Temporomandibular Joint Disc Displacement Research Articles

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

ObjectiveTo 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.MethodsThis 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.ResultsDuring 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.ConclusionCompared 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.

The Effect of Temporomandibular Joint Disc Displacement Type on Jaw Function Limitation

Aim: Temporomandibular joint disorder (TMD) present symptoms such as pain, swelling, clicking or crepitating sounds, limitations or blockages in jaw movements, and may even affect simple functions such as eating and speaking. This study aims to evaluate the impact of disc displacement type on jaw function in patients with TMD who suffer from disc displacement. Material and Methods: This cohort study was conducted on patients with temporomandibular joint (TMJ) disc displacement. The independent variable was the type of disc displacement. The outcome variable was the scores on the Jaw Functional Limitation Scale-20 (JFLS-20). The covariates included the patient's age and pain score. Data collection methods were carried out using the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) guidelines and the JFLS-20 questionnaire, with pain levels also assessed using a visual analog scale. Data analysis was performed using ANOVA and Pearson Correlation tests, with a significance level set at 0.05. Results: The study groups were formed by including 72 patients with disc displacement, while the control group was formed by including 28 healthy volunteers. The control group had lower JFLS-20 scores than the disc displacement groups(p&lt;0.05). Although there was no statistically significant difference in JLFS-20 scores between the disc displacement groups, disc displacement with reduction group had significantly lower pain scores than both disc displacement without reduction groups(p&lt;0.05). Conclusion: It was observed that individuals with disc displacement experience restricted jaw functions, and this limitation is not affected differently by the various subtypes of disc displacement.

Evaluating the Impact of Various Treatment Modalities on the Chewing Efficiency of Anterior Disc Displacements of Temporomandibular Joint Disorder Cases: A Comparative Study

Abstract Aim: Internal disc displacement of the temporomandibular joint (TMJ) is identified by an anomaly between the condylar-disc assembly, which, in many cases, may lead to discomfort and malfunction of the chewing function. The study’s objective was to assess the effects of four distinct treatment approaches on temporomandibular disorder cases with anterior disc displacements focusing on their chewing efficiency. Materials and Methods: One hundred participants suffering from reducible TMJ disc displacement were selected for enrollment in the study. Subjects were divided equally into four groups: group I patients were treated with behavioral therapy; group II patients were treated with low-level laser therapy (LLLT); group III patients were treated with anterior repositioning splints; and group IV patients were treated with flat plane splints. Chewing efficiency was assessed utilizing the fractional sieving method and a synthetic food substitute was created using silicon impression material. The statistical analysis encompassed comparisons of chewing efficiency between groups and between baseline and posttreatment within each group, employing analysis of variance (ANOVA) and paired t tests, respectively. Results: Using the paired t test, a significant difference in chewing efficiency values as expressed by the median particle size was observed between the baseline and 6-month values in all groups (P &lt; 0.05), except for group I where no significant change was noted over the 6 months (P &gt; 0.05). The one-way ANOVA test revealed a statistically significant difference among groups following therapies (P ˂ 0.05). The post hoc Tukey test was employed for pairwise comparisons and revealed statistically significant variances in the main values of chewing efficiency among all groups at a 95% confidence level (P ˂ 0.05). Conclusion: The study’s results suggest that occlusal splints and LLLT are more effective in improving chewing efficiency than behavioral interventions.

A three-dimensional imaging study of the effect of anterior disc displacement on the bony structural relationship of the temporomandibular joint

