Correlation of TMJ structures and craniocervical area position in partial dental loss

: The purpose of the study was to determine the correlation features in position of the TMJ and the atlantoaxial compound in presence of dentition defects. The study included 20 patients (10 males and 10 females) aged 37 to 59 years with mandible terminal dentition defects. The comparison group included 20 patients of men and women equally, aged from 18 to 29 years with intact dentition. All patients were diagnosed with CT scan of the maxillofacial area, including the craniovertebral zone. In the analysis of the TMJ, the ratio of bone structures were determined by studying the CT scan in sagittal plane. The position of the elements of the atlantoaxial compound were evaluated on CT scan in frontal and transversal plane along the distance from the lateral masses of the CI vertebrae to the dens CII process. In persons with one-sided terminal dentition defect any changes of the position of the TMJ elements were not determined except for the right L1 parameter (8.91±0.45 mm and 6.8±0.77 mm, respectively, p=0.020). At the same time, the L1 distance on the left significantly changed to 6.86±0.40 mm relative to the comparison group (8.21±0.77 mm, p=0.030). In contrast to the ratio of the bony structures of the TMJ on the analysis of the craniocervical zone we determined the differences in the relationships of all elements of the atlantoaxial compound. The asymmetry index of CI-CII in the study group was 1.12±0.15 mm, in the comparison group 0.1±0.02 mm, p=0.001. The correlation analysis of the investigated structures showed different variants of the relation (direct and inverse) between the L1, L5 parameters of the TMJ and the distance from the lateral masses CI to dens CII. The structures of the TMJ in the presence of dentition defects remain practically unchanged and are more stable, it can be assumed that the primary link which undergo the changes considering the relationship between bone structures is the atlantoaxial junction.