Disc displacement within the human temporomandibular joint: a systematic review of a ‘noisy annoyance’

Development and Validation of the Epidemiological Diagnostic Instrument for Temporomandibular Disorders

BACKGROUND

Temporomandibular disorders (TMD) are a highly misreported health problem. Its diagnosis is complex and requires the use of valid and reliable instruments.

OBJECTIVE

To develop and validate the Epidemiological Diagnostic Instrument for TMD (EDI/TMD).

METHODS

Content validity (CV), response process (RP), construct validity (EFA), reliability (inter and intraobserver consistency), and convergence validity of the EDI/TMD were assessed and compared to the Diagnostic Criteria for TMD (DC/TMD).

RESULTS

An instrument composed of a 9-question questionnaire and a 12-step clinical protocol was developed. CV analysis reduced the instrument to a 5-question and 7-step clinical protocol (CVI = 0.93). Some instructions were included after the RP. The EFA found three factors: myogenous TMD, arthrogenous TMD, and differential diagnosis. The reliability scores ranged from substantial to excellent. When compared to the DC/TMD, the EDI/TMD total score indicated that this instrument is valid and provides satisfactory diagnostic criteria (Kappa = 0.906; p < 0.001), and can distinguish non-TMD and TMD individuals, with a cut-off point of 4.9 (Sensitivity = 1.0; Specificity = 1.0; AUC = 1.0). For individuals who had both myogenous and arthrogenous TMD, the cut-off point was 14 or higher (Sensitivity = 0.8; Specificity = 1.0; AUC = 0.987). For individuals who had either myogenous TMD (Sensitivity = 1.0; Specificity = 0.88; PPV = 0.89; NPV = 1.0) or arthrogenous TMD (Sensitivity = 0.95; Specificity = 0.87; PPV = 0.83; NPV = 0.96), the cut-off point was between 5 and 13.9, with the highest EFA score being the determinant factor for final diagnosis.

CONCLUSION

Based on its psychometric properties, the EDI/TMD is a valid and reliable assessment tool that is capable of diagnosing TMD and classifying its subtypes.

Dry needling and upper cervical spinal manipulation in patients with temporomandibular disorder: A multi-center randomized clinical trial

OBJECTIVE

To compare the effects of dry needling and upper cervical spinal manipulation with interocclusal splint therapy, diclofenac, and temporomandibular joint (TMJ) mobilization in patients with temporomandibular disorder (TMD).

METHODS

One hundred-twenty patients with TMD were randomized to receive six treatment sessions of dry needling plus upper cervical spinal manipulation (n = 62) or interocclusal splint therapy, diclofenac, and joint mobilization to the TMJ (n = 58).

RESULTS

Patients receiving dry needling and upper cervical spinal manipulation experienced significantly greater reductions in jaw pain intensity over the last 7 days (VAS: F = 23.696; p < 0.001) and active pain-free mouth opening (F = 29.902; p < 0.001) than those receiving interocclusal splint therapy, diclofenac, and TMJ mobilization at the 3-month follow-up.

CONCLUSION

Dry needling and upper cervical spinal manipulation was more effective than interocclusal splint therapy, diclofenac, and TMJ mobilization in patients with TMD.

Is there an association between EMG activity and temporomandibular disorders during orthotic mandibular advancement in sleep apnea patients undergoing DISE?

OBJECTIVE

To detect whether myotatic reflex activation of masticatory muscles during drug-induced sleep endoscopy (DISE) can be an indirect marker for temporomandibular disorder (TMD) in patients suffering from obstructive sleep apnea (OSA).

METHODS

OSA patients were prospectively recruited and underwent a complete TMD examination prior to undergoing DISE with the addition of electrodes applied over masticatory muscles. A positive activation of myotatic reflex was considered in case of an increase in muscle tone of at least 50%.

RESULTS

Of the 41 patients included, 48.8% presented activation of myotatic reflex. Of these patients, 45% presented a TMD diagnosis, 40% presented pain at masticatory muscles palpation, and 15% did not report pain during clinical examination.

CONCLUSION

An increase in EMG activity during mandibular advancement is not associated with TMD presence, but it can be an indirect marker of pain in the orofacial area in OSA patients.

Evaluation of mandibular motions in patients with anterior disc displacement during mouth opening and closing using finite helical axis

Understanding temporomandibular joint (TMJ) kinematics is essential for the clinical diagnosis and treatment of TMJ disorders. Yet, a comprehensive description of mandibular motion information in patients with anterior disc displacement (ADD) is lacking. The finite helical axis (FHA) is a mathematical model describing the motion of a rigid body in space. This model quantifies mandibular motion patterns by differentiating between rotation around the FHA and translation along it. This study aimed to compare the mandibular motion patterns between patients with ADD and asymptomatic subjects during mouth opening and closing utilizing the FHA. Ten asymptomatic subjects (2 females and 8 males, aged 19-22) and ten patients with ADD (8 females and 2 males, aged 19-57) were tracked using an optical motion tracking system for mouth opening and closing. The FHA during mouth opening and closing was determined from motion trajectory. The distance from the condylar center to the FHA (dCP), the angles between the FHA and the head coordinate system (θx, θy, θz), and the global fluctuation of the FHA spatial orientation (θf) were further calculated. In addition, the helical axis of each frame relative to the initial frame was computed to determine the maximum rotation angle (Θmax) and maximum offset (Tmax) of mandibular motion during mouth opening and closing. It was found that Θmax, Tmax, dLCPmean, dLCPmin, θx, and θf for patients with ADD differed significantly from those of asymptomatic subjects. These findings imply that the FHA effectively describes the disparities between patients with ADD and asymptomatic subjects.

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

BACKGROUND AND AIM

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

RESULTS

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

CONCLUSIONS

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

Morphologic characteristics of temporomandibular joint on the patients with anterior disc displacement without osteoarthritis: a case-based research

We investigated the effect of anterior disc displacement without osteoarthritis (ADDwoOA) on the morphology of the temporomandibular joint (TMJ) utilizing three-dimensional (3D) models of 23 asymptomatic individuals and 30 ADDwoOA patients. Statistical analyses between the groups were performed by measuring 10 morphological parameters. ADDwoOA patients showed significantly decreased levels of the sagittal ramus angle (SRA) and joint spaces compared with asymptomatic subjects. Moreover, the patients who had recovered exhibited normal joint spaces levels. Consequently, ADDwoOA caused the condyles to move backward and upward, approaching the articular fossa. Joint spaces can serve as an important observation during the treatment of ADD.

Influence of examiner calibration on clinical and MRI diagnosis of temporomandibular joint disc displacement: a systematic review and meta-analysis

OBJECTIVES

This study aimed to verify the accuracy of clinical protocols for the diagnosis of disc displacement (DD) compared with MRI, considering examiners' calibration.

METHODS

PubMed, Cochrane (Central), Scopus, Web of Science, LILACS, Embase, Science Direct, Google Scholar, and DANS EASY Archive databases were searched. Two reviewers independently screened and selected the studies. A meta-analysis was conducted using the R Statistical software. Results are shown using sensitivity and specificity, and 95% confidence intervals.

RESULTS

Of the 20 studies included in the systematic review, only three were classified as low risk of bias. Seventeen studies were included in the meta-analysis. Compared to MRI, clinical protocols showed overall sensitivity and specificity of 0.75 (0.63-0.83) and 0.73 (0.59-0.84) for DD diagnosis, respectively. For DD with reduction, sensitivity was 0.64 (0.48-0.77) and specificity was 0.72 (0.48-0.87). For DD without reduction, sensitivity was 0.58 (0.39-0.74) and specificity 0.93 (0.83-0.97). Only 8 studies reported examiner calibration when performing clinical and/or MRI evaluation; nevertheless, calibration showed a tendency to improve the diagnosis of DD.

