Disc Displacement Research Articles

Relationship Between Occlusal Factors and Temporomandibular Disorders: A Systematic Literature Review.

Temporomandibular disorders (TMD) originate from various components within the temporomandibular joint (TMJ), causing an impact on the masticatory muscles, the joint itself, and associated structures. They are a widely prevalent issue across the world. According to epidemiological research, up to 50% of adults in the population have TMD-related symptoms. The objective of this work was to analyze the existing scientific literature regarding the association between malocclusion classes, bruxism, and tooth loss in relation to the etiology of TMD. This systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 analysis protocol. For the development of the question focus, the population, intervention, control, and outcomes (PICO) study design protocol was used. The question in focus according to the PICO format was: "Do malocclusion, tooth loss, and bruxism contribute to temporomandibular disorders?". The review was performed with articles from PubMed, Web of Science, and Google Scholar databases according to the specified inclusion and exclusion criteria. The included articles were not older than five years. The risk of bias was assessed in the included studies by using the Cochrane Risk-of-bias 2 (RoB-2) tool. Out of a total of 32 results received, 21 articles were chosen according to the established criteria after conducting a review and analysis of their full texts. The article search sequence was presented in the PRISMA 2020 flow diagram, and the outcomes of the chosen articles were presented. The literature results revealed a relationship between occlusion and the development of TMD. The influence of occlusal factors on the TMJ was explained by an examination of joint anatomy and symptoms related to TMD. This study revealed variations in TMJ factors across different malocclusion classes. Additionally, it was observed that the occurrence and attributes of TMD are influenced by the number of tooth loss quadrants and the frequency of missing teeth. Furthermore, a correlation was found between bruxism and the symptoms of TMD, including myofascial pain, disc displacement, arthralgia, and muscle disorders. This literature review provides comprehensive information on the relationship between malocclusion classes, bruxism, tooth loss, and TMDs. This prompts healthcare professionals to prioritize patients' occlusal assessment and TMJ condition.

Cervical Disc Displacement in Military Pilots.

Cervical disc displacement (CDD) may disqualify pilots from flying and have a profound impact on military unit capability. The objective of this retrospective database review is to characterize the incidence and demographic predictors of symptomatic cervical spine disc displacement in pilots of fixed- and rotary-wing aircraft and ground-based controls. The Defense Military Epidemiology Database was queried for first-occurrence ICD-9 code 722.0: CDD cases from 2007 to 2015. Injury count rates among aircraft groups and overall incidence per 1,000 person-years were calculated and standardized for age, gender, and military rank, and 95% confidence intervals (CIs) were compared to determine significance. There were 934 new cases of CDD among active duty U.S. Military pilots during the study period. The overall incidence of CDD in all pilots during this time frame was 2.715 per 1,000 person-years (95% CI, 2.603-2.830). Helicopter pilots had a significantly higher incidence compared to all other aircraft pilots and crew at 3.79 per 1,000 person-years (95% CI, 3.48-4.13). This finding remained statistically significant after standardizing for age, gender, and rank. Among all military officers, increasing age was a risk factor for CDD. The U.S. Military helicopter pilots have an increased risk compared to fixed-wing pilots and non-pilot controls. CDD remains a rare, though career-threatening, condition. Increased education and awareness training are warranted for both helicopter pilots and flight physicians to recognize signs and symptoms of cervical pathology. Continued investigations into preventive measures to minimize injury and time unfit for flight are warranted.

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.

