Abstract
The aim of the work: The aim of the study was to outline the procedure for changing the transverse dimensions, which orthodontists could use in practice. Another goal was to detect transverse discrepancy (difference in the skeletal height of the upper and lower teeth and the inclination of all first molars) using CBCT in patients with I. skeletal tibia. The last goal was to find out if these values differ in patients with different vertical parameters.
Material and methodology: The group included 152 patients, of whom 24 had unilateral lateral malocclusion and 9 bilateral lateral malocclusion. All scans were taken on the same NewTom VGi-Evo instrument (manufactured by QR srl, Verona, Italy) with a FOV of 16 x 16 cm. The group included boys and girls with an average age of 14 years who had not undergone orthodontic treatment in the past and had skeletal class I according to the ANB and WITS angle values and Angle's class I in molars. Subjects underwent a standard cephalometric analysis in the graphic module of the PC Dent program (CompuGroup Medical, Czech Republic) from the lateral cephalometric image created from the CBCT scan, and the values of NSML and vertical anterior and posterior lateral heights (SGo/NMe x 100). From the CBCT images, linear and angular parameters were then used to determine the dental and skeletal transverse discrepancy.
Results: A statistically significant difference was demonstrated between boys and girls only in the normodivergent groups in the angle of the lower first molars. A statistically significant difference in the angle of the lower molars was found between the individual types of vertical divergence of the tooth bases in the hyperdivergent group compared to the hypodivergent group. The individual groups (A, B, C, D, E) differ statistically significantly in the values of the vestibulooral inclinations of the upper molars, in the skeletal height of the lower elist and in the difference in the height of the skeletal bases.
Conclusion: Discrepancy in the transverse dimensions of the teeth may not only be associated with a laterally misaligned bite, but may also occur in patients with apparently normal molar proportions. The vestibulooral inclinations of the first molars allowed compensation of the skeletal basis of the transverse discrepancy.