ABSTRACT
THE AIM OF THE STUDY: Was determination of TMJ anatomical and functional parameters in patients without clinical manifestations of TMJ dysfunction and analysis of possible relationships between them. MATERIAL AND METHODS: TMJ anatomical parameters of 25 volunteers (22-27 years old) without TMJ dysfunction, malocclusion and more than one tooth adentia were determined on CT scans and lab teeth scans: inclination of the distal slopes of the articular eminence (DS AE), height and width of the condyles, height of AE, inclination of the longitudinal axes of the condyles; as well as functional parameters of LJ movements: horizontal condylar inclination (HCI) during protrusion and laterotrusion, lateral condylar inclination during protrusion and laterotrusion, immediate side shift, incisor and canine guidance, and correlations between them were evaluated. RESULTS: The majority of the TMJ anatomical parameters are almost equal by mean values on the right and left sides. The main TMJ functional parameters on the right and left sides also have similar values but much higher variability, asymmetry and unpredictability. The existing anatomical asymmetry of the DS AE is compensated by articular discs, which makes HCI more symmetrical. CONCLUSION: Protrusion movements have a higher probability of reproduction by mechanical articulators while laterotrusion movements have a very low probability. The existence of relationship between the inclination of DS AE and HCI, between HCI and the incisor guidance, between the inclination of DS AE and the incisor guidance is questionable. The conducted research proves the weakness or complete absence of correlation between them.
Subject(s)
Temporomandibular Joint Dysfunction Syndrome , Temporomandibular Joint , Dental Occlusion , Humans , Incisor , Mandibular Condyle/diagnostic imaging , Temporomandibular Joint/diagnostic imagingABSTRACT
OBJECTIVE: The main aim of the study is devoted to optimization of the technique of 3D analysis of TMJ parameters, analysis of the causes of possible errors. MATERIALS AND METHODS: The technique of 3D analysis of the width of the articular gap, the size of the condyle, the height and slope of the distal slope of the articular tubercle in the Avantis3D software (Russia) according to computed tomography is presented. The influence of repeated manual corrections of the condyles and articular fossa contours, shifting of the sectors measuring center, the position of starting point of the measurement sectors, and different algorithms for determining the longitudinal axis of the condyles on the accuracy of TMJ parameters detection. RESULTS: The study showed that any artificial displacement of the center of measurement sectors, which coincides with the longitudinal axis of the condyle, leads to significant value changes of the parameters. In this regard, the exact determination of the longitudinal axis of the condyles, independent of the human factor, is of particular importance. The greatest inaccuracy and variability of the results of measuring the parameters of the TMJ, as shown by the study, is associated with the possible manual correction of the contours of the surfaces of the condyles and articular fossa. The study did not find a noticeable difference in measurements if the sectors starts from the top of the articular tubercle or from the line parallel to the Frankfurt horizontal. As the optimal settings of the developed method was determined, it was used to determine the average values of the TMJ parameters for patients with a conventional «norm¼, as well as for patients with TMJ dysfunction. A noticeable and statistically significant difference was found between the groups only for upper and posterior width of the joint space. CONCLUSION: The average values of the intra-articular spaces width were justified, and can be used as the basis for the virtual assignment of the lower jaw reconstructive position for prosthetic or orthodontic treatment.
