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.

The Role of the Lateral Pterygoid Muscle in Articular Disc Displacement: A Cross-Sectional Magnetic Resonance Imaging Study

Background: Determination of the role of the Lateral Pterygoid Muscle LPM in the articular disc displacement ADD is controversial referring to the variations in the pattern of insertion of the Superior Lateral Pterygoid Muscle SPLM. Introduction: it was well understood that the superior head of the lateral pterygoid muscle has only a single insertion pattern among individuals in which the muscle is attached to the articular disc and capsule. However, recent findings in many studies have shown a noticeable variation in the insertion pattern of the upper LPM. Method: MRI examinations were collected at King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia. Scans of 61 patients (41 females, 20 males, mean age 33 years old) with symptoms of temporomandibular dysfunction were reviewed retrospectively. The direction of their articular disc displacement was evaluated through sagittal and coronal views in both open and closed mouth positions. Results: There was no statistical significance found between the LPM attachment types and TMJ disc position. The chi-square test also showed no significant difference between the type of LPM attachment and the condylar location. Forty-five percent of the articular discs were located between the articular eminence and the glenoid fossa. The majority of the disc displacement was in the anterior direction. Conclusion: There was no statistically significant association between the type of LPM attachments and the direction of disc displacement.

Motion Analysis of Triangular Fibrocartilage Complex by Using Ultrasonography Images: Preliminary Analysis

The triangular fibrocartilage complex (TFCC) is a significant stabilizer of the distal radioulnar joint. Diagnosing TFCC injury is currently difficult, but ultrasonography (US) has emerged as a low-cost, minimally invasive diagnostic tool. We aimed to quantitatively analyze TFCC by performing motion analysis by using US. Twelve healthy volunteers, comprising 24 wrists (control group), and 15 patients with TFCC Palmer type 1B injuries (injury group) participated. The US transducer was positioned between the ulnar styloid process and triquetrum and was tilted ulnarly 30° from the vertical line. The wrist was then actively moved from 10° of radial deviation to 20° of ulnar deviation in a 60-rounds-per-minute rhythm that was paced by a metronome. The articular disc displacement velocity magnitude was analyzed by using particle image velocimetry fluid measurement software. The mean area of the articular discs was larger on ulnar deviation in the control group. The mean articular disc area on radial deviation was larger in the injury group. The average articular disc velocity magnitude for the injury group was significantly higher than that for the control group. The results suggest that patients with TFCC injury lose articular disc cushioning and static stability, and subsequent abnormal motion can be analyzed by using US.

Results of Using Arthrocentesis in the Treatment of Temporomandibular Disorders Associated with Fractures of the Mandibular Condylar Process

The purpose of the work was to study the effectiveness of arthrocentesis in the complex treatment of post-traumatic temporomandibular disorders. Materials and methods. The clinical part of the study included 24 patients, who had a history of fractures of the mandibular articular process. Patients underwent radiological examination – orthopantomography, computer tomography, ultrasound and magnetic resonance. Patients with titanium mini-plates after osteosynthesis were subjected to ultrasound, and since the reposition and fixation of fragments was performed using intermaxillary fixation they were subjected to magnetic resonance imaging. Pain assessment was performed according to visual analogue scale. Temporomandibular joint arthrocentesis was performed according to a modified method of D. Nitzan (1991) under local anesthesia. Results and discussion. All patients complained of the temporomandibular joint pain, which was rated from 1 to 6 points. All patients noted pain on palpation of the temporomandibular joint. Limited mouth opening ranging from 30 to 38 mm was found in 11 patients. Lower jaw deviation was observed in 18 patients. All patients had articulatory noises – clicking, and 11 had blocked movement of the joint head. Orthopantomograms or computer tomography revealed satisfactory restoration of the anatomical shape of the mandible after fractures and complete consolidation of the fracture. Ultrasound and magnetic resonance revealed signs of unabsorbed hematoma as consequences of hemarthrosis; in 18 patients – deformity of the capsule, in 17 – a slight thickening of the posterior edge of the articular disc, in 18 patients – disc adhesion, in 13 people – forward disc displacement with reduction, in 11 patients – disc protrusion without reduction. According to clinical and radiological signs after traumatic temporomandibular disorders, patients were divided into two groups according to Wilkes classification: 13 patients with stage II (early-middle) and 11 – with stage III (middle). We also found that after surgical treatment – osteosynthesis, the number of patients with stage III according to Wilkes makes up 58.33% (7 people), while those after splinting – 33.33% (4 people). The control ultrasound and MRI carried out 3-6 months after arthrocentesis showed no signs of hemarthrosis in 11 (84.61%) patients with intra-articular disorders of the second degree, and in 8 (72.72%) patients with internal disorders of the third degree, the position and function of the articular disc were restored. Conclusion. Arthrocentesis with temporomandibular joint lavage is a minimally invasive surgical manipulation that has proven itself in temporomandibular disorders of traumatic origin, in particular after fractures of the articular process of the mandible. Arthrocentesis is recommended to be used after ineffective conservative treatment, as well as to prevent post-traumatic intra-articular disorders in the early post-treatment fractures (intermaxillary fixation or osteosynthesis) with the attenuation of acute post-traumatic events, which is our goal of further work