Effectiveness of Rehabilitation for Disk Displacement of the Temporomandibular Joint—A Cross-Sectional Study

(1) Background: Dislocations of articular disk can occur as a result of parafunctions in the Temporo Mandibular Joint (TMJ), which limits the opening of the mandible and other movements. The aim of this study was to evaluate the effectiveness of rehabilitation in patients with disk displacement of the TMJ. A total of 327 subjects with Temporo Mandibular Disorders underwent stomathognatic physiotherapy. (2) Methods: Based on the results obtained by a manual functional analysis, 35 patients who were identified with articular disk locking (disk displacement without reduction) were included in the study. The study group (N = 35) was subjected to passive repositioning of the articular disk, reposition splints, and physiotherapy. The patient’s TMJs were then examined before the therapy, immediately after the therapy, and during the follow-up visit 3–6 weeks after the therapy. The Diagnostic Criteria for the Most Common Intra-articular Temporomandibular Disorders was used to evaluate the effects of rehabilitation on the patients’ range of motions and the Numeric Pain Rating Scale (NPRS). For the statistical analysis, Pearson’s r correlation coefficient test and Wilcoxon signed-rank test were used. (3) Results: The results showed a significant improvement in the range of motion of the mandible movements. The level of improvement was dependent on the time from the incident until undergoing rehabilitation. (4) Conclusions: The stomatognathic physiotherapy applied increased the range of motion of the mandible and reduced pain levels to the expected range.

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

ObjectiveTo investigate the relationship between upper airway dimension and craniocervical posture in adult patients with bilateral anterior disc displacement and to provide some references for clinical diagnosis and plan formulation in orthodontics. MethodsBased on RDC/TMD (Research Diagnostic Criteria for Temporomandibular Disorder), 98 Patients were divided into three groups by two experienced TMJ (Temporomandibular Joint) specialists: bilateral disc normal position group (BN), bilateral anterior disc displacement with reduction group (ADDWR) and bilateral anterior disc displacement without reduction group (ADDWoR). Inter-group comparison and correlation analysis were performed after 11 craniocervical posture and 15 upper airway dimension measurements finished with Dolphin and Uceph software in Two or Three-dimensional. ResultsAnterior disc displacement often accompanied with extension of craniocervical posture, as ADDWR and ADDWoR groups have significantly higher cervical curvature and inclination than BN group (P < 0.05). Simultaneously anterior disc displacement often associated with constrained upper airway dimension for the total and each segment upper airway volume were significantly smaller in ADDWR and ADDWoR than BN group (P < 0.05). Correlation analysis revealed that C0-C1 (the distance from the base of the occipital bone (C0) to the posterior arch of the atlas (C1)) is significantly related to the total and each segment upper airway volume reduction (P < 0.05). ConclusionThere exists markedly close correlation between anterior disc displacement and craniocervical posture forward extension, which may be physiologically adaptive cervical extension to keep oropharyngeal airway unobstructed as upper airway dimension constrained by anterior disc displacement. Clinical relevanceThese findings allow us to infer the potential consequences if the treatment of anterior disc displacement would result in an improvement of intervertebral relationships and upper airway constraint.

Investigation of incidental findings of temporomandibular joint disorders on brain magnetic resonance imaging in three-dimensional T2-weighted SPACE sequence performed for brain imaging.

The study aimed to determine the temporomandibular joint (TMJ) findings, to investigate the prevalence contribution of this sequence on cases in which cranial magnetic resonance examination was performed and three-dimensional (3D) T2-SPACE (T2-weighted sampling perfection with application-optimized contrasts using different flip-angle evolutions) sequence was used by retrospectively scanning the magnetic resonance imaging (MRI) archive of our hospital, and to reveal the advantages of the 3D-T2 SPACE sequence in patients with TMJ disorders. The cross-sectional retrospective study was conducted with 499 patients (289 females, 210 males; mean age: 50.1±17.7 years; range, 8 to 92 years) who underwent brain MRI and had 3D-T2 SPACE between March 1, 2021 and March 1, 2022. Two radiologists analyzed the TMJs of the subjects included in the study in 3D-T2 SPACE sequences. At least one incidental finding was detected in the TMJ in 37.1% (n=185) of the patients included in our study. In our study, the most common (13.6%) MRI findings were osteoarthritic changes and synovial cysts. Joint effusion (13.2%) and disc displacement (9%) were less frequent. When the relationship between the age of the patients and the presence of incidental findings, degeneration, effusion, disc displacement, and cyst was examined, the age of the patients with incidental findings (p=0.001) and osteoarthritic changes (p<0.001) was statistically significantly higher. Incidental findings, particularly osteoarthritic changes and synovial cysts, can be seen quite commonly in the TMJ in brain MRI using 3D T2-SPACE sequences in the general population. The 3D T2-SPACE sequence provides valuable information in the recognition of TMJ disorders.

