Cephalometric Landmark of a Midsagittal Plane of the Temporomandibular Joint in the Structure of Diagnostic Criteria for Temporomandibular Disorders

Abstract

The purpose of this study was to establish a methodology for determining the midsagittal plane of the temporomandibular joint (TMJ) via the cephalometric landmarks in the structure of diagnostic criteria for temporomandibular disorders.Study Design: Cephalometry of 20 human skulls was obtained. Targeted linear tomography of the TMJ was obtained in a lateral projection. Statistical processing included descriptive methods. Frequencies of the level of the midsagittal plane of the temporomandibular joint are presented.Results: Using cephalometry, we found the midsagittal plane of the frontal process of zygomatic bone (lateral orbital wall) to correspond to the midsagittal plane of the TMJ, parallel to the midsagittal plane of the skull. The lateral orbital wall of the skull was projected onto the lateral rim of the angle of the eye. The distance between lateral orbital rims was the distance between midsagittal planes of the TMJ heads. To check cephalometric results, we used the method of targeted linear TMJ tomography. According to anatomical landmarks, the depth of the tomographic slice at the midsagittal plane of the TMJ level was defined. In total, 176 patients were examined, and 604 tomograms were studied. Images of excellent and good quality were obtained in 94.2% of cases. The depth of tomographic slices in 86.7% of studies ranged from 2.0 to 3.0cm (in 42.2% of observations, 2.5cm; in 21.6% of observations, 2.0cm; in 22.9% of observations, 3.0cm). Conclusion:The lateral orbital wall can be used as a cephalometric landmark defining the midsagittal plane of the TMJ. The resulting landmark makes it possible to determine the individual depths of tomographic slices, to calculate the distance between heads of the mandibular jaw, and to plan treatment in reconstructive maxillofacial surgery, orthodontics, and orthopedics.