CONCLUSION

The sensitivity and specificity of clinical protocols in the diagnosis of DD are slightly below the recommended values, as well as the studies lack calibration of clinical and MRI examiners. Examiner calibration seems to improve the diagnosis of DD.

Salubrinal alleviates cartilage degradation in a rabbit temporomandibular joint osteoarthritis model

OBJECTIVE

To investigate and explain the beneficial effects of local intra-articular injection of Salubrinal on temporomandibular joint osteoarthritis (TMJOA) using a rabbit model of anterior disc displacement (ADD).

METHODS

Rabbits were divided and subjected to surgical ADD. Salubrinal was administered by intra-articular injection in the TMJ every other day for 2 and 4 weeks after operation. Histological examination and TUNEL staining were then performed. Immunohistochemistry, quantitative real-time PCR, and Western blot analysis were employed to evaluate the expression of endoplasmic reticulum (ER) stress-related markers, catabolic factors, extracellular matrix proteins, inflammatory factors, and nuclear factor-kappa B (NF-κB) activation.

RESULTS

In the ADD groups, we found that Salubrinal partly reversed condylar cartilage deterioration according to the histological analysis. Salubrinal reduced chondrocytes apoptosis while increased matrix components including Collagen II and Aggrecan. Meanwhile, Salubrinal downregulated the catabolic expression of MMP13, ADAMTS5, VEGF, TNF-α, and IL-1β. We also observed that Salubrinal inhibited ER stress activation by reducing the expression of GRP78, CHOP, ATF4, and Caspase-12. Additionally, Salubrinal suppressed the phosphorylation of NF-κB.

CONCLUSION

These results indicate that Salubrinal alleviates cartilage degradation following ADD, suggesting that intra-articular injection of Salubrinal is a potential therapeutic approach for preventing TMJOA.

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.

Obstructive sleep apnea treatment improves temporomandibular disorder pain

PURPOSE

The existence of a bidirectional relationship between poor sleep and pain intensity has been studied, and good sleep quality has been found to be a key factor underlying pain control. The purpose of this prospective cohort study was to observe if OSA treatment provides a reduction in temporo-mandibular disorder (TMD) pain and headache attributed to TMD in patients with obstructive sleep apnea (OSA) after 18 months of OSA treatment.

METHODS

A prospective cohort study was conducted on consecutive patients suffering from OSA. Patients underwent polysomnography and TMD examination according to the DC/TMD protocol at baseline and after 18 months. Intensity of TMD pain and headache attributed to TMD were analyzed.

RESULTS

Of 40 patients (31 men, mean age 51.3 ± 10.3 years), 33 underwent OSA treatment. At the follow-up examination after 18 months, significant improvements in the intensity of pain-related TMD and headache attributed to TMD were observed (p < 0.05). Seven patients did not start treatment for OSA or discontinued treatment. These patients did not show any significant difference in intensity of TMD-pain or headache attributed to TMD after 18 months (p > 0.05).

CONCLUSIONS

Significant reductions in intensity of pain-related TMD and headache attributed to TMD were observed in patients with OSA after 18 months of OSA treatment onset, while no difference was observed in subjects not undergoing or discontinuing OSA treatment.

TRIAL REGISTRATION

The protocol was registered on ClinicalTrials.gov database with number NCT04948541.

Effect of arthroscopic discopexy on condylar growth in adolescents with temporomandibular joint disc displacement without reduction: A retrospective self-controlled case series study

This study was a retrospective self-controlled study that aimed to evaluate the effect of arthroscopic discopexy on condylar height and mandibular position in adolescents with temporomandibular joint (TMJ) anterior disc displacement without reduction (ADDwoR). Patients between 10 and 20 years of age and diagnosed with bilateral TMJ ADDwoR by magnetic resonance image (MRI) were included in this study. All patients underwent a period of natural course before arthroscopic surgery and then a follow-up period postoperatively. Changes in condylar height and mandibular position were measured by MRI and X-ray radiographs. Data were analyzed by paired t-test, Pearson correlation analysis, and generalized estimating equations. This study comprised a total of 40 patients with a mean age of 14.80 years. Pearson correlation analysis showed correlations between condylar height and mandibular position changes. The condylar height change during the post-operative period was significantly higher than that during natural course period (3.57 mm, p < 0.001). The changes in mandibular position (including ANB angle, SNB angle, and Pog-Np) were significant different (all p < 0.05) between the two periods. This study found that arthroscopic discopexy can promote condylar growth and correct dentofacial deformity in adolescents with bilateral TMJ ADDwoR.

Treatments for painful temporomandibular disc displacement with reduction: a network meta-analysis of randomized clinical trials

There is currently no consensus on the best treatment for painful temporomandibular disc displacement with reduction (DDwR), and no network meta-analysis of randomized clinical trials (RCTs) comparing all types of treatment for this condition has been conducted. The objective of this study was to compare and rank all treatments for DDwR, including conservative treatments, occlusal splints, low-level laser therapy (LLLT), manual therapy, no treatment (control), arthrocentesis (Arthro) alone, Arthro plus intra-articular injection of platelet-rich plasma (Arthro-PRP) or hyaluronic acid (Arthro-HA), and Arthro plus occlusal splint. Predictor variables were pain intensity and maximum mouth opening (MMO). The mean difference with 95% confidence interval was estimated using Stata software. The GRADE system was used to assess the certainty of the evidence. Twenty RCTs reporting 1107 patients were identified in the literature search; 980 of these patients were included in the network meta-analysis. Direct meta-analysis showed that Arthro-PRP significantly reduced pain intensity compared to Arthro alone, while occlusal splint and manual therapy were superior to conservative treatment (all very low quality evidence). Arthro with intra-articular injection of PRP/HA ranked as the most effective treatment in terms of pain reduction, whereas LLLT ranked the best choice for increasing MMO for patients with DDwR. However, it is important to note that the evidence for the superiority of these treatments is generally of very low quality. Therefore, further high-quality research is needed to confirm these findings and provide more reliable recommendations for the treatment of DDwR.

Occurrence of Temporomandibular Disorders among patients undergoing treatment for Obstructive Sleep Apnoea Syndrome (OSAS) using Mandibular Advancement Device (MAD): A Systematic Review conducted according to PRISMA guidelines and the Cochrane handbook for systematic reviews of interventions

BACKGROUND

Patients undergoing mandibular advancement device (MAD) therapy for obstructive sleep apnea (OSA) may experience changes in jaw position and altered occlusion. This could potentially contribute to the development or exacerbation of TMD symptoms. The literature on the long-term impact of MAD treated for OSA on TMD is scarce. Hence, this review was undertaken to ascertain the occurrence of TMD in MAD users.

METHODS

A comprehensive search protocol was implemented across several online databases using MeSH keywords and Boolean operators. A standardised data extraction form was developed specifically for this review. Two reviewers independently extracted the data. RoB-2 was used to evaluate the methodological quality of the included studies.

RESULTS

A total of 13 clinical studies were selected for this review. Some studies reported a significant reduction in the severity and frequency of TMD symptoms following MAD treatment. However, other studies did not observe significant changes in TMD symptoms or TMJ-related parameters from baseline to follow-up intervals. Temporary increases in TMJ-related pain or symptoms at the beginning of the follow-up period, which later subsided, were reported in some studies. Overall, MAD was not discontinued in any OSA patient due to TMDs.