Objective: To investigate the correlation between the osseous structure of temporomandibular joint (TMJ) and three different status of anterior disc location, so that it could guide the clinical diagnosis further. Methods: Fifty-two patients [46 females and 6 males, with an age of (27.8±8.3) years] who treated with MRI and cone beam CT, were recruited from the Temporomandibular Joint Specialist Clinic, The First Affiliated Hospital of Xinjiang Medical University, between March 2018 to December 2021. According to the radiographic findings of the level of anterior disc displacement (ADD) in TMJ, patients were divided into three groups: normal articular disc position (NADP, n=28 TMJs), anterior disc displacement with reduction (ADDWR, n=28 TMJs), and anterior disc displacement without reduction (ADDWoR, n=28 TMJs). In the light of the reconstructed three-dimensional model, ten representative morphological parameters including condylar volume (CV), condylar superficial area (CSA), fossa volume (FV), fossa superficial area (FSA), the proportion of the condylar volume in the articular fossa (CV%), the proportion of the condylar superficial area in the articular fossa (CSA%), superior joint space (SJS), anterior joint space (AJS), posterior joint space (PJS), and medial joint space (MJS), were measured respectively under one-way analysis of variance (ANOVA), Kruskal-Wallis Htest and receiver operator characteristic curve(ROC curve) analyses. Results: CV and CSA values varied significantly in the pathological progression from normal location to irreversible anterior displacement in TMJ. For CV value, NADP group [(1 834.90±667.67) mm3]>ADDWR group [(1 747.34±369.42) mm3]>ADDWoR group [(1 256.29±418.27) mm3] [t=4.31, P(NADP-ADDWoR)<0.001; t=3.66, P(ADDWR-ADDWoR)<0.001], for CSA value, NADP group [(859.27±216.01) mm2]>ADDWR group [(838.23±118.82) mm2]>ADDWoR group [(669.14±150.26) mm2] [t=4.27, P(NADP-ADDWoR)<0.001; t=3.80, P(ADDWR-ADDWoR)<0.001]. The difference of SJS value in NADP group [(2.22±0.88) mm], ADDWR group [(1.94±0.64) mm] and ADDWoR group [(1.45±0.57) mm], was statistically significant [t=4.11, P(NADP-ADDWoR)<0.001; t=2.63, P(ADDWR-ADDWoR)=0.010]. The results of MJS in NADP group [(5.03±1.41) mm], ADDWR group [(3.86±1.32) mm], and ADDWoR group [(4.91±1.65) mm] were significantly different [t=3.00, P(NADP-ADDWR)=0.004; t=2.63, P(ADDWR-ADDWoR)=0.009]. As calculated by the ROC curve analysis, CV, CSA and SJS showed that (AUCCV=0.77, AUCCSA=0.76; AUCSJS=0.76) for the NADP and ADDWoR groups, and (AUCCV=0.80; AUCCSA=0.80; AUCSJS=0.72) for the ADDWR and ADDWoR groups. While the diagnostic accuracy of MJS for the comparison in NADP versus ADDWR and ADDWR versus ADDWoR was respectively AUC(NADP-ADDWR)=0.73, and AUC(ADDWR-ADDWoR)=0.69. Conclusions: CV, CSA, SJS, and MJS were significantly associated with the different disc displacement status, and the condyle in TMJ ADD exhibited three-dimensionally altered dimensions. They could be considered as promising biometric markers to diagnose the ADD status.

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.

Effectiveness of anterior repositioning splint versus other occlusal splints in the management of temporomandibular joint disc displacement with reduction: A meta-analysis.