Análise microscópica na articulação temporomandibular a partir da mudança de direção do vetor de força da mandíbula em relação à base do crânio : estudo experimental em coelhos (Oryctolagus cuniculus l.)

The correlation between TMJ's growing, structure and function is consensual in the specialized literature. Until the moment, the little knowledge about post-birth changes are studied by observation of condylar growth and disc reestructuration. In an experimental model in rabbits (Oryctolagus cuniculus 1.), it was observed tecidual alterations of the TMJ's components — mandibular condyle, articular disc and temporal bone, face to a direction change of mandibular power axis, which has the incidence upon these structures. Twentyfour rabbit were divided in four groups. Two of each group formed a control group. Four experimental periods were established 15, 30, 60 and 90 days. The animals from the experimental group were submitted to surgical procedure involving the mandible right side, changing the direction of mandibular power axis, which has incidence in the TMJ. Histological observations of TMJ in the control group, at different times, the growth and development of this structure were showed, compatible to the normality. At experimental group, the change of mandibular power axis caused alteration of the mandibular condyle and the discal structure. Significative responses at temporal bone were observed too, as a process of osseous modelation, suggestive of growth of this cranial structure.

MRI-based observation of the size and morphology of temporomandibular joint articular disc and condyle in young asymptomatic adults

Objective: To investigate the size and morphology of the temporomandibular joint (TMJ) articular disc and condyle in young asymptomatic adults by using magnetic resonance imaging (MRI) and to provide a reference for clinical diagnosis and scientific study of temporomandibular disorders (TMD). Methods: Overall, 93 undergraduate volunteers without TMD were enrolled from the freshmen pool at the Qingdao University. All participants underwent MRI of the oblique sagittal and oblique coronal TMJ planes. The articular disc and condyle were subsequently measured, and their morphology was evaluated. The obtained data were then grouped and analyzed statistically. Finally, intragroup correlation coefficient (ICC) was used to evaluate the interobserver measurement reliability. Results: We totally received 186 TMJ imaging samples. Based on our analysis, disc’s anterior band in young asymptomatic adult females were thicker than males of the same age (p = 0.024). Moreover, the media-lateral dimensions of the condylar head of adult females were shorter than males of equal age (P＜0.001). The bilateral articular disc morphology was the same in 72.4% of subjects while the condylar morphology was the same in 63.4% of participants. Finally, using measurement reliability assessment, we demonstrated that our conclusions are reliable (ICC ≥0.7). Conclusion: The thickness of the anterior band of the disc and the media-lateral dimensions of the condylar head were gender-related. Additionally, the morphology of the bilateral articular disc and condyle was different among the subset of young asymptomatic adults.