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

ObjectiveTo study the changes of temporomandibular joints and craniocervical posture in adult patients with bilateral anterior disc displacement, and to explore their correlation, which may provide some clinical value for clinical diagnosis and treatment planning.MethodsNinety-eight adult patients were divided into 3 groups: 29 patients in bilateral disc normal position group (BN), 33 patients in bilateral Anterior Disc Displacement With Reduction group (ADDWR) and 36 patients in bilateral Anterior Disc Displacement Without Reduction group (ADDWoR). Dolphin and Uceph software were used to measure 14 items of temporomandibular joint and 11 items of craniocervical posture for comparison and correlation analysis between groups.ResultsThere were significant differences in bilateral joint space between three groups. Compared with the BN, the anteroposterior diameter of the condyle was significantly reduced, the condyle was significantly displaced posteriorly and superiorly in the ADDWR and ADDWoR, but the joint fossa width and joint fossa depth did not change significantly. Cervical curvature and inclination were greater in patients with anterior disc displacement than BN, indicating that the craniocervical posture of adult patients with anterior disc displacement was extended and protrusive.ConclusionAnterior disc displacement of the temporomandibular joint can displace the condyle upwards and posteriorly and reduce the anteroposterior diameter of condyle, and then make the condyle closer to the wall of articular fossa to induce joint symptoms. Additionally, craniocervical postural position is significantly affected, which may be related to compensate for the effects of airway space.

Analysis of clinical changes and magnetic resonance imaging features of 37 patients with temporomandibular joint disc condylar complex with anterior disc displacement without reduction.

This study aims to investigate clinical outcomes, imaging changes, and age differences with regard to temporomandibular joint disc condylar complex with anterior disc displacement without reduction (ADDWoR). A total of 37 patients (45 lateral joints) with ADDWoR who were admitted to The First Affiliated Hospital of Zheng Zhou University from January 2016 to June 2023 were selected. The patients were composed of 4 males and 33 females and had an average age of 23.5 years. The average course of the disease was 14.4 months. Clinical and magnetic resonance imaging (MRI) data were collected at the end of initial diagnosis and follow-up, and the length and thickness of the articular disc, the angle of the disc condyle, and the height of the condyle were measured. The statistical significance of the changes was assessed using SPSS 25.0 software package. At the end of follow-up, disc displacement in three patients (three lateral joints) was healed. Approximately 48.4% of the patients felt that limitation of mandibular movement was not alleviated; 58.3% of patients reported that pain during mouth opening was not reduced; 54.5% reported pain while chewing; 33.3% of the patients showed facial deviation, and only one showed remission. The mean disk-condyle angle increased from 61.63° to 67.81°. The average length of articular disc shortened from 8.20 mm to 7.27 mm, and the height of the condyle significantly decreased from 23.17 mm to 22.76 mm (P<0.05). The absorption ratio of the condyle increased, and no significant differences in the changes of joint soft and hard tissues between the adolescent and adult groups (P>0.05). In different age groups of patients with ADDWoR, clinical symptoms cannot be completely relieved. The disc is anteriorly displaced and shortens, condylar height decreases, and secondary facial asymmetry and mandibular retraction occur.

