Modeling the parameters necessary for constructing the correct shape of the dental arch depending on the features of teleradiometric indicators using the Steiner or Tweed methods and computed tomography dimensions of teeth

The study of the parameters of the dental arch, taking into account teleradiometric indicators and tooth sizes, is important for planning orthodontic treatment, which contributes to achieving stable and functionally optimal results. The Steiner and Tweed methods, widely used to assess craniofacial proportions, allow identifying key anthropometric features that affect the shape of the dental arch. The additional use of computed tomography measurements provides high accuracy in analyzing tooth sizes, which is especially important for individualizing orthodontic approaches. The aim of the work is to build and analyze regression models of parameters necessary for constructing the correct shape of the dental arch in Ukrainian young men and young women with physiological occlusion, depending on the features of teleradiometric indicators according to the Steiner or Tweed methods and computed tomography sizes of the teeth. On standardly obtained teleradiograms and created in the 3D Slicer v5.4.0 software on teleradiograms with points marked on 3D objects (41 Ukrainian young men and 68 young women with physiological occlusion from the data bank of the Department of Pediatric Dentistry and the Scientific and Research Center of the National Pirogov Memorial Medical University, Vinnytsya), measurements according to the Steiner S. S. and Tweed C. H. methods were carried out in the OnyxCeph³™ application, version 3DPro, from Image Instruments GmbH, Germany. On computer tomograms for morphometric study of teeth and dental arches we used software applications i-Dixel One Volume Viewer (Ver.1.5.0) J Morita Mfg. Cor, and Planmeca Romexis Viewer (ver. 3.8.3.R 15.12.14) Planmeca OY. Regression models were built using the licensed package “Statistica 6.0”. It was found that in young men, taking into account the Steiner method, all 18 possible reliable models with a coefficient of determination greater than 0.6 were built (R2= from 0.611 to 0.911, p<0.001), and taking into account the Tweed method, 17 models (R2= from 0.638 to 0.872, p<0.001); and young women – only 5 reliable models with a coefficient of determination greater than 0.6 when taking into account the Steiner method (R2= from 0.613 to 0.782, p<0.001) and only 4 reliable models when taking into account the Tweed method (R2= from 0.619 to 0.745, p<0.001). When analyzing the frequency of occurrence in the regression equations of computed tomography sizes of teeth and teleradiometric indicators according to the Steiner or Tweed methods, it was established: in young men, the width of the crown part of the tooth in the mesio-distal and vestibulo-oral planes, the length of the tooth in the mesio-distal and vestibulo-oral planes and teleradiometric indicators are most often included in the models; and in young women: when taking into account the indicators according to the Steiner method - the width of the crown part of the tooth in the mesio-distal and vestibulo-oral plane and teleradiometric indicators; when taking into account the indicators according to the Tweed method - the width of the crown part of the tooth in the mesio-distal and vestibulo-oral plane, the length of the tooth in the mesio-distal and vestibulo-oral planes, teleradiometric indicators and the length of the crown part of the tooth in the mesio-distal plane. When analyzing the frequency of occurrence in the regression equations of the corresponding teeth, it was found that in young men, the models that take into account the teleradiometric indicators according to the Steiner or Tweed methods most often include the upper and lower incisors, upper and lower premolars and upper canines; and in young women – upper and lower incisors, upper and lower canines, lower premolars and upper first molars taking into account teleradiometric indicators according to the Steiner method, as well as upper and lower incisors and lower premolars taking into account teleradiometric indicators according to the Tweed method.