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.

The Accuracy of High Resolution Ultrasound in the Diagnosis of TMJ Disc Displacement in Comparison With MRI

Background The temporomandibular joint disorders (TMD) have been a major source of pathology. Being only second to chronic low back pain as a cause of pain and disability. MRI is currently considered the gold standard method for imaging of the TMJ. USG is a non-invasive, inexpensive procedure. And can provide a potential sensitive tool for diagnosis of anterior disc displacement. Aim of the work The aim of this study is to compare between the accuracy of ultrasound and MRI in diagnosis of TMJ disc displacement. Patients and Methods This study was carried out at the Radiology Department, Ain Shams University Hospitals. Twenty one patients with clinically suspected TMJ disc displacement underwent ultrasound (US) and MRI examination. Results The overall sensitivity of the US to diagnose disc displacement compared to MRI reached (94.7%), specificity (91.3%), Positive Predictive value (90.0%), Negative Predictive Value (95%) and accuracy (92.9%). The results indicated 1.8 mm was the most accurate cut-off distance between the articular capsule and the anterior surface of the mandibular condyle for diagnosis of MR positive disc displacement.

Using Autoplasma in Treatment of Secondary Arthrosis, Developed from Dislocation of TMJ Disc

22 patients diseased with secondary arthrosis, developed from dislocation of TMJ disc, were observed by the authors of the article. Between these patients were 17 females and 5 males. The age of patients was from 21 to 60 years. In the clinical case, the leading symptom was constant or periodical pain, located at the injured joint, limitation of mandibular movement, aggravation of pain while moving jaw and was attached with clicking in joint. In the complex treatment of this problematical disease, successfully and for the first time was used autoplasmolifting. Authors injected autoplasma once in 5-6 days, 6 injections on one course of treatment. After noted treatment, 18 patients all the symptoms were released, 4 patients condition got better there was slight pain left, while moving jaw. In 1 patient's case, the neuralgia of III branch of the trigeminal nerve was diagnosed and he received suitable treatment. In 3 cases there was necessary to include orthopedic/orthodontic treatment.

3D-Printed Polycaprolactone Reinforced Hydrogel as an Artificial TMJ Disc

The replacement of a damaged temporomandibular joint (TMJ) disc remains a long-standing challenge in clinical settings. No study has reported a material with comprehensively excellent properties similar to a natural TMJ disc. In this work, we designed a novel artificial TMJ disc using polyvinyl alcohol (PVA) hydrogel crosslinked by cyclic freeze-thaw and reinforced by 3D-printed polycaprolactone (PCL) implants. The mechanical properties and surface morphologies of the artificial TMJ disc and the natural goat TMJ disc were tested and compared via compression, tensile, cyclic compression/tensile, creep, friction, scanning electron microscopy, and atomic force microscopy. The fibroblasts and chondrocytes were cultured on the artificial TMJ disc for 1, 3, and 5 d for cytotoxicity testing. Importantly, the artificial discs were placed into the TMJs of goats in an innovative way to induce disc defect repair for 12 wk. The PVA + PCL artificial disc demonstrated mechanical strength similar to that of natural disc, as well as 1) better fatigue resistance, viscoelasticity, and hydrophilicity; 2) less creep; and 3) low friction, cytotoxicity, and cell adhesion. By repairing the defects of the TMJ disc in goats, the artificial disc demonstrated the ability to maintain joint stability and protect condylar cartilage and bone from damage. These promising results indicate the feasibility of using a PVA + PCL artificial TMJ disc in a clinical context.

Comparison of the Trueness of Fits of the Biphasic Transverse Isotropic and Kelvin Models to the Tensile Behavior of Temporomandibular Joint Disc

This technical brief explores the validity and trueness of fit for using the transverse isotropic biphasic and Kelvin models (first and second order generalized) for characterization of the viscoelastic tensile properties of the temporomandibular joint (TMJ) discs from pigs and goats at a strain rate of 10 mm/min. We performed incremental stress-relaxation tests from 0 to 12% strain, in 4% strain steps on pig TMJ disc samples. In addition, to compare the outcomes of these models between species, we also performed a single-step stress-relaxation test of 10% strain. The transverse isotropic biphasic model yielded reliable fits in reference to the least root mean squared error method only at low strain, while the Kelvin models yielded good fits at both low and high strain, with the second order generalized Kelvin model yielding the best fit. When comparing pig to goat TMJ disc in 10% strain stress-relaxation test, unlike the other two Kelvin models, the transverse isotropic model did not fit well for this larger step. In conclusion, the second order Kelvin model showed the best fits to the experimental data of both species. The transverse isotropic biphasic model did not fit well with the experimental data, although better at low strain, suggesting that the assumption of water flow only applies while uncrimping the collagen fibers. Thus, it is likely that the permeability from the biphasic model is not truly representative, and other biphasic models, such as the poroviscoelastic model, would likely yield more meaningful outputs and should be explored in future works.

Composite System of 3D-Printed Polymer and Acellular Matrix Hydrogel to Repair Temporomandibular Joint Disc

Tissue engineering is a promising approach to restore or replace a damaged temporomandibular joint (TMJ) disc. However, constructing a scaffold that can mimic biomechanical and biological properties of the natural TMJ disc remains a challenge. In this study, three-dimensional (3D) printing technology was used to fabricate polycaprolactone (PCL)/polyurethane (PU) scaffolds and PU scaffolds to imitate the region-specific biomechanical properties of the TMJ disc. The scaffolds were coated with polydopamine (PDA) and combined with a decellularized matrix (dECM). Then, rat costal chondrocytes and mouse L929 fibroblasts, respectively, were suspended on the composite scaffolds and the biological functions of the cells were studied. The properties of the scaffolds were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), contact angle analysis, and biomechanical testing. To verify the biocompatibility of the scaffolds, the viability, proliferation, and extracellular matrix (ECM) production of the cells seeded on the scaffolds were assessed by LIVE/DEAD staining, Cell Counting Kit-8 assay, biochemical content analysis, immunofluorescence staining, and qRT-PCR. The functionalized hybrid scaffolds were then implanted into the subcutaneous space of nude mice for 6 weeks, and the regenerated tissue was evaluated by histological staining. The biomechanical properties of PCL/PU and PU scaffolds were comparable to that of the central and peripheral zones, respectively, of a native human TMJ disc. The PDA-coated scaffolds displayed superior biomechanical, structural, and functional properties, creating a favorable microenvironment for cell survival, proliferation, ECM production, and tissue regeneration. In conclusion, 3D-printed polymer scaffolds coated with PDA and combined with dECM hydrogel were found to be a promising substitute for TMJ disc tissue engineering.