Role of MRI in detection of lumber spine pathologies using 1.5 tesla (MRI)

Background: This study investigates the diagnostic accuracy of MRI in detecting various lumbar spine pathologies in patients with lower back pain. Lower back pain (LBP) is a prevalent issue affecting 80%–85% of the population during their lifetime, contributing significantly to global disability. LBP is nonspecific in 95% of cases but can stem from underlying pathologies such as disc herniation, spinal stenosis, infection, inflammation, tumours, or fractures. Objective: To emphasize the importance of magnetic resonance imaging (MRI) in patients suspected of lumbar spinal examinations. Methods and material: The research focused on adult patients with radicular syndrome, spinal stenosis, spinal tumours, spinal fractures, spinal infection/inflammation, disc herniation, spondylolisthesis, spondylolysis, ankylosing spondylitis, disc displacement, osteoporotic fractures, and other degenerative disc diseases. Utilizing a 1.5 Tesla MRI machine, the descriptive, cross-sectional observational study spanned one year and included 150 patients. Results: revealed that diffuse disc bulge (87.33%) and disc protrusion (87.33%) were the most common pathologies, followed by partial desiccation (34.67%), neural foramina stenosis (16.00%), spondylosis (1.33%), osteoporosis (12.00%), spinal haemorrhage (2.00%), osteophyte spurs (29.33%), and sclerotic changes (3.33%). Discussion and Conclusion: The study's discussion highlighted notable findings, including a higher prevalence of lumbar spine abnormalities in females (51.33%) and a substantial association with a history of lower back pain (40.00%). The conclusion underscores the significance of MRI in diagnosing lumbar spine pathologies, with specific attention to the prevalence of disc bulge and protrusion in the studied population.

Effect of Articular Cavity Injection Combined with Bite Splint Treatment on Anterior Disc Displacement Without Reduction

Objective: To observe the clinical effect of articular cavity injection combined with bite splint therapy for the treatment of anterior disc displacement without reduction (ADDWoR). Methods: The research subjects for this study were 30 patients with ADDWoR treated in the temporomandibular joint specialist outpatient clinic from November 2018 to November 2019, with a disease duration of 1 to 6 months. The treatment group was treated with an articular cavity injection of sodium hyaluronate + bite splint. The control group was treated with a simple articular cavity injection of sodium hyaluronate. The two groups were followed up once every 2 weeks to evaluate the treatment effect and observe the clinical efficacy of the two groups. Statistical analysis was carried out using SPSS 24.0. t-test and general linear regression analysis were carried out to compare the data of both groups, and χ2-test and binary logistic regression analysis were performed for pain index comparison. Results: There was no significant difference in terms of the efficacy of the treatment received by both groups. The mouth opening and joint pain of patients in both groups were significantly improved after treatment (P &lt; 0.001). Conclusion: Articular cavity injection of sodium hyaluronate and occlusal splint therapy are both effective and safe methods for treating ADDWoR.

EVALUATION OF THE CONDYLAR POSITION IN RELATION TO THE DIFFERENT MALOCCLUSIONS OF A STUDENT POPULATION

Studying the position of the condyle in the glenoid cavity is an important aspect of achieving the diagnosis and the treatment plan in dentistry. The posterior position of the condyle in the glenoid cavity is not a completely reliable predictor of the lack or appearance of disc displacement, although they are related (1). The TMJ is a small joint with a complex morphology surrounded by bony tissues that create a superimposition of images, especially in the petrous region of the temporal bone, the mastoid process and the articular eminence (1). Studies on the ideal position of the condyles have shown that the healthiest condyle-fossa relationship in which the condyle is centered anteriorly in the mandibular fossa. The following research aims to evaluate the condylar position in relation to different malocclusions of thirty-two students of the Faculty of Dentistry of the University of Cuenca.The research has a quantitative approach, carried out by means of numerical analysis. The population used was thirty-two students from the Faculty of Odontology in the University of Cuenca, aged between 21 and 29 years, who underwent cone beam computed tomography. The research was carried out as a descriptive retrospective sample and provides systematic information. The research used is of a primary source, using CBCT scans obtained from an image bank at the CERIOM Radiology Centre in the city of Cuenca, and the tomographic examination will be imported in DICOM format into the RadiAnt DICOM Viewer software (64-bit).

