Normal temporomandibular joint structure and function determined by ultrasound

Purpose. The purpose of this study was to determine ultrasound criteria of normal temporomandibular joint structure and function. Materials and methods. Prospective study was conducted upon normal 16 TMJs of 9 patients (4 male, 5 female with mean age of 22.9 years) without clinical or radiological signs of disc displacement. All the patients underwent high-resolution ultrasound (Samsung SONO ACE R3, 12 MHz linear probe) and MR imaging of TMJs with the mouth closed and during the maximal mandibular range of motion. Both examinations were performed and interpreted independently by blinded expert operators. Results. Mouth opening range varied from 4.4 cm to 5.4 cm, average amount was defined as 4.94 ± 0.39 cm. Also average heights of the front, middle and rear parts of disc were measured (0,42 ± 0,07 cm; 0,35 ± 0,07 cm and 0,41 ± 0,05 cm, respectively). Structure of the TMJ disc can be defined as fine-grained, hypoechoic and homogeneous. The average height of lower joint space was defined as 0,12 ± 0,03 cm. Average amount of maximal parasagittal mandible condyle movement was defined as 14.7 ± 1.38 mm. Conclusion. Obtained results of ultrasound criteria of normal temporomandibular joint structure and function correspond to the provisions of normal human anatomy and the norm values established for the MRI of the TMJ. Thus, ultrasound criteria of normal temporomandibular joint can be used for assessment of TMJ internal degenerative diseases. © 2018 Russian Electronic Journal of Radiology. All rights reserved

Correction of internal disorders of the temporomandibular joint using muscle relaxation splints made with CAD/CAM technologies

The aim of the study was to evaluate possible applications of muscle relaxation splints made with a milling method (with CAD/CAM technologies) for correction of the temporomandibular joint (TMJ). Materials and Methods. We studied 47 patients with TMJ disc displacement with reduction that causes the lower jaw articulation disorders. All patients underwent axiographic investigation before, in the course of (every 3 weeks), and after the treatment. In group 1 (n=22) we used muscle relaxation splints made in a mechanical articulator, in group 2 (n=25) splints were modeled in a virtual articulator in accordance with axiographic findings. Results. The results of treating patients with subluxation of the TMJ articular disc with muscle relaxation splints made with mechanical and virtual articulators showed that the use of a virtual articulator resulted in minimal frequency of positioning errors in the articulator interframe space. The study also revealed that higher accuracy of location of virtual models in accordance with an individual location of joint mechanisms of an articulator. We developed a method of loading individual joint trajectories of the lower jaw when the articulation of the latter is impaired. It helped to considerably reduce inaccuracies of splint modeling that occur when a standard mechanical face bow made with mechanical articulators is used. Conclusion. For patients with TMJ disc displacement with reduction treatment with milled splints made in a virtual articulator is more preferable. The developed algorithm of loading individual joint trajectories of the lower jaw movements and occlusion contacts according to axiographic findings during the process of modeling muscle relaxation splints can enhance the quality of treating patients with dearticulation. © 2019, Privolzhsky Research Medical University. All rights reserved

Normal temporomandibular joint structure and function determined by ultrasound

Purpose. The purpose of this study was to determine ultrasound criteria of normal temporomandibular joint structure and function. Materials and methods. Prospective study was conducted upon normal 16 TMJs of 9 patients (4 male, 5 female with mean age of 22.9 years) without clinical or radiological signs of disc displacement. All the patients underwent high-resolution ultrasound (Samsung SONO ACE R3, 12 MHz linear probe) and MR imaging of TMJs with the mouth closed and during the maximal mandibular range of motion. Both examinations were performed and interpreted independently by blinded expert operators. Results. Mouth opening range varied from 4.4 cm to 5.4 cm, average amount was defined as 4.94 ± 0.39 cm. Also average heights of the front, middle and rear parts of disc were measured (0,42 ± 0,07 cm; 0,35 ± 0,07 cm and 0,41 ± 0,05 cm, respectively). Structure of the TMJ disc can be defined as fine-grained, hypoechoic and homogeneous. The average height of lower joint space was defined as 0,12 ± 0,03 cm. Average amount of maximal parasagittal mandible condyle movement was defined as 14.7 ± 1.38 mm. Conclusion. Obtained results of ultrasound criteria of normal temporomandibular joint structure and function correspond to the provisions of normal human anatomy and the norm values established for the MRI of the TMJ. Thus, ultrasound criteria of normal temporomandibular joint can be used for assessment of TMJ internal degenerative diseases. © 2018 Russian Electronic Journal of Radiology. All rights reserved