Disorders of the statics of the body and the temporomandibular joint

INTRODUCTION The temporomandibular joint is a synovial, complex (hinge-sliding) joint that connects the temporal bone with the mandible by means of an articular disc. Temporomandibular joint dysfunctions most often concern several disease entities and include various symptoms and ailments. One of the first symptoms of the disease is pain that stems from a muscle or joint. In addition, we can observe: limitations in the mobility and range of movement of the jaw, problems with chewing food, crackles in the joint, pain in pressure and touch of the muscles, earaches and noise or changes in the appearance of the face (the so-called "square face"). Any deviation from the correct body posture is called a posture defect. OBJECTIVE The main aim of the study is to present the significant relationship between disturbed statics of the body and the temporomandibular joint, thanks to which we can explain the importance of proper planning of diagnostics as well as conducting dental and physiotherapeutic therapy. THE WEIGHT OF THE BODCIES The materials used to write the article include scientific works from 1992-2021. The data was collected using the PubMed search engine and manual filtering. 80 publications were qualified for the analysis. SUMMARY According to the analyzed literature, we believe that there is a relationship between disturbances in the body statics and the stomatognathic system. The complexity of the issue shows that it is important to conduct multi-directional and interdisciplinary therapy.

Characterization of the articular disc and mandibular condyle in healthy individuals and individuals with temporomandibular disorders in relation with several symptoms—ultrasound study

Background Evaluate dimension of the articular disc and condyle between volunteers and patients with temporomandibular joint (TMJ) disorders previously diagnosed. Understand the symptoms that TMJ can promote using the ultrasound modality. Approved ethics committees of IPC. Methods Sample n = 36, ages [18–45], control group (CG) (n = 20), pathologic group (PG)(n = 16). Images were acquired with US with a linear B-scan (10 MHz) in a transverse plane. Bilateral TMJ study was done with open and closed mouth. A validated questionnaire was done. Results Dimension of the right disc was 0.072 ± 0.021 cm to PG and 0.090 ± 0.018 cm to CG with open mouth. Close mouth was 0.082 ± 0.024 cm to the PG and 0.100 ± 0.014 cm to the CG.The results to the condyle were 0.0351 ± 0.044 cm to PG and 0.378 ± 0.043 cm to CG. To the left side the alterations were in the dimension of the articular disc, the PG with open mouth, 079 ± 0.024 cm and close mouth 0.081 ± 0.019 cm. Significant differences in the symptoms between groups were observed. Symptoms revel that 62.5% have headache and 87% present noise/crackle in the masticatory. Conclusions Right side the PG had reduced articular disc and condyle dimensions when compared to the healthy group. This study shows the possible differences in the articular disc and condyle in PG and CG, also permitted study the TMJ disorders in real time with accuracy. The questionnaire it was possible to determine the main symptoms of the TMJ disorders. These disorders are in relation with de alterations dimension of the articular disc.

Radiation Diagnostics in Treatment of Displacement of a Joint Disk of a Temp-Jaw Joint and Myofascial Disorders

Purpose: Determination of the volume and sequence of radiation studies in the treatment of patients with displacement of the articular disc of the temporomandibular joint (TMJ)and myofascial pain disorders. Material and methods: The study included 48 patients with displacement of the articular disc of the TMJ and myofascial pain disorders. Clinical criteria for articular displacement were confirmed by MRI and CBCT. Studies of the function of the masticatory muscles were carried out at the Synapsis electromyograph. All patients underwent complex treatment, including relaxation of the masticatory muscles and relief of pain using injections of botulinum toxin in the actual masticatory, temporal and lateral pterygoid muscles (LPM), followed by repositioning split therapy. For the introduction of muscle relaxant in LPM, we have developed and applied external periarticular injection access to LPM. The method is based on reaching the zone of joint attachment of the upper and lower heads of the LPM with MRI navigation. Surveillance continued for up to 12 months with MRI monitoring of the position of the articular disc. Results: The stages of treatment of SJS of the TMJ with control use of MRI and CT, as well as a method for the administration of botulinum toxin under MRI navigation, have been developed. The first stage included CT and MRI of the temporomandibular joint, the second stage – injections of botulinum toxin into the masticatory muscles using the developed periarticular access to the LPM with MRI navigation, as well as CBCT with a splint to control the new (established) position of the lower jaw; the third and fourth stages included continuation of the reduction splint therapy, correction of the splint, observation for 3-6 months with control CBCT after 6 months to assess the position of the mandible without splint. Achieved an increase in the posterior and upper temporomandibular joint distances and the correct position of the lower jaw. Conclusion: Performing radiation studies on time at certain stages of treatment, differing in their content and volume, provided a complete diagnosis, planning treatment measures and monitoring the results.