Analysis of unsteady MHD fluid flow across two parallel discs with uniform fluctuation subject to modified Hall and activation energy

This study intends to examine the consequences of the externally applied magnetic field and modified Hall effect on nanofluid flow across two symmetrically spinning and extending discs, where continuously the upper disc moves upward and downward. The lower disc is vertically fixed. The discs rotate and move vertically, generating a 3D flow. The mass density, heat transfer and flow motion have been evaluated and modeled in the form of the system of partial differential equations (PDEs) with an additional influence of activation energy, heat source and chemical reaction. The system of PDEs is modified to an ordinary set of differential equations by employing the resemblance substitution method. The obtained system of ODEs is further solved through the numerical approach (bvp4c). The results are compared to the bvp4c package and published work for validity purposes. In the case of downward displacement of the upper disc, magnetic and Hall characteristics have a significant impact on the velocity curve. The energy curve elevates with the upward movement of the disc, while it reduces with the downward fluctuation. Furthermore, the mass transmission rate enhances with the influence of hall current, while diminishing with the impact of chemical reaction rate.

Analysis of joint protein expression profile in anterior disc displacement of TMJ with or without OA.

Anterior disc displacement (ADD) is a common clinical issue and may cause osteoarthritis (OA). However, the research of protein changes in synovial fluid as disease development marker and potential treatment clue is still insufficient. We conducted the high-resolution mass spectrometry (MS) of synovial fluid collected from 60 patients with normal disk position to ADD and ADD with osteoarthritis (OA). The proteins with significant changes among the 3 groups were analyzed by biological information and further validated by in primary rat condyle chondrocytes and OA animal model. FGL2, THBS4, TNC, FN1, OMD etc. were significantly increased in ADD without OA (p < 0.05), which reflected the active extracellular matrix and collagen metabolism. FGFR1, FBLN2, GRB2 etc. were significantly increased in ADD with OA group (p < 0.05), which revealed an association with apoptosis and ferroptosis. Proteins such as P4HB, CBLN4, FHL1, VIM continuously increase in the whole disease progress (p < 0.05). Both the invitro and invivo results are consistent with protein changes detected in MS profile. This study firstly provides the expression changes of proteins from normal disc condyle relationship toward ADD with OA, which can be selected and studied further as disease progress marker and potential treatment targets.

Comparison of disc position stability and condylar bone remodelling between two open disc repositioning surgeries: a retrospective single-centre cohort study.

Open suturing (OSu) and mini-screw anchor (MsA) are two commonly used open disc repositioning surgeries for anterior disc displacement (ADD) of the temporomandibular joint (TMJ). This study assesses the differences in disc position stability (DPS) and condylar bone remodelling (CBR) between these two surgical procedures in a single centre. A retrospective cohort study using MRI scans (pre-operation, 1 week and 12months post-operation) of all patients who had open TMJ disc repositioning surgery from January 2016 to June 2021 at one centre through two surgical techniques (OSu and MsA) was performed. The predictor variable was technique (OSu and MsA). Outcome variables were DPS and CBR. During follow-up, DPS was rated as good, acceptable and poor, and CBR was graded as improved, unchanged, and degenerated. Multivariate analysis was used to compare the DPS and CBR at 12 months after adjusting five factors including age, sex, Wilkes stage, preoperative bone status (normal, mild/moderate abnormal) and the degree of disc repositioning (normal, overcorrected, and posteriorly repositioned). Relative risk (RR) for DPS and CBR was calculated by multivariate logistic regression. Three hundred eighty-five patients with 583 joints were included in the study. MRIs at 12 months showed that 514 joints (93.5%) had good DPS, and 344 joints (62.5%) had improved CBR. Multivariate analysis revealed that OSu had higher DPS (RR=2.95; 95% CI, 1.27-6.85) and better CBR (RR=1.58; 95% CI, 1.02-2.46) than MsA. Among the factors affecting DPS, females had better results than males (RR=2.63; 95% CI, 1.11-6.26) and overcorrected or posteriorly repositioned discs were more stable than normally repositioned discs (RR=5.84; 95% CI, 2.58-13.20). The improvement in CBR decreased with age increasing (RR=0.91; 95% CI, 0.89-0.93). Preoperative mild/moderate abnormal bone status had a higher probability of improved CBR compared to normal preoperative bone status (RR=2.60; 95% CI, 1.76-3.83). OSu had better DPS and CBR than MsA. Sex and the degree of disc repositioning impacted DPS, while age and preoperative bone status affected CBR.