CONCLUSION

The findings reveal that different outcomes associated with TMD are affected differently by MAD treatment for OSAS. According to a few studies, MAD therapy significantly reduced the severity and frequency of TMD symptoms. Other research, however, found no appreciable modifications in TMD symptoms or TMJ-related indicators. Although the overall results point to no significant effect of MAD treatment on TMD symptoms, the disparity in results between studies highlights the need for additional studies using standardised approaches.

Influence of local factors on the condylar growth after arthroscopic discopexy in adolescents with temporomandibular joint anterior disc displacement without reduction: a retrospective longitudinal study

The aim of this retrospective longitudinal study was to investigate the condylar growth after arthroscopic discopexy in adolescents with temporomandibular joint (TMJ) anterior disc displacement without reduction (ADDwoR), and to determine whether local or systemic factors influence this growth. A total of 145 patients aged 10-20 years who were diagnosed with ADDwoR by magnetic resonance imaging were included. Patients who underwent arthroscopic discopexy were assigned to the arthroscopy group (n = 108) and others to the control group (n = 37). Demographic information, clinical assessments, body indicators, and bone density information were collected. Condylar height, disc length, and disc position were measured. The mean condylar height change in the arthroscopy group was 2.12 mm more than that in the control group (P < 0.001). Condylar growth after surgery was negatively correlated with age (P = 0.017) and disc length (P = 0.015), and positively correlated with follow-up duration (P = 0.002) and disc position (P < 0.001). Moreover, arthroscopic discopexy patients had better outcomes regarding improvements in pain (P = 0.024), maximum inter-incisal opening (P < 0.001), and quality of life (P < 0.001) than control patients. In conclusion, arthroscopic discopexy can restore condylar growth and relieve symptoms in ADDwoR patients, and the condylar growth is closely related to the local factors.

Step-back anterior repositioning splint retraction for temporomandibular joint disc displacement with reduction in adult patients

BACKGROUND

Anterior repositioning splint (ARS) is used to treat temporomandibular joint (TMJ) disc displacement with reduction (DDwR). However, high recurrence rate remains a problem especially in patients with unstable occlusions.

OBJECTIVE

This study optimised standard ARS therapy and proposed a step-back ARS retraction (SAR) method in adult patients with DDwR.

METHODS

Dental examinations and magnetic resonance imaging of TMJ were obtained before treatment (T0), 1 to 3 months (T1), 3 to 6 months (T2) and 6 to 12 months (T3) during treatment in 48 adults (average age 27.1 ± 5.7 years). After 3 months of basic ARS wearing, personalised treatment for patients with normal disc-condyle relationship was prescribed depending on bilaminar zone adaptations and severity of molar openbite. SAR which required sequential ARS wearing was designed for patients with deep overbite/overjet until retrodiscal tissue adaptations and stable occlusions were achieved.

RESULTS

The maximum interincisal opening was increased from 44.3 ± 6.9 to 45.3 ± 6.3 mm (p < .01), and joint pain was alleviated after ARS treatment. The overall success rate of ARS wearing was 92.1% (58/63) featured by a recaptured disc. Fifteen patients who underwent SAR therapy all showed bilaminar zone adaptations in the end, and one patient had positive condylar bone remodelling.

CONCLUSIONS

ARS treatment could improve mouth opening and joint symptoms in adult DDwR patients. SAR method was suitable for treating DDwR patients with deep overbite and overjet and improved retrodiscal tissue adaptations and condylar bone remodelling.

Otological symptoms in patients with rheumatoid arthritis of the temporomandibular joint

OBJECTIVE

The aim of the current study was to describe the pattern of otological symptoms in patients with rheumatoid arthritis (RA), having clinical temporomandibular joint (TMJ) involvement. This issue had not been previously addressed.

METHODS

A questionnaire and examination findings protocol was applied for 141 patients with RA and 141 control subjects.

RESULTS

Otological symptoms (otalgia, hearing loss, tinnitus, and vertigo), all had a significantly higher incidence in RA patients, compared to control subjects (P = .001).

CONCLUSION

The onset and maintenance of otological symptoms in patients with TMJ involvement by RA probably result from peripheral, as well as central nervous system alterations in sensory stimuli programming.

Recommendations on the Use of Oral Orthotic Occlusal Appliance Therapy for Temporomandibular Joint Disorders: Current Evidence and Clinical Practice

Background

'Temporomandibular joint disorders (TMDs)' denote an umbrella term that includes arthritic, musculoskeletal and neuromuscular conditions involving the temporomandibular joint, the masticatory muscles, and the associated tissues. Occlusal devices are one of the common treatment modalities utilized in the conservative management of TMDs. The indications for the available 'oral splints' or 'oral orthotic occlusal devices' remain ambiguous.

Methods

A joint international consortium was formulated involving the subject experts at TMJ Foundation, to resolve the current ambiguity regarding the use of oral orthotic occlusal appliance therapy for the temporomandibular joint disorders based on the current scientific and clinical evidence.

Results

The recommendations and the conclusion of the clinical experts of the joint international consort has been summarized for understanding the indications of the various available oral orthotic occlusal appliances and to aid in the future research on oral occlusal orthotics.

Conclusion

The use of the oral orthotic occlusal appliances should be based on the current available scientific evidence, rather than the archaic protocols.

Malocclusion Complexity in Patients with Disc Displacement Disorders: A Case-Control Study

This study aimed to determine the possible association between disc displacement (DD) disorders and malocclusion complexity. This cross-sectional study was carried out using a case-control design. The Research Diagnosis Criteria for Temporomandibular Disorders were used to identify cases and controls. The Index of Complexity, Outcome, and Need (ICON) was used to quantify malocclusion complexity as easy, mild, moderate, difficult, or very difficult. A total of 310 subjects were included: 130 cases and 180 controls. A binary logistic regression (p < 0.05) was used to identify associations. The odds ratio (OR) was also calculated. DD was associated with sex, age, and malocclusion complexity (p < 0.05). The malocclusion complexity comparison showed that 89.3% of the controls fell within the easy-moderate levels of the ICON, whereas 85.4% of the cases were in the moderate-very difficult levels (p ≤ 0.001). Difficult and very difficult malocclusions had high ORs (9.801 and 9.689, respectively) compared to the easy cases. In conclusion, patients with malocclusion complexity levels classified as difficult or very difficult have greater odds of presenting DD.

