Український стоматологічний альманах (Mar 2016)
THE STUDY OF THE DENTITION DEFECTS, THE INFLUENCE ON THE TEMPOROMANDIBULAR JOINTS DISCS OF ANATOMICAL CHARACTERISTICS DUE TO THE RESULTS OF MORPHOLOGICAL INVESTIGATION
Abstract
This work concerns the improvement of diagnosis quality of the internal disorders temporomandibular joints (TMJ) by means of determining the dentition defects influence on morphological peculiarities of articular discs. • articular discs obtained from the anatomical blocks with TMJs (50 pairs), extracted by the special method in the course of autopsy investigation in adults, served as the subject of scientific research. In addition to that, in each case, the pairs of teeth-antagonists which were preserved on both left and right sides of jaws in deceased persons were determined (the fixed orthopedic constructions in areas of occlusive support were taken as the preserved dental supports). Micrometer was used to measure: the thickness of anterior and posterior cartilaginous toruli of discs (in sagittal plane that passes through their geometric centre), the thickness of the central part of discs, the thickness of the cartilage on the medial and lateral poles of discs. Slide gauge was used to measure the distance between the lateral and medial poles of discs, when they were still attached to articular heads at the time of opening of the TMJ upper chamber. The disposition of cartilaginous tissue predominating volume of discs with regards to TMJ heads was determined by visual examination and palpation. In order to study, the influence of present dentition defects with a variable loss of occlusive support areas on anatomical characteristics of TMJ discs, the selected discs were divided into the control group and three experimental groups taking into consideration the presence of teeth-antagonists pairs in the molars area, premolars area and in the frontal teeth area on the side of extracted TMJs. Thus, 15 discs were referred to the control group (available pairs of teeth-antagonists in the molars, premolars and in the frontal areas on the side of extracted discs). 16 discs were referred to the first experimental group (available pairs of teeth-antagonists in the premolars and in the frontal areas on the side of extracted discs). 18 discs were referred to the second experimental group (available pairs of teeth-antagonists solely in the frontal teeth area on the side of extracted discs). 51 disc were referred to the third experimental group (no pairs of teeth-antagonists on the side of extracted discs). It was calculated: the arithmetical mean value of the distance between the lateral and medial poles of discs, the thickness of anterior and posterior cartilaginous toruli of discs, the thickness of the central part of discs, the thickness of the cartilage on the medial and lateral poles of discs for the control group (Mc) and for three experimental groups (Mex1, Mex2, Mex3). Student's t-test criterion with Bonferroni’s correction was also calculated for each paired comparison (t1 – comparison of the first experimental group and the control group, t2 - comparison of the second experimental and control groups, respectively, t3 - comparison of the third experimental and control groups, correspondingly). On comparing the t-critical value with the calculated t (t1, t2, t3) for all the above-mentioned anatomical characteristics of discs, it was revealed that the t-critical value was higher than that of the calculated ones. Thus, the difference between the experimental groups and the control group is non-valid (p>0,05). Therefore, the influence of the dentition defects with variable loss of occlusive support areas on the distance between the lateral and medial poles of discs, on the thickness of anterior and posterior cartilaginous toruli of discs, on the thickness of the central part of discs, on the thickness of the cartilage on the medial and lateral poles of TMJ discs on the side of the defects is insignificant. As to the localization of cartilaginous tissue predominating volume of discs with regard to the TMJ heads, it was revealed either closer to medial pole (in 56,70±5,03% cases among all those selected), or it was evenly distributed above the head (43,30±5,03%). The percentage of different localization of the cartilaginous tissue predominating volume of articular discs with regard to the TMJ heads in the control group (Pc) and in three experimental groups (Pex1, Pex2, Pex3) were calculated. It was revealed that the parts don't differ considerably both in the first and the third experimental groups, but these two groups differ strongly from both the control group and the second experimental one. In order to ascertain whether the present difference is valid, the criterion χ² was calculated (χ²=9,54). The critical value of χ²=7,815. The calculated criterion χ² (9,54) is larger than the critical value χ² (7,815). Thus, the difference between the compared groups is proved to be valid (p<0,05). Consequently, the significant influence of present dentition defects with a variable loss of occlusive support areas on localization of cartilaginous tissue predominating volume of articular discs with regard to the TMJ heads on the side of defects was established, which is more likely indicates on compensatory response of the disc.