Posterior Percutaneous Endoscopic Cervical Discectomy for Single-Level Soft, Huge Central Disc Herniation

BACKGROUND: Posterior percutaneous endoscopic cervical discectomy (PPECD) has been proven safe and effective for foraminal cervical disc herniation (CDH). However, central CDH has long been considered as the contraindication of PPECD, because the path is obstructed by the spinal cord and nerve root. OBJECTIVES: To preliminarily assess the feasibility, safety, and effectiveness of PPECD for single-level soft, huge central CDH. STUDY DESIGN: A retrospective cohort study. SETTING: Zhejiang Provincial People’s Hospital (Affiliated People’s Hospital, Hangzhou Medical College). METHODS: Between 2017 and 2020, 31 patients diagnosed with single-level soft, huge central CDH were treated by PPECD. Primary outcomes included the measures of neck and radicular pain based on the numeric rating scale (NRS) and cervical neurologic status based on the Japanese Orthopedic Association (JOA) score. The global outcome was assessed using the Odom’s criteria at one-year follow-up. RESULTS: Compared to the baseline, there was a constant and significant reduction of NRS-rated pain and improvement of JOA-rated cervical neurologic status postoperatively (P &lt; 0.01). According to the Odom’s criteria, 96.8% (30/31) of patients had satisfactory postoperative clinical improvement (excellent or good outcomes) at one-year follow-up. Complications included C5 nerve root palsy and spinal cord injury. The total complication rate was 16.5% (2/31), but these complications were temporary and not catastrophic. LIMITATIONS: The limitations of this study include the volume of the sample, a short follow-up period, and the lack of a control group. CONCLUSIONS: Our preliminary experience indicates that PPECD is a feasible and promising alternative for symptomatic single-level soft, huge central CDH. KEY WORDS: Intervertebral disc displacement, minimally invasive surgical procedures, diskectomy, endoscopy

Evaluation of masticatory muscles in temporomandibular joint disorder patients using quantitative MRI fat fraction analysis-Could it be a biomarker?

Temporomandibular joint disorders (TMDs) are closely related to the masticatory muscles, but objective and quantitative methods to evaluate muscle are lacking. IDEAL-IQ, a type of chemical shift-encoded magnetic resonance imaging (CSE-MRI), can quantify the fat fraction (FF). The purpose of this study was to develop an MR IDEAL-IQ-based method for quantitative muscle diagnosis in TMD patients. A total of 65 patients who underwent 3 T MRI scans, including CSE-MRI sequences, were retrospectively included. MRI diagnoses and clinical data were reviewed. There were 19 patients in the normal group and 46 patients in the TMD group with unilateral disc displacement. The TMD group was subdivided into those with and without clenching. The right and left FF values of the masseter, medial, and lateral pterygoid muscles were measured twice by two oral radiologists on CSE-MRI, and the average value was used. FF measurements using CSE-MRI showed excellent intra- and inter-observer agreement (ICC > 0.889 for both). There were no statistically significant differences between the right and left FF values in the masseter, medial pterygoid, and lateral pterygoid of the normal group (p > 0.05). A statistically significant difference was found in the TMD group without clenching, in which the masseter muscle had a statistically significantly lower FF value on the disc displacement side (3.94 ± 1.61) than on the normal side (4.52 ± 2.24) (p < 0.05). CSE-MRI, which can reproducibly quantify muscle FF values, is expected to be a biomarker for objective muscle evaluation in TMD patients. The masseter muscle is expected to be particularly useful compared to other masticatory muscles, but further research is needed.

