Regression models of individual cephalometric indicators used in the method of R. M. Ricketts
Authors: Chernysh A. V. 
Published: March 2019

It is proved that in the analysis of lateral teleroentgenograms according to different methods distances and angles have their normative indices which differ for persons of different ethnic, gender and age belongings. Therefore, for a full use in the orthodontics R.M. Ricketts method, similar studies are needed in Ukraine. The purpose of the work – in young men and women  with normal occlusion close to the orthognathic bite and harmonious face construct and analyze the regression models of teleroentgenographic indicators used in the method of R. M. Ricketts. Primary lateral teleroentgenograms of 38 young men (aged 17-21 years) and 55 young women (aged from 16 to 20 years) with normal occlusion close to orthognathic bite and harmonic face, obtained from the Veraviewepocs 3D device, Morita (Japan), taken from the bank data of research center of National Pirogov Memorial Medical University, Vinnytsya. Cephalometric measurements were performed according to the recommendations of R. M. Ricketts. All indicators were divided into three groups: 1 - metric characteristics of the skull, which usually do not change during surgical and orthodontic treatment; 2 – tooth-jaw indicators, the definition of which most often guided by performing orthodontic manipulations of patients in children and adolescents, as well as those with already formed bone skeleton when orthodontic surgery can change the width, length, angles and position of the bones of the upper and lower jaws; 3 - indicators that characterize the position of each individual tooth relative to each other, to the bony cranial structures and face profile. The regression models of individual teleroentgenographic indicators used in the R.M. Ricketts methodology are constructed using the “Statistica 6.0” licensing package. Constructed all 2 reliable models of the indicators included in the second group (distance Go-CF and Xi-Pm), depending on the indicators of the first group (in young men R2 = 0.884 and 0.928, and in young women - 0.735 and 0.719); as well as in young men, 7 out of 8 possible reliable models (R2 = from 0.568 to 0.887) of the indicators included in the third group (the magnitude of the distances 6u-6l, Overjet, Overbite, 6u-PTV, 1l-APog, 1u-APog and Xi-OcP ) depending on the indicators of the first and second groups; and only 5 models for young women (6u-PTV, 1l-APog, 1u-APog and Xi-OcP distances, and the magnitude of the Max1-APog angle). In the analysis of entering into the regression models of the relevant predictors, it was found that in young men, among the teleroentgenographic indicators of the first group included in the two models of the second group, is the distance P-PTV, and in young women the front length of the base of the skull N-CC and the back of the skull base Ar- Pt It was also found that among young men among the teleroentgenographic indicators of the first and second groups, which were included in the models of the third group, the most frequent is the value of the distance B-Pog (11.1%); while in young women - distance B-Pog (15.6%) and an angle DC-Xi-PM (9.4%).