Disc displacement with reduction (DDwR) is among the common disc disorders of temporomandibular joint (TMJ), which can be managed conservatively by splint therapy. Anterior repositioning splint (ARS) is the most commonly prescribed splint by dental practitioners, but not getting a normal disc-condyle relationship always and other side effects lead to need of comparing with other occlusal splints. This review will help in informed decision-making by clinicians in choosing an appropriate splint type for patients. The aim is to compare the effectiveness of ARS in the management of DDwR with other occlusal splints for TMJ and muscle pain, TMJ noise, any adverse effects, regaining normal disc-condyle relationship. We followed published protocol in the International prospective register of systematic reviews. Databases were searched till May 2023 using different search strategies as per the database. Title and abstract screening, followed by full-text screening and data extraction with risk of bias, was done by two independent reviewers in Covidence. Outcomes were reported as risk ratio (RR) or mean difference (MD) for dichotomous or continuous outcomes, respectively, using RevMan 5.4 (Review Manager 5.4) software. We used a random effect model for statistical analysis. Certainty of evidence was assessed using the Grading of Recommendation, Assessment, Development, and Evaluation Guideline Development Tool (GRADEpro GDT) software. A total of 1145 reports were found from a database search. After screening, four studies were included for systematic reviews. Other occlusal splints reported were sagittal vertical extrusion device and mandibular ARS, full hard stabilization splint of canine or centric stabilization type. Data of only two studies could be used for meta-analysis having 30 participants received ARS and 40 received other occlusal splints. We did not find evidence of any difference between ARS and other occlusal splints for TMJ clicking in short term (RR 1.25, 95% confidence interval [CI] 0.91-1.72) but a small difference in favor of other occlusal splint in long term (RR 2.40, 95% CI 1.04-5.55). No evidence of any difference was found between both treatments for TMJ pain in short term (MD-5.68, 95% CI-17.31-5.95) and long term (MD 0.00, 95% CI-2.86-2.86) and muscle pain in short term. The certainty of evidence for comparison of two treatments for different outcomes was of low or very low level. Evidence is uncertain that other occlusal splints reduced TMJ clicking slightly in comparison to ARS. For the remaining outcomes, no evidence of any difference was found between the two splints and it may be biased due to selection bias, inadequate blinding of participants, and outcome assessor.

Severity of Temporomandibular Joint Disc Displacement and Generalized Joint Hypermobility in Growing Patients: A Cross-Sectional Magnetic Resonance Image Study

Background: This study aimed to investigate the association between the internal derangement of the temporomandibular joint (TMJ), in particular the severity of disc displacement (DD), and the presence of generalized joint hypermobility (GJH) in growing patients evaluated on magnetic resonance images (MRIs). The study also investigated the relationship between the stages of DD severity and age. Methods: This cross-sectional study has been conducted on a pre-orthodontic population (8–16 years). The GJH was assessed with the Beighton test (cutoff ≥ 4) and the final sample of 56 patients was divided into two groups: a study group, 30 subjects with GJH, and a control group, 26 subjects without GJH. The disc position was evaluated on MRI and the severity of DD was classified in four stages. Pearson’s χ2 Test was performed for the analysis of the statistical correlation. Results: A statistically significant relationship between GJH and disc position was found, in particular, a disc displacement with reduction (DDwR) and DD severity. A positive association also emerged between the severity of DD and age, that increased with increasing age. Conclusions: The research results suggest that there is an association between the presence of generalized joint hypermobility (GJH) and disc displacement (DD) in growing patients. Growing patients with GJH showed a higher severity of DD. In older patients, greater severity of DD was evident, suggesting that this condition may worsen with age during growth.

Management of traumatic temporomandibular joint ankylosis: a perspective

Traumatic injuries to the temporomandibular joint (TMJ) was the most common cause of TMJ ankylosis (85%), while sagittal fracture of the mandibular condyle was identified as the high risk fracture pattern. TMJ disc displacement is one of the prerequisite factors of TMJ ankylosis. The severe damage and close contacts of both the articular surface of glenoid fossa and condyle were also crucial pathogenic factors in the development of TMJ ankylosis. The mechanism and development of TMJ ankylosis may be similar to hypertrophic non-union, and the persistence of radiolucent zone within the ankylotic callus governs the clinical and pathological process of TMJ ankylosis. In type Ⅰ traumatic TMJ ankylosis, repositioning of the displaced disk is required, while the preservation of pseudo-joint is essential in the management of the type Ⅱ traumatic TMJ ankylosis. Nevertheless, the rate of TMJ reankylosis still remains high. Higher rate of TMJ reankylosis was observed in paediatric population, bilateral involvement of TMJ ankylosis, and in cases with reconstruction of mandibular condyle with coronoid process.