High-Field Magnetic Resonance Imaging of the Temporomandibular Joint Low Agreement with Clinical Diagnosis in Asymptomatic Females

(1) Background: The aim of this study was to investigate the agreement between a clinical diagnosis based on research diagnostic criteria/temporomandibular disorders (RDC/TMD) and high-field magnetic resonance imaging (MRI) findings of temporomandibular joints (TMJs) in asymptomatic females. (2) Methods: A prospective study on 100 females (200 TMJs) was performed, using clinical examinations (RDC/TMD) and same-day MRIs of TMJs on a 3T MR unit. The inclusion criteria were as follows: females, age > 18, the presence of upper and lower incisors, and an understanding of the Serbian language. Descriptive statistics (means and standard deviations) and ANOVA with a post hoc Tukey test for differences among the patient subgroups was performed. The agreement between the clinical and MRI findings was determined using Cohen's kappa coefficient (k < 0.21 slight, 0.21-0.4 fair, 0.41-0.6 moderate, 0.61-0.8 substantial, and 0.81-1 almost perfect). The statistical significance was set at p ≤ 0.05. (3) Results: Normal findings were observed in 86.7%, disc dislocation (DD) was observed in 9.2%, and arthralgia/osteoarthritis/osteoarthrosis was observed in 2.6% of TMJs using RDC/TMD. On the MRI, normal findings were observed in 50.5%, disc dislocation was observed in 16.3%, and arthralgia/osteoarthritis/osteoarthrosis was observed in 23.5% of TMJs. The anterior DD with reduction showed fair agreement of the clinical and MRI findings (k = 0.240, p < 0.001) compared with the DD without reduction (k = 0.355, p < 0.001). Both showed high specificity (94.9% and 99.4%) but low sensitivity (24.2% and 25.0%). The sensitivity in osteoarthritic changes was low (4.8%), but the specificity remained high (96.2%). (4) Conclusions: The sensitivity of the clinical examination remains low compared with 3T MRI, especially in osteoarthritic changes and anterior DD with reduction. However, the number of false positive diagnoses using RDC/TMD is low in asymptomatic patients. RDC/TMD remains a sensible method for establishing a clinical diagnosis and avoiding the overtreatment of asymptomatic patients.

Evaluation and management of temporomandibular disorders. Part 2: an orthopaedic physical therapy update on examination and clinical reasoning

Temporomandibular (TM) disorders afflict many people globally and, despite the presence of existing peer-reviewed material that assists conservative orthopedic providers, recent advances in knowledge indicate that updated resources are required for students, clinicians, and educators. This two-part series builds off previously published material to present newer supplementary information that can be useful during the evaluation and management processes. Content in Part 1 of this series includes a discussion about the factors that have been shown to contribute to TM disorders, an updated perspective of relevant pain science, a discussion of self-report outcome measures, and various different topics related to the examination of patients with TM disorders. Part 2 addresses information related to the temporomandibular joint disc, joint hypermobility, oral splints, and clinical reasoning. In combination with other available publications, this two-part series provides clinicians an opportunity to improve their delivery of effective and efficient clinical services for people diagnosed with TM disorders.

Comparison of the Efficacy of Two Protocol Treatments in Patients with Symptomatic Disc Displacement without Reduction: A Randomized Controlled Trial

The aim of this study was to compare the effectiveness of arthrocentesis followed by hyaluronic acid infiltration treatment (ASH) and mandibular exercise therapy (MET) in patients with symptomatic disc displacement without reduction (DDwoR) by examining pain intensity (VAS), mandibular range of motion (MO), and quality of life (QoL). Fifty-two patients were randomly allocated into two groups, MET (N = 26) and ASH (N = 26), and therapy was applied at the baseline and one month after. Patients were followed up at 1 and 12 months after the baseline assessment. Clinical and patient-reported outcomes were compared at the baseline, 1-month follow-up, and 12-month follow-up. The study found no significant differences in VAS and MO between the ASH and MET groups at the baseline. However, while not significant, it was noted that the ASH group showed higher values for MO. Regarding OHIP-14 at 1 month of follow-up, the ASH group showed significant improvements in physical pain (p > 0.01), physical and psychological disability (p = 0.043 and p = 0.029), and handicap (p = 0.033). At the 12-month follow-up, the ASH group showed significant improvements in functional limitation, psychological discomfort, psychological disability, and handicap (p = 0.008, p = 0.001, p = 0.001, p = 0.005, respectively). ASH treatment did not reduce pain or improve mandibular range of motion more than physical therapy in patients with symptomatic DDwoR. However, ASH could be preferable given its positive long-term effects on patients' quality of life. The clinician's main objective is to prioritize the treatment plan order with a focus on the patient's quality of life. Accordingly, healthcare professionals should consider ASH as a treatment option for patients with symptomatic DDwoR who desire long-term improvement in their quality of life.

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.

Classification and Diagnosis of Temporomandibular Disorders and Temporomandibular Disorder Pain

Designing classification systems and developing diagnostic criteria for temporomandibular disorders is difficult. An appreciation of the utility and applicability of these entities requires an understanding of the importance of each, the differences between the two, and how they may be optimally operationalized for both clinical and research activities in light of their inherent advantages and limitations. In addition, consideration for adopting newer approaches, such as following ontological and precision-based medicine principles, accounting for genetics/epigenetic and neurobiological factors, and the inclusion of biomarkers will potentially result in more thorough and comprehensive classification systems and diagnostic criteria.

The Retrospective Study of Magnetic Resonance Imaging Signal Intensity Ratio in the Quantitative Diagnosis of Temporomandibular Condylar Resorption in Young Female Patients

According to the literature, there is no reliable and quantitative method available for the diagnosis and prognosis of early or potential temporomandibular joint (TMJ) condylar resorption (CR) thus far. The purpose of this study was to raise a new noninvasive method to quantitatively evaluate condylar quality using the signal intensity ratio (SIR) on magnetic resonance imaging (MRI) in order to assist in the diagnosis of TMJ CR. A retrospective exploratory study was performed to compare the condyle-to-cerebral cortex signal intensity ratios (SIR) on MRI among young female patients. We included 60 patients, and they were divided into three groups: the bilateral normal TMJ group (group 1), the bilateral TMJ anterior disc displacement (ADD) but without CR group (group 2), and the bilateral TMJ anterior disc displacement (ADD) with CR group (group 3). The SIR difference between the three groups was analyzed by the Kruskal–Wallis test (K-W test). The sensitivity, specificity, accuracy, and area under curve (AUC) were calculated by the receiver operating characteristic (ROC) curves. There was high consistency between the surgeon and the radiologist in the evaluation of the magnetic signal intensity with intraclass correlation coefficients of 0.939–0.999. The average SIR was 1.07 in the bilateral normal TMJ group (group 1), 1.03 in the ADD without CR group (group 2), and 0.78 in the ADD with CR group (group 3). It could be found by the K-W test that group 3 was significantly different from group 1 and group 2 (p < 0.05), while there was no significant difference between group 1 and group 2. The optimal critical SIR value was 0.96 for the diagnosis of CR according to the ROC curves and Youden index (p < 0.001, AUC = 0.9). The condyle-to-cerebral cortex SIR can be used as a noninvasive diagnostic tool for the quantitative evaluation of condylar quality and diagnosis and prognosis of CR. SIR ≥ 0.96 indicates a healthy condyle, while SIR < 0.96 is considered the optimal critical value for the diagnosis of CR. These findings are important for personalized and accurate treatment and prognosis prediction.

Accurate Diagnosis and Treatment of Painful Temporomandibular Disorders: A Literature Review Supplemented by Own Clinical Experience

Introduction

Temporomandibular disorders (TMD) is a multifactorial group of musculoskeletal disorders often with combined etiologies that demand different treatment plans. While pain is the most common reason why patients decide to seek help, TMD is not always painful. Pain is often described by patients as a headache, prompting patients to seek the help of neurologists, surgeons, and ultimately dentists. Due to the unique characteristics of this anatomical area, appropriate diagnostic tools are needed, as well as therapeutic regimens to alleviate and/or eliminate the pain experienced by patients. Aim of the Study. The aim of this study is to collect and organize information on the diagnosis and treatment of pain in TMD, through a review of the literature supplemented by our own clinical experience. Material and Methods. The study was conducted by searching scientific databases PubMed, Scopus, and Google Scholar for documents published from 2002-2022. The following keywords were used to build the full list of references: TMD, pain, temporomandibular joint (TMJ), TMJ disorders, occlusal splint, relaxing splints, physiotherapy TMD, pharmacology TMD, natural therapy TMD, diagnostic criteria for TMD, and DC/TMD. The literature review included 168 selected manuscripts, the content of which was important for pain diagnosis and clinical treatment of TMD.

