A clinical and X-ray analysis of temporomandibular joint bone elements ratio in children and adolescents with distal position of lower jaw

Abstract

Aim to conduct a clinical and radiological analysis of the temporomandibular joint (TMJ) bone elements ratio in patients of 1217 years old with a distal position of lower jaw.
 Material and methods. We examined 122 patients of two age groups: 1215 years old and 1517 years old. Patients with malocclusion class II formed the main group, the control group consisted of patients with physiological occlusion. Depending on the diagnosis, the patients of the main group were divided into subgroups in accordance with Angle's classification of malocclusion: patients with class II, subclass 1; patients with class II, subclass 2. The TMJ tomograms were analyzed according to the method of N.A. Rabukhina and the method proposed by the authors. The results were compared in patients from different groups.
 Results. The size of the TMJ space in the anterior section in patients with class II subclass 1 malocclusion increases with age from 2.440.14 mm to 2.960.17 mm, P = 0.048, P = 0.008 in comparison with patients with physiological occlusion. In patients with class II subclass 2 the TMJ space increases from 2.920.21 mm to 3.120.19 mm (P = 0.001). In patients with class II subclass 1 in the age group of 1215 years, the value of the angle in habitual occlusion is increased to 20.011.01 on the right (P = 0.035), and to 20.781.11 on the left (P = 0.044). In the group of 1517 years the value of the angle ⟨ is reduced to 16.331.15 on the right (P = 0.04) and to 16.930.93on the left (P = 0.049). In patients with class II subclass 2 malocclusion in the age group of 1517 years, the value of the angle on the right is reduced to 16.471.02 (P = 0.016), on the left to 16.030.86 (P = 0.011). The revealed differences indicate violations of ratio of the TMJ bone elements with age in patients with malocclusion class II. The asymmetry and distal position of the mandibular heads in the TMJ are most prominent in the subgroup of patients with class II subclass 2 malocclusion.
 Conclusion. The method of analyzing angular indicators on the TMJ CBCT data complements the study of the TMJ CBCT data according to the method of N.A. Rabukhina.