients into acute (≤ 3 months) or chronic (> 3 months) pain-related TMD (PT), nonpainful intra-articular TMD (IT), and combined TMD (CT) groups. They also gathered sociodemographic information and assessed OHRQoL with the Oral Health Impact Profile (OHIP)-TMDs. The authors evaluated data using 2-way analysis of variance and Bonferroni test and multiple regression analysis.

RESULTS

Patients in the chronic PT and CT subgroups had significantly higher mean global OHIP scores than their acute counterparts. The authors observed significant acute-chronic differences in OHIP-TMDs domain scores in 5 and 2 domains for the PT and CT groups, respectively. Patients in the acute IT group had significantly higher functional limitation scores than those in the chronic IT group. The ranking of mean global scores, in descending order was CT, PT, and IT for acute TMDs and PT, CT, and IT for chronic TMDs, with significant differences observed among the 3 TMD subtypes (P < .001).

CONCLUSIONS

Both TMD chronicity and subtypes influenced OHRQoL. Painful TMDs (PT and CT) were associated with significantly poorer OHRQoL than nonpainful TMDs. TMD chronicity appeared to affect OHRQoL only for the painful TMD conditions. Future work on the impact of TMDs on OHRQoL should strive to stratify patients by TMD chronicity and subtypes.

PRACTICAL IMPLICATIONS

TMD chronicity and subtypes influence the impact of TMDs on OHRQoL. Given that chronic painful TMDs impair quality of life, early biopsychosocial intervention of acute TMD pain is important for minimizing chronification and OHRQoL deterioration.

Oral behaviors, bruxism, malocclusion and painful temporomandibular joint clicking: is there an association?

The present cross-sectional case-control study aimed to determine if there is an association between specific oral behaviors, sleep bruxism (SB), awake bruxism (AB), and painful temporomandibular joint (TMJ) clicking. Ninety individuals were dived into three groups; Group 1 (n = 30): painful TMJ clicking; Group 2 (n = 30): painless TMJ clicking; and Group 3 (n = 30): control group. The following clinical data were studied: oral behaviors (unilateral chewing, gum chewing, nail biting, foreign objects biting, leaning with jaw against the hand, and sleeping in a position that pressures the jaw), SB, AB (including the frequency in 10 days, evaluated by ecological momentary assessment), and malocclusions investigated based on clinical inspections (anterior open bite, posterior cross-bite, abnormal overbite/overjet, occlusal guidance, mediotrusive and/or laterotrusive interferences, retruded contact position to maximum intercuspation slide, missing posterior teeth). All statistical tests (Kolmogorov-Smirnov, chi-square, and one-way ANOVA) were performed with a 5% significance level. Group 1 had the highest frequency of and a significant association with leaning with jaw in the hand, sleeping position that pressures the jaw, gum chewing, nail biting, and AB (p<0.05). Gum chewing, nail biting, and AB were associated with Group 2 only when compared to Group 3 (p<0.05). No significant difference among groups was found for other behaviors (unilateral chewing and foreign objects biting), SB, and all malocclusions (p>0.05). It can be concluded that patients with painful TMJ clicking had a higher frequency of and a significant association with some specific harmful behaviors and AB.

Biomechanical effects of high acceleration on the temporomandibular joint

The symptoms of temporomandibular disorders (TMD) are easily developed in pilots after long flights, such as joint pain, anterior displacement disc and so on. Related studies have suggested that abnormal high acceleration would cause temporomandibular joint (TMJ) lesions. Therefore, the purpose of this study is to analyze the biomechanical effects of high acceleration on the TMJs. The 3D models of the maxilla, mandible, articular disc were generated by Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) of a healthy volunteer without any TMD symptoms. Then, the loads were added according to the various operating conditions of the aircraft. The maximum tensile stress, occurred in the anterior band of the discs, exceeded the failure stress. Compared with the low acceleration, the contact stresses between the discs and the articular cartilages were much greater under the high acceleration. High acceleration had a negative impact on the stress distributions of the articular discs and cartilages and easily led to TMJ damage. Lateral acceleration will cause asymmetric stress distribution of the TMJs.

Automated cortical thickness measurement of the mandibular condyle head on CBCT images using a deep learning method

This study proposes a deep learning model for cortical bone segmentation in the mandibular condyle head using cone-beam computed tomography (CBCT) and an automated method for measuring cortical thickness with a color display based on the segmentation results. In total, 12,800 CBCT images from 25 normal subjects, manually labeled by an oral radiologist, served as the gold-standard. The segmentation model combined a modified U-Net and a convolutional neural network for target region classification. Model performance was evaluated using intersection over union (IoU) and the Hausdorff distance in comparison with the gold standard. The second automated model measured the cortical thickness based on a three-dimensional (3D) model rendered from the segmentation results and presented a color visualization of the measurements. The IoU and Hausdorff distance showed high accuracy (0.870 and 0.928 for marrow bone and 0.734 and 1.247 for cortical bone, respectively). A visual comparison of the 3D color maps showed a similar trend to the gold standard. This algorithm for automatic segmentation of the mandibular condyle head and visualization of the measured cortical thickness as a 3D-rendered model with a color map may contribute to the automated quantification of bone thickness changes of the temporomandibular joint complex on CBCT.