Results

An accurate diagnosis of TMD is the foundation of appropriate treatment. The most commonly described treatments include physiotherapy, occlusal splints therapy, and pharmacological treatment tailored to the type of TMD.

Conclusions

Based on the literature review and their own experience, the authors concluded that there is no single ideal form of pain therapy for TMD. Treatment of TMD should be based on a thorough diagnostic process, including the DC/TMD examination protocol, psychological evaluation, and cone beam computer tomography (CBCT) imaging. Following the diagnostic process, once a diagnosis is established, a treatment plan can be constructed to address the patient's complaints.

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

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

Temporomandibular disorder: A previously unreported complication of chronic suppurative otitis media

OBJECTIVE

The aim of the current clinical study was to test the hypothesis that chronic suppurative otitis media (CSOM) might be significantly associated with signs of temporomandibular joint (TMJ) internal derangement.

METHODS

The study involved 79 patients with CSOM and 79 control subjects. The TMJ was clinically examined in both groups.

RESULTS

Signs of internal derangement of the TMJ(s) were found in 67.1% of CSOM patients versus 26.6% of control subjects (p = .001).

CONCLUSION

CSOM may be associated with the extension of the inflammatory process into the TMJ, thereby predisposing to internal derangement of the joint.

Promising minimally invasive treatment modalities for symptomatic temporomandibular joint disc displacement with reduction: a randomized controlled clinical trial

BACKGROUND

Pain and clicking are the primary complaints in patients suffering from temporomandibular joint disc displacement with reduction (DDwR), negatively affecting the patients' quality of life, making the treatment essential. This prospective randomized controlled trial (RCT) was conducted to evaluate the effectiveness of botulinum toxin type-A (BTX-A) and low level laser therapy (LLLT) in comparison to anterior repositioning appliance (ARA) for the treatment of DDwR.

METHODS

A total of 27 patients were randomly allocated to 3 groups; ARA (control group), BTX-A, and LLLT; with 9 patients each. All patients were evaluated before and 3 months after the treatment using a visual analogue scale (VAS) and magnetic resonance imaging (MRI).

RESULTS

At 3 months follow-up, all groups showed a significant reduction in pain assessed by VAS (P = 0.007). Measured on MRI, there was a significant improvement in disc position and joint space index (JSI) in BTX-A group (P < 0.001, P = 0.011) and LLLT group (P = 0.002, P = 0.017) in comparison to the control group (P = 0.087, P = 0.066) respectively. As for time of recovery, a statistically significant difference was observed in BTX-A group (P < 0.001) and LLLT (P < 0.001) group in comparison to ARA group, which showed the most prolonged duration for reduction of DDwR symptoms.

CONCLUSION

We concluded that BTX-A and LLLT could be considered effective alternative treatment modalities to ARA regarding reducing joint pain, clicking, and improving disc position in patients with symptomatic DDwR.

TRIAL REGISTRATION

This prospective double-blinded RCT has been registered at ClinicalTrials.gov with identification number: NCT05194488, 18/1/2022.

Cross-sectional and longitudinal assessment of subchondral cysts in temporomandibular joints: Clinical and MRI study with a mean follow-up of 66 months

PURPOSE

This observational study aimed to elucidate the pathophysiology of subchondral cysts (SC) in the temporomandibular joint (TMJ) and examine the results of conservative therapy administered to patients with SCs in the TMJ.

METHODS

The study included 41 patients with SCs, extracted from 684 consecutive patients who underwent magnetic resonance imaging (MRI). The anatomical features of SCs and positional abnormalities of the articular disc were initially evaluated using MRI. A second MRI examination was performed for 28/41 patients at 40-107 months (mean, 66 months) after the first MRI. The joint space, anteroposterior width of the condylar head (WiC), articular eminence angle (AEA), and visual analog scale of jaw pain (VAS) were assessed alongside the MRI examinations.

RESULTS

Most SCs were present in the anterosuperior and central condyle. Disc displacement was observed in 100% of 42 TMJs with SCs. Of the 29 joints in 28 patients, SCs in 19 joints resolved with time, whereas SCs in 10 joints persisted. A significant increase in the WiC and a significant decrease in AEA and VAS scores were observed on the second MRI scan.

CONCLUSIONS

SCs tended to form in the anterosuperior and central parts of the condyle, where mechanical loading was likely to be applied. SCs are strongly associated with articular disc displacement. Two-thirds of SCs resolved over time, accompanied by resorption and osteophytic deformation of the condyle. SC might not be an indicator for the start of surgical treatment, and nonsurgical treatment could improve the clinical symptoms of patients with SCs.

Temporomandibular joint articular disc position and shape in skeletal Class III

OBJECTIVE

To compare the position and shape of the temporomandibular joint (TMJ) articular disc among the sagittal and vertical skeletal patterns in Angle Class III, Class III subdivision malocclusion and normal occlusion. The null hypothesis was that there was no difference in disc position and shape in different (1) malocclusions and (2) skeletal patterns.

METHODS

This cross-sectional observational study evaluated 105 patients divided into 3 groups: Class III (33, 9.39 ± 1.96 years), Class III subdivision (45, 9.51 ± 1.59 years) and a normal occlusion (27, 10.24 ± 0.87 years) was included as healthy control. Severity of the maxilla-mandibular anteroposterior discrepancy and vertical facial pattern were determined using 2D cephalometry, and the position and shape of the articular discs were evaluated in magnetic resonance images. Statistical parametric and non-parametric tests and Kappa analysis for intra-observer and inter-observer assessment were used (p ≤ .05).

RESULTS

Significant between-group differences were found in articular disc position. In the normal occlusion group, all the articular discs were well positioned. In Class III and Class III subdivision, the discs were displaced in 30.3% and 12.2% of the TMJs, respectively. Sagittal and vertical skeletal patterns did not affect the findings significantly. The Class III subdivision malocclusion group is probably different from the other groups, showing 97.7% of biconcave discs in both TMJs.

CONCLUSION

The longitudinal follow-up of this sample becomes relevant as the two groups with malocclusion in the pre-peak phase of pubertal growth showed differences in the prevalence of displacement and form of the articular disc, with no association with their vertical facial characteristics.

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.

Temporomandibular joints disorders (TMDs) prevalence and their relation to anxiety in dental students

Background: Temporomandibular joint disorders (TMDs) are very common disorders affecting the population and causing pain. Researchers have reported a high prevalence of TMDs among university students due to increased distress. The aims of this study were to determine the frequency of TMDs in Umm al-Qura University (UQU) dental students using the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD), and to examine the relationship between anxiety, bruxism, and TMDs among those students. Methods: The DC/TMD pain screener questionnaire was completed by dental students. Students who reported TMD pain or had at least one positive TMD symptom were invited to the dental clinic for a full TMJ evaluation. History of bruxism was documented and an ultra-brief tool for detecting anxiety and depression (Patient Health Questionnaire-4 PHQ) was completed by all students. Results: A total of 240 students responded to the TMD pain screener in which 119 reported at least one TMJ symptom. Only 93 dental students presented to clinical examination in which 64.5% (n=60) of them had temporomandibular joint disorders. Disc displacement with reduction and local myalgia (38.7% & 32.25%, respectively) were the most frequent diagnosis. A total of 29% (n=27) of students had more than one diagnosis. Overall, 41 participants (44.09%) reported a positive response to the anxiety scale and (n=38) 40% of participants reported parafunctional habits. Both the history of bruxism and anxiety were significantly related to TMDs (P=0.0002) and also significantly higher in women of higher academic years (P≤0.01). Conclusions: This study found a high prevalence of TMDs among UQU dental students. Disc displacement with reduction was the most prevalent disorder. Bruxism and anxiety were associated with painful TMDs.

