Skull measuring methods in the analysis of temporo-mandibular joint tomography in man

Aim of research: development and substantiation of method of analysis of temporomandibular joint (TMJ) tomographic image by craniometric points. Material and methods. Imaging of TMJ elements was performed with the use of lateral target linear tomography. Depth of slice was determined according to the palpable lateral orbital border. Central ray was targeted 1 cm above and anteriad from the external auditory canal. Focal distance of the tube was 100 cm. Cassette 13x18 cm was positioned in transverse direction. Physical and technological conditions of imaging: tube voltage 57-63 kV; current intensity 60100 mA; focal distance 110-120 cm; exposure 2 s; angle of tube shifting during tomography 30°. Two images were taken on 13x18 film positioned in transverse direction: “mouth closed” and “mouth opened”. 56 tomographic images from 28 women aged 36-45 with TMJ dysfunction were studied. Evaluation of all tomographic images was performed simultaneously with the use of Ryabukhina’s method (1966) as well as craniometric points. On scanned images craniometric points on TMJ bone elements were determined by the method developed by the authors using PARAGONE software with the help of Adobe Photoshop. According to craniometric points, cephalometric planes and angles are formed and the character of geometric correlation between TMJ elements is determined. Results and conclusions. On analyzing TMJ tomographic images it is better to use not the view of cranial bones contours, but the centers of their tomographic cross-section as a craniometric point. Angular readings, in contrast to linear ones, are more reliable for characterization of joint function. Metrical analysis of the width of roentgen joint space based on the craniometry by external contours can’t characterize intra-articular correlations.