Efficacy of Digital Occlusal Splint Technology in the Treatment of Irreducible Anterior Displacement of Temporomandibular Joint Disc

This study investigates the efficacy of digital occlusal splint technology in treating irreducible anterior displacement of the temporomandibular joint (TMJ) disc and assesses its impact on clinical symptoms and TMJ function. A total of 36 patients treated for irreducible anterior displacement of the TMJ disc at our hospital from January to December 2022 were enrolled and randomized either into the digital occlusal splint group (digital group) or the traditional occlusal splint group (traditional group), with 18 patients in each group. The treatment duration for all patients was 12 weeks. Clinical adjustment time for occlusion was compared between the two groups. The Visual Analog Scale (VAS) recorded and evaluated pain intensity and patient comfort at initial wear, 1 week, and 4 weeks after splint usage. Maximum active mouth opening was measured before treatment and at 1, 4, 8, and 12 weeks post-treatment. The Fricton TMJ Dysfunction Index evaluated clinical efficacy based on parameters such as mandibular movement, joint noise, joint palpation, muscle palpation, dysfunction index, muscle tenderness index, and joint dysfunction index. Patient satisfaction with treatment was compared between the two groups. The clinical adjustment time for the digital occlusal splint was significantly shorter than that for the traditional occlusal splint (P &lt; 0.05). At 4 weeks, the digital group exhibited significantly lower pain scores than the traditional group (P &lt; 0.05). At 1 and 4 weeks, the digital group demonstrated significantly better comfort scores than the traditional group (P &lt; 0.05). There was no significant difference in maximum active mouth opening between the two groups before treatment and at 1 week after treatment (P &gt; 0.05). However, at 4, 8, and 12 weeks, the digital group displayed significantly greater maximum active mouth opening than the traditional group (P &lt; 0.05). The Fricton indices for the digital group were significantly lower than those for the traditional group after treatment (P &lt; 0.05). The patient satisfaction survey revealed a 100% satisfaction rate for the digital group and 88.9% for the traditional group (P &lt; 0.05). The application of digital occlusal splint technology in treating irreducible anterior displacement of the TMJ disc demonstrates excellent efficacy. It effectively shortens clinical adjustment time for the splint and significantly improves clinical symptoms and TMJ function in patients. This technology is worth promoting in clinical practice.

Application of modified articular disc anchorage in treating the perforation and rupture of temporomandibular joint disc.

This study aimed to use modified articular disc anchorage in treating old irreducible temporomandibular joint (TMJ) disc displacement with perforation and rupture, as well as to explore its efficacy. A total of 31 patients (34 sides) with 47 TMJ disc perforations who underwent surgical treatment in the Affiliated Stomatolo-gical Hospital of Nanchang University from January 2018 to December 2021 were selected. According to the location of disc perforation, it has five types: posterior disc perforation (typeⅠ), anterior disc perforation (typeⅡ), lateral disc perforation (type Ⅲ), composite disc perforation, and destruction disc perforation. The modified methods of disc anchoring were divided into two types according to the location of the perforation. TypesⅠandⅢ disc perforation were trea-ted by posterior anchoring method. For posterior ancho-ring, a screw was implanted into the posterolateral side of the condylar neck, and the disc was fixed on the screw by horizontal mattress suture. TypeⅡdisc perforation and compo-site disc perforation combined typeⅡperforation were treated by anterior and posterior double-anchoring method. For anterior anchoring, anchor screws or holes were placed at the anterior edge of the condylar neck, and horizontal mattress suture was performed at the posterior edge of the anterior perforation with an anchor wire. The articular disc was then fixed on the anchor screws or holes. For the posterior anchoring method, it was the same as the previous one. Paired t test was used to analyze the visual analog scale (VAS), maximum interincisal opening (MIO), and TMJ disorder index (CMI) of the patient before surgery and 1, 3, and 6 months after surgery. Disk-condyle position relationship by magnetic resonance imaging and postoperative quality of life in postoperative were analyzed. The incidence of perforation was 41.2% (14/34) in typeⅠ, 11.8% (4/34) in typeⅡ, 8.8% (3/34) in typeⅢ, 29.4% (10/34) in composite type, and 8.8% (3/34) in destruction type. The VAS, MIO, and CMI at 3, 6 months after operation significantly improved compared with those before operation (P<0.05). The effective reduction rate of disc was 96.77% (30/31). The quality of life at 6 months after surgery was 47.22±2.13, and the rate of excellent evaluation was 96.4% (27/28). Modified articular disc anchorage achieves a good curative effect for treating temporomandibular joint disc perforation and rupture. Nevertheless, its long-term effect requires further observation.