Automated segmentation of articular disc of the temporomandibular joint on magnetic resonance images using deep learning

Temporomandibular disorders are typically accompanied by a number of clinical manifestations that involve pain and dysfunction of the masticatory muscles and temporomandibular joint. The most important subgroup of articular abnormalities in patients with temporomandibular disorders includes patients with different forms of articular disc displacement and deformation. Here, we propose a fully automated articular disc detection and segmentation system to support the diagnosis of temporomandibular disorder on magnetic resonance imaging. This system uses deep learning-based semantic segmentation approaches. The study included a total of 217 magnetic resonance images from 10 patients with anterior displacement of the articular disc and 10 healthy control subjects with normal articular discs. These images were used to evaluate three deep learning-based semantic segmentation approaches: our proposed convolutional neural network encoder-decoder named 3DiscNet (Detection for Displaced articular DISC using convolutional neural NETwork), U-Net, and SegNet-Basic. Of the three algorithms, 3DiscNet and SegNet-Basic showed comparably good metrics (Dice coefficient, sensitivity, and positive predictive value). This study provides a proof-of-concept for a fully automated deep learning-based segmentation methodology for articular discs on magnetic resonance images, and obtained promising initial results, indicating that the method could potentially be used in clinical practice for the assessment of temporomandibular disorders.

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.

Temporomandibular disorders among medical students in China: prevalence, biological and psychological risk factors

BACKGROUND

The purpose of the present study is to evaluate the prevalence of temporomandibular disorders (TMD) and their associated biological and psychological factors in Chinese university students.

METHODS

A total of 754 students were included from Zunyi Medical University, each participant completed questionnaires and clinical examinations according to the Diagnostic Criteria for Temporomandibular Disorders.

RESULTS

The overall prevalence of TMD was 31.7% among medical students. Subjects with TMD had a high prevalence of bruxism, empty chewing, unilateral chewing, chewing gum, anterior teeth overbite, anterior teeth overjet, depression, anxiety, and sleep disturbance. Moreover, sleep bruxism, empty chewing, unilateral chewing, anterior teeth overbite, depression, and anxiety were the strongest risk factors for TMD.

CONCLUSIONS

Individuals with TMD have a high prevalence of psychological distress and oral parafunctional habits. Except for the psychological factors associated with TMD, bruxism, abnormal chewing, and malocclusion also shared similar risks for TMD.

Internet-based treatment for adolescents with symptomatic temporomandibular joint disc displacement with reduction. A randomized controlled clinical trial

OBJECTIVE

To evaluate treatment outcome of a jaw exercise (JE) intervention program combined with an information/counselling program (IC) vs. information/counselling alone.

MATERIALS AND METHODS

A clinical sample of 83 adolescents, experiencing painful clicking or catching/locking of the jaw, and diagnosed with symptomatic disc displacement with reduction according to RDC/TMD, were randomly assigned to JE/IC or IC program. Both programs were internet-delivered. The adolescents were examined clinically at baseline, at a 2-month mid-evaluation, and at 4months posttreatment by examiners blinded to which programs the adolescents were assigned to.

RESULTS

The JE/IC group showed significantly more improvements of painful catching/locking (p = .017), eating ability (p = .006) and of their jaw function limitation (p = .026) compared to the IC group. Significantly more adolescents in the JE/IC group also reported a ≥50% improvement of the catching/locking of the jaw with pain (p = .024) and for eating ability (p = .034) based on a severity index. Treatment method credibility and satisfaction were also significantly higher in the JE/IC group.

CONCLUSION

The internet-delivered JE/IC program showed a better outcome compared to IC alone. The former is thus a feasible and cost-effective treatment for adolescents with symptomatic disc displacement with reduction.

Histopathology of the temporomandibular joint disc: Findings in 30 samples from joints with degenerative disease

Aim

The aim of this study is to show the anatomical and histological features of the displaced temporomandibular joint (TMJ) disc in joints with degenerative disease.

Methods

This study was performed on a total of 30 TMJ discs extracted from 22 patients, who underwent surgical discectomy after failure of conservative non‐surgical treatment regimens to control pain and/or limited range of motion. All joints had imaging signs of an anteriorized disc position and degenerative joint disease. Samples of the extracted discs were stored in formalin, cut into 3 micron‐thick sections imbedded in paraffin and processed with hematoxylin‐eosin.

Result

All the samples present irreversible morphologic and histological alterations. The macroscopical evaluation showed that 14 discs were worn and fragmented in several parts, and one disc was perforated. Morphological alterations with deformation and degenerative signs were shown in all discs, which were all severely worn and compromised. Histologically, various alterations were found, such as pre‐fibrous sclerosis with myxoid degeneration and collagen deposits (N = 25), an increase in fibro‐hyaline and fibrous tissues, with loss of elasticity (N = 25), scattered calcifications (N = 15), and synovial inflammation with microvascular proliferation and increased cellularity, presence of lymphocytes, histiocytes and plasma cells (N = 18). After the intervention, all patients reported decreased pain levels and showed improved function at 6 months.

Conclusion

These observations suggest that degenerative joint disease is accompanied by a anteriorized discs featuring abnormal macroscopical and histological changes. From a clinical viewpoint, this may suggest that, when treatment escalation leads to consider TMJ surgery, total discectomy is the most reasonable approach.

Temporomandibular joint morphology in Korean using cone-beam computed tomography: influence of age and gender

OBJECTIVES

The purpose of this study was to investigate the condylar morphology and position of Koreans using cone-beam computed tomography (CBCT) images. Analyzing the mean values of this study with reference to left and right sides, gender, and age will help to understand the size of the condyle and glenoid fossa, condylar morphology, and temporomandibular joint (TMJ) symmetry for establishing the standard temporomandibular joint structures of Koreans and then design the standard temporomandibular joint prosthesis for Koreans.

RESULTS

There was no significant result in the condyle size, condyle axis angle, joint space, fossa depth, and mandibular body size between the left and right sides (p > 0.05). On the other hand, the mediolateral width of the condyle and mandibular body size show significantly different with the gender (P < 0.05). Also, significant differences were found in condyle size, joint space, fossa depth, and mandibular body size according to age groups (p < 0.05).

CONCLUSIONS

Condylar position and morphology vary according to side, age, and gender. The results of this study are expected to help in customizing a treatment for the patients who need TMJ reconstruction by predicting the TMJ morphology according to age and gender and design the standard temporomandibular joint prosthesis for the Koreans.

Transitioning to chronic temporomandibular disorder pain: A combination of patient vulnerabilities and iatrogenesis

Background

Based on a variety of studies conducted in recent years, some of the factors that might contribute to the negative treatment responses of some TMD patients have been elucidated.

Methods

This paper describes known vulnerability factors that make individuals susceptible to developing temporomandibular disorders (TMDs), as well as those that contribute to the perpetuation of such problems. In addition, the topic of iatrogenesis is discussed as a major contributor to the negative outcomes that can be seen in this field.