Comparison of T2 values of the displaced unilateral disc and retrodiscal tissue of temporomandibular joints and their implications

Unilateral anterior disc displacement (uADD) has been shown to affect the contralateral joints qualitatively. This study aims to assess the quantitative T2 values of the articular disc and retrodiscal tissue of patients with uADD at 1.5 Tesla (T). The study included 65 uADD patients and 17 volunteers. The regions of interest on T2 maps were evaluated. The affected joints demonstrated significantly higher articular disc T2 values (31.5 ± 3.8 ms) than those of the unaffected joints (28.9 ± 4.5 ms) (P < 0.001). For retrodiscal tissue, T2 values of the unaffected (37.8 ± 5.8 ms) and affected joints (41.6 ± 7.1 ms) were significantly longer than those of normal volunteers (34.4 ± 3.2 ms) (P < 0.001). Furthermore, uADD without reduction (WOR) joints (43.3 ± 6.8 ms) showed statistically higher T2 values than the unaffected joints of both uADD with reduction (WR) (33.9 ± 3.8 ms) and uADDWOR (38.9 ± 5.8 ms), and the affected joints of uADDWR (35.8 ± 4.4 ms). The mean T2 value of the unaffected joints of uADDWOR was significantly longer than that of healthy volunteers (P < 0.001). These results provided quantitative evidence for the influence of the affected joints on the contralateral joints.

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.

The Contemporary Management of Temporomandibular Joint Intra-Articular Pain and Dysfunction

The understanding of the causes of temporomandibular joint pain and dysfunction has evolved over 50years. Historically, the term internal derangement has been used to describe the abnormal relationship between the articular disc, condyle, and glenoid fossa, which was thought to correlate with patient symptoms. It is now known that the pathophysiology of intra-articular pain and dysfunction (IPD) involves synovitis, capsular impingement, symptomatic disc displacement, or a combination of these. Symptomatic disc displacement should only be considered to be a potential source of IPD after synovitis and capsular impingement have been treated. This philosophy provides the opportunity for most patients with IPD to be initially treated nonsurgically or with minimally invasive procedures such as arthrocentesis or arthroscopy.

Detecting anteriorly displaced temporomandibular joint discs using super-resolution magnetic resonance imaging: a multi-center study.

Background: Magnetic resonance imaging (MRI) plays a crucial role in diagnosing anterior disc displacement (ADD) of the temporomandibular joint (TMJ). The primary objective of this study is to enhance diagnostic accuracy in two common disease subtypes of ADD of the TMJ on MRI, namely, ADD with reduction (ADDWR) and ADD without reduction (ADDWoR). To achieve this, we propose the development of transfer learning (TL) based on Convolutional Neural Network (CNN) models, which will aid in accurately identifying and distinguishing these subtypes. Methods: A total of 668 TMJ MRI scans were obtained from two medical centers. High-resolution (HR) MRI images were subjected to enhancement through a deep TL, generating super-resolution (SR) images. Naive Bayes (NB) and Logistic Regression (LR) models were applied, and performance was evaluated using receiver operating characteristic (ROC) curves. The model's outcomes in the test cohort were compared with diagnoses made by two clinicians. Results: The NB model utilizing SR reconstruction with 400 × 400 pixel images demonstrated superior performance in the validation cohort, exhibiting an area under the ROC curve (AUC) of 0.834 (95% CI: 0.763-0.904) and an accuracy rate of 0.768. Both LR and NB models, with 200 × 200 and 400 × 400 pixel images after SR reconstruction, outperformed the clinicians' diagnoses. Conclusion: The ResNet152 model's commendable AUC in detecting ADD highlights its potential application for pre-treatment assessment and improved diagnostic accuracy in clinical settings.