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.

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.

RA.DI.CA. Splint Therapy in the Management of Temporomandibular Joint Displacement without Reduction.

The purpose of this study is to report clinical and instrumental changes after RA.DI.CA splint therapy for temporomandibular joint disc displacement without reduction. Subjects affected by disc dislocation without reduction were recruited between July 2020 and May 2022 based on inclusion and exclusion criteria and treated with RA.DI.CA. splints over a period of 6 months. Clinical data were collected at each phase of the study (T0, T1, T2). Magnetic resonance imaging and electrognathography data were recorded at the beginning (T0) and at the end (T2) of the study. ANOVA with post-hoc contrasts was performed to assess differences in outcome measures over time. The Wilcoxon test was used to evaluate changes in disc-condyle angle between before- and after-treatment MRI. A two-tailed value of p < 0.05 was regarded as significant. Ten patients completed the study. There were statistically significant differences over time for arthralgia, headache, neck pain, and mouth opening. Disc recapture and an improved quality of mandibular movement were recorded in 70% of subjects. The clinical and instrumental improvements are probably due to the orthopedic action of RA.DI.CA splint treatment, which allows for a greater degree of joint mobilization. The purpose of this therapy is to recover the disc position if possible and achieve an adequate joint functional adaptation that avoids the progression of the structural damage and the recurrence of symptoms.

Impact of Emotional Stress and Physiotherapy Treatment on Prognosis of Temporomandibular Joint Disc Displacement with Reduction - A Case Report

Impact of Emotional Stress and Physiotherapy Treatment on Prognosis of Temporomandibular Joint Disc Displacement with Reduction - A Case Report

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

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

The Asymmetry of the Mandible in Patients with Unilateral Temporomandibular Joint Disc Displacement Confirmed by Magnetic Resonance Imaging.

The study aimed to determine the relationship between the mandibular asymmetry index according to Kjellberg between patients with painful unilateral anterior disc displacement (DD) and asymptomatic volunteers without disc displacement. Vertical measurements were performed on a panoramic single-image radiograph, and the disc status was confirmed by magnetic resonance imaging (MRI). Two groups of subjects were retrospectively selected, 40 patients (the overall mean age was 35.5 years; 75% female) with temporomandibular disorder symptoms confirmed by RDC/TMD axis I and manual functional analysis. Unilateral DD was determined by MRI. A comparative group of asymptomatic volunteers (20 dental students with a mean age of 23.4 years; 72% female) had the physiological position of the disc determined by MRI. The vertical asymmetry of the condyle was determined by the method of Kjellberg et al. The symmetry of the gonial angle of the mandible was also measured. A comparison of the mean of the asymmetry index between patients (average 90.89±7.08%) and asymptomatic volunteers (mean 95.86±4.44%) showed a statistically significant difference (p=0.0029). There was no difference (p=0.088) in gonial angle symmetry between the patients (mean 96.48±2.96°) and the asymptomatic volunteers (mean 97.52±2.31°). The distribution of the presence of individual DD diagnoses (partial and total displacement with reduction, displacement without reduction) in patients diagnosed with asymmetry of the mandible was without statistical significance (p>0.05). This study actually points to the asymmetry of the mandible as a potential morphological risk of anterior DD.

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

ObjectiveTo 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 methodsPatients 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.ResultsThe 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).ConclusionThe exercise with recommendations showed better results, resolution of the click, and self-perception of the treatment effectiveness.Clinical relevanceThis 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 registerThis 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.