Results

At the patient level, anatomical, psychosocial and genetic factors may contribute to individual vulnerability. The anatomy and pathophysiology of muscles, joints, disc and nerves may all be involved in predisposing to TMD symptoms, especially when the patients have pain elsewhere in the body. Among the psychosocial factors, some features may be elucidated by the DC/TMD axis II, while others (eg illness behaviour, Munchausen syndrome, lack of acceptance of non‐mechanical approaches) require careful evaluation by trained clinicians. Genetic predisposition to first onset TMDs and to chronification of symptoms has been identified for individuals with certain psychological traits, presence of comorbid conditions and certain abnormal clinical manifestations. Regarding iatrogenesis, sins of omission may influence the clinical picture, with the main ones being misdiagnosis and undertreatment. Joint repositioning strategies, occlusal modifications, abuse of oral appliances, use of diagnostic technologies, nocebo effect and complications with intracapsular treatments are the most frequent sins of commission that may contribute to chronification of TMDs. The patients who present with massive occlusal and jaw repositioning changes combined with persistent severe orofacial pain are not a rarity within TMD and orofacial pain canters; these patients are the most difficult ones to manage because of this horrific combination of negative factors.

Conclusions

The information presented in this paper will help clinicians to understand better why some individuals develop temporomandibular disorders, why some of them will progress to becoming chronic patients, and what the appropriate responses may be.

Is the Temporomandibular Joints' Reciprocal Clicking Related to the Morphology and Position of the Mandible, as Well as to the Sagittal Position of Lower Incisors?-A Case-Control Study

The number of patients diagnosed with temporomandibular joint (TMJ) internal derangements, who are seeking orthodontic treatment, is increasing. The aim of the study was to assess the relationship between the presence of TMJ reciprocal clicking and the morphology and position of the mandible, and position of lower incisors, examined on the lateral cephalograms. Fifty patients diagnosed with reciprocal clicking in at least one of the TMJs and 55 patients with no symptoms of TMJ dysfunction were included in the study. Cephalometric analysis was used for the assessment of: skeletal class, sagittal and vertical position of the mandible, angle of the mandible, inclination of the mandibular ramus and the mandibular corpus, as well as for the assessment of the position of the mandibular incisors. The statistical significance level was set at p = 0.05. There were no statistically significant differences between the examined groups regarding the sagittal and vertical position of the mandible, as well as regarding the sagittal position of the mandibular incisors. Presence of TMJ reciprocal clicking is not associated with the position and the morphology of the mandible, as well as with the sagittal position of the mandibular incisors. Patients with early stages of TMJ internal derangements do not present any significant changes in Cephalometrics. Patients diagnosed with TMJ internal derangements before orthodontic treatment require an interdisciplinary approach to the treatment, including physiotherapy.

Application of auriculotemporal nerve block and dextrose prolotherapy in exercise therapy of TMJ closed lock in adolescents and young adults

Background

Temporomandibular joint (TMJ) ‘closed lock’ is a clinical condition causing TMJ pain and limited mouth opening (painful locking). Recent studies suggest an increasing prevalence of degenerative joint disease associated with the onset of TMJ closed lock in adolescents and young adults. Early interventions are recommended, but the curative effect of standard therapies remains controversial. In this retrospective study, an alternative method of non-surgical treatment of TMJ closed lock is presented, and its long-term efficacy has been observed.

Methods

Forty adolescents and young adults, aged 16 to 30 years old, with distinct combination of symptoms of TMJ closed lock, were enrolled. Patients received anesthetic blockages of the auriculotemporal nerve, then performed mandibular condylar movement exercise for 10 min, and subsequently received hypertonic dextrose prolotherapy in retro-discal area of TMJ. Clinical assessments at baseline and at follow-up (2 weeks, 2 months, 6 months, and 5 years) included intensity and frequency of TMJ pain, mandibular range of motion, TMJ sounds, and impairment of chewing.

Results

Cone beam CT images of the TMJs revealed joint space changes in all patients and degenerative bone changes in 20% (8/40) of the patients. The patients were diagnosed as having disc displacement without reduction with limited opening. Successful reduction of displaced disc had been achieved in the treatment. And pain at rest and pain on mastication had substantially decreased in all patients and mandibular function and mouth opening had significantly improved since 2 weeks’ follow-up. The overall success rate kept at a high level of 97.5% (39/40) at 6 months and 5 years’ follow-up.

Conclusions

The technique combining mandibular condylar movement exercise with auriculotemporal nerve block and dextrose prolotherapy is straightforward to perform, inexpensive and satisfactory to young patients with TMJ closed lock.

Temporomandibular disorder severity and diagnostic groups: Their associations with sleep quality and impairments

OBJECTIVES

This study evaluated the impact of TMD severity on sleep quality and established the associations between TMD diagnostic groups/pain subtypes and sleep impairments.

METHODS

A total of 1151 patients from a tertiary Dental Hospital were screened for eligibility. Consenting subjects who met the inclusion criteria were directed to complete a general/health questionnaire, the Fonseca Anamnestic Index (FAI), Diagnostic Criteria for Temporomandibular disorders (DC/TMD) Symptom Questionnaire, and Pittsburgh Sleep Quality Index (PSQI) at their intake visit. Patients who screened positive for TMDs with the FAI were subjected to a protocolized physical examination and TMD diagnostic groups/subtypes were subsequently derived based on the DC/TMD "diagnostic tree" and algorithms. Statistical analyses were conducted using non-parametric methods and logistic regression (α = 0.05).

RESULTS

The final sample consisted of 845 subjects with TMDs and 116 TMD-free controls. The mean age of the TMD and TMD-free subjects were 33.17 ± 13.55 and 31.66 ± 9.50 years. Subjects with severe and moderate TMDs had significantly greater global PSQI scores than those with mild and no TMDs (p < 0.001). Those with pain-related, intra-articular, and combined TMDs reported significantly poorer sleep quality than those with no TMDs (p < 0.001). Moreover, subjects with myalgia and myalgia plus arthralgia presented significantly greater sleep impairments than their counterparts with intra-articular disorders (p < 0.001). Multivariate logistic regression indicated that pain-related (OR = 3.23; CI = 1.69-6.14) and intra-articular TMDs (OR = 1.91; CI = 1.15-3.16) were most related to poor sleep.

CONCLUSIONS

Sleep quality worsened with increasing TMD severity and the presence of painful and intra-articular TMDs increased the likelihood of poor sleep.

Prevalence of temporomandibular joint disorders: a systematic review and meta-analysis

OBJECTIVES

The aim of this systematic review was to evaluate the prevalence of temporomandibular joint disorders (TMJD) among the general population.

MATERIALS AND METHODS

Five main electronic databases and three grey literature were searched to identify observational studies in which TMJD was diagnosed using the research diagnostic criteria (RDC/TMD) or diagnostic criteria (DC/TMD). The studies were blindly selected by two reviewers based on eligibility criteria. Risk of bias (RoB) was assessed using the Joanna Briggs Institute Critical Appraisal Checklist, and the "R" Statistics software was used to perform meta-analyses.