Transverse Malocclusions: Etiology, Development, Diagnosis and Treatment

Malocclusions that involve the transverse dimension are very common in the orthodontic office. They can be as simple as a crossbite of the posterior teeth or as severe as a Class III malocclusion with a mandibular asymmetry. Transverse malocclusions can vary from being a simple dento-alveolar problem to a more complex challenge as represented by a skeletal asymmetry that has developed after puberty and causing temporomandibular disorder (TMD) problems. In this review we shall address the most common types of transverse malocclusions and review their etiology and development. The most typical etiology of transverse anomalies will be discussed, and we will suggest diagnostic criteria to differentiate the individual malocclusions. We shall also introduce a frontal cephalometric analysis that relates to the anterior part of the face helping to differentiate between dento-alveolar and skeletal transverse malocclusions as well as determine the presence of dento-alveolar compensations. Furthermore, we shall suggest possible treatment approaches and the best timing of treatment for the most common types of transverse malocclusion. Finally, we shall present several cases with more unusual etiology including a case with mandibular asymmetry due to an anterior disc displacement of temporomandibular joint. A case with Class III malocclusion with mandibular overjet caused by maxillary stenosis will also be presented. Furthermore, we will show an example of a late developing mandibular asymmetry which is not an uncommon problem and document a case of excess mandibular growth with mandibular asymmetry and Class III malocclusion combined with posterior crossbite. This review will also address considerations that may affect the post treatment stability.

A Comparative Study of Temporomandibular Joints in Adults with Definite Sleep Bruxism on Magnetic Resonance Imaging and Cone-Beam Computer Tomography Images.

The aim was to study the imaging characteristics of the temporomandibular joint (TMJ) of definite sleep bruxers through magnetic resonance imaging (MRI) and cone-beam computer tomography (CBCT). Nineteen definite sleep bruxers diagnosed by polysomnography and twenty asymptomatic non-bruxers matched by age, gender, and education level participated in this study. After obtaining MRI and CBCT images of all TMJs of the subjects, evaluation and measurement were conducted, respectively. The analyzed parameters included disc position, disc configuration, joint effusion (JE), joint space or condyle position, and condylar bony changes. Of the 38 joints in the study group, disc deformity and disc displacement of TMJs were both 57.9% when the mouth was closed, and 76.3% showed condylar bony changes, while when the mouth was open, 82% of all TMJs showed physiological biconcave discs. Comparison of joint space revealed that the anterior space was larger in the study group. There was no significant difference between the mild and the moderate to severe sleep bruxism subgroups in the changes of TMJ. The results demonstrated that a higher prevalence of disc deformity, disc displacement, JE, and condylar bony changes occurred in temporomandibular joints of sleep bruxers. These changes were not related to the severity of sleep bruxism.

Automatic temporomandibular disc displacement diagnosis via deep learning

Temporomandibular joint (TMJ) disc displacement is a common condition that required magnetic resonance imaging (MRI) for diagnosis. However, it has occasionally been challenging for doctors to make a firm diagnosis based on TMJ MRI due to imaging concerns and the significant requirement for clinical competence. As a result, a Multimodal Stepped Attention Net (MSANet) was built in this study, and a deep learning network was used to train the assisted diagnosis AI model (TMJ MRI-Net).A total of 600 patients were recruited, including 1200 lateral joint MRI sequences, which are made up of eight consecutive images for each lateral joint. 11 sides of cases with poor image quality were excluded. MSANet combining multimodal technology and attention mechanism was proposed and designed for this study, which mainly included Area Detection Module and Feature Network.The whole experiment was designed according to stard standard. There is statistically significant difference between the least square mean of diagnosis time for the physicians (from TMJ, Orthodontics and General Dentistry) with AI (TMJ MRI-Net) assistance group (16.15, 95% CI:10.88–21.41) and the physician only group (21.01, 95%CI: 15.74–26.28). The AUC, sensitivity and specificity of patients whether is disc displacement and patients whether the disc displacement is with/without reduction for the physicians' diagnoses were all statistically improved by the assistance of AI. In addition, AUC and specificity were improved for three different specialties with the AI assistance. Meanwhile, AI can help to save reading time for physicians from all three departments, and the increment was statistically significant.To conclude, the AI-assisted strategy significantly improved the diagnostic accuracy of physicians (especially in General Dentistry) on anterior disc displacement in TMJ MRI and improve diagnostic efficiency.