RESULTS

From 2741 articles, 21 were included. Ten studies were judged at low RoB, seven at moderate, and four at high. The TMJD investigated were as follows: arthralgia, disk displacement (DDs) with reduction (DDwR), DDwR with intermittent locking, DDs without reduction (DDwoR) with limited opening, DDwoR without limited opening, degenerative joint disease (DJD), osteoarthritis, osteoarthrosis, and subluxation. The main results from prevalence overall meta-analyses for adults/elderly are as follows: TMJD (31.1%), DDs (19.1%), and DJD (9.8%). Furthermore, for children/adolescents are as follows: TMJD (11.3%), DDs (8.3%), and DJD (0.4%). Considering the individual diagnosis meta-analyses, the most prevalent TMJD is DDwR for adults/elderly (25.9%) and children/adolescents (7.4%).

CONCLUSIONS

The overall prevalence of TMJD was approximately 31% for adults/elderly and 11% for children/adolescents, and the most prevalent TMJD was DDwR.

CLINICAL RELEVANCE

Knowledge about the frequency of TMJD can encourage dentists to consider appropriate strategies for early and correct diagnosis and, if need be, correct management.

Low skeletal bone mineral density as a potential aetiological factor towards idiopathic condylar resorption

The aim of this study was to investigate the contributing factor of impaired skeletal quality in the pathogenesis of idiopathic condylar resorption (ICR). One hundred and twenty-six patients with MRI-confirmed ICR and 596 patients with disc displacement (DD) without a diminished condyle, of both sexes, were included. Dental examinations and retrospective surveys regarding temporomandibular joint symptoms and progression of maxillofacial deformities were conducted. Skeletal bone mineral density (BMD) was measured by dual energy X-ray absorptiometry (DXA) and converted to T-scores and Z-scores. Results showed that ICR patients had a smaller overbite (1.56±3.3 vs 3.05±2.0mm), larger overjet (4.9±2.4 vs 3.5±1.9mm), larger range of mouth opening (36.5±6.7 vs 33.6±7.1mm), and higher rates of anterior open bite and mandibular retrusion compared to DD patients (all P<0.001). ICR was associated with an increased probability of low skeletal BMD at chronological age in females (P=0.020) but not in males (P=0.095). This study indicates that reduced BMD may predispose females to an exacerbated condylar resorption process in addition to increased joint loading initiated from DD.

Association Between -1607 1G/2G Polymorphism of MMP1 and Temporomandibular Joint Anterior Disc Displacement with Reduction

Anterior disc displacement with reduction (DDWR) is considered one of the most common disorders within the temporomandibular joint (TMJ), with a prevalence of 41% in adults. Matrix metalloproteinases play an important role in the degradation of the TMJ and the matrix metalloproteinase 1 (MMP1) 1607 1G/2G polymorphism increases the local expression of MMP1 thus leading to accelerated degradation of the extracellular matrix. The objective of this study was to evaluate the association between the 1607 1G/2G polymorphism of MMP1 gene and DDWR in a group of Mexican individuals from western Mexico. A total of 67 unrelated individuals, between the ages of 18 and 36 years, of both genders, were included in this study. Study participants with DDWR were required to meet the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD), while a second control group of 90 individuals without DDWR were also included. Both groups were required to have paternal and maternal ancestry (grandparents) of the same geographic and ethnic region. Genotypes were determined using the nested PCR technique. The 1G/2G polymorphism was found in 68.7%, followed by 2G/2G in 25.4% and 1G/1G in 6.0% of the cases group. While the prevalence in the control group was 55.5% for the 1G/2G polymorphism, 26.6% for 1G/1G and 17.7% for 2G/2G. An association was found between the 2G allele of the 1607 1G/2G polymorphism of MMP1 gene and the presence of DDWR in the patients of western Mexico.

Temporomandibular Joints' Morphology and Osteoarthritic Changes in Cone-Beam Computed Tomography Images in Patients with and without Reciprocal Clicking-A Case Control Study

Background: Patients referred for orthodontic treatment often present symptoms of temporomandibular joints’ disorders (TMD), predominantly clicking. The objective was to analyze the morphology of the temporomandibular joints in cone-beam computed tomography (CBCT) images based on the presence of reciprocal clicking before orthodontic treatment. Methods: 105 participants took part in the study. 210 temporomandibular joints (TMJs) were allocated into one of two groups regarding the presence of reciprocal clicking. Morphology of condyle’s head, glenoid fossa, and articular eminence as well as condylar head position in the glenoid fossa and osteoarthritic changes in the area of the condylar head were examined for each TMJ in the CBCT images. Statistical analysis was performed with STATISTICA version 12.0. The following tests were performed: U-Mann Whitney, Kruskal-Wallis, t-Student, and chi-square. The statistical significance level was p = 0.05 for all the measurements included. Results: Significantly smaller condylar A-P dimension (p = 0.040) characterized temporomandibular joints with reciprocal clicking. Condyles were substantially more often positioned posteriorly (p = 0.043) and were significantly more often accompanied by subcortical cysts and pathologic osteoarthritic bone changes (p < 0.001). Conclusions: The early stages of internal derangements stay with alterations in morphology and position of TMJs as well as with the presence of osteoarthritic changes.

A rat model for inducing temporomandibular anterior disc displacement experimentally

The aim of this study was to establish an experimental rat model of temporomandibular joint (TMJ) anterior disc displacement (ADD). A pilot study was conducted to determine the most appropriate surgical protocol. In the main experiment, 40 rats were used. Twenty-four rats were subjected to ADD in the right TMJ, and subsequently thereafter six, nine, and nine rats were sacrificed at 1, 4, and 8 weeks, respectively, for gross evaluation. Twelve rats that underwent a sham operation were equally divided and sacrificed at each of the above time points. Four non-treated control rats were sacrificed at the beginning of the study. TMJ blocks were harvested for radiological and histological assessment. Gross examination showed that 14 rats in the ADD group (58.3%) had anterior displacement of the TMJ disc. In the ADD joints, posterior condylar cartilage thickness decreased during the follow-up period; however, there was no significant difference between the sham-treated and ADD joints, or among the follow-up time points (P > 0.05). The anterior condylar cartilage exhibited obvious qualitative alterations. Radiologic signs of osteoarthrosis appeared after ADD surgery, but this became attenuated with time. The model investigated in this study successfully induced ADD in rats, and should be useful for assessment of progressive changes in the TMJ following ADD.

Are vocalists prone to temporomandibular disorders?

BACKGROUND

As vocalists demand high physical strains of the masticatory system, singing is frequently mentioned as a risk factor for temporomandibular disorders (TMDs).

OBJECTIVES

This study investigated whether vocalists report a higher prevalence of two types of TMDs (viz., TMD pain and temporomandibular joint sounds) compared with instrumentalists who do not load their masticatory system while performing. In addition, we examined which risk indicators are associated with the presence of these TMDs among musicians.

METHODS

A total of 1470 musicians from 50 different music ensembles completed a questionnaire. Of these musicians, 306 were vocalists (mean age ± SD 37.5 ± 17.7 years; 63.9% female) and 209 musicians enrolled the control group (mean age ± SD 42.7 ± 18.0 years; 40.7% female).

RESULTS

The prevalence of self-reported TMD pain among vocalists was 21.9%, as compared to 12.0% in the control group. 20.0% of the vocalists reported TMJ sounds versus 15.1% of the controls. The multiple regression models indicated that being a vocalist was not a risk indicator for the presence of self-reported TMD pain nor for self-reported TMJ sounds. Instead, it appeared that the report of TMD pain among musicians was positively associated with female gender, next to the level of physical workload, depicted as frequency of oral behaviours and the hours of daily practice. Musicians' report of TMJ sounds was associated with oral behaviours.

CONCLUSION

This study shows that singing is not associated with the reports of TMD pain and TMJ sounds, after adjusting for potentially confounding variables included in the models.