Regression models of individual cephalometric indicators used in the method of E.P. Harvold
Authors: Chernysh A.V. , Hasiuk P.A. , Yasko V.V. , Smolko D.G. 
Published: May 2019

Many scientific studies have shown the superiority of the Harvold method when performing linear measurements for both the upper and lower jaw. The purpose of the work is to construct and analyze the regression models of teleroentgenographic indices used in the method of E.P. Harvold young men and women with normal occlusion close to orthognathic bite and harmonic face. The analysis of lateral teleroentgenograms of 38 young men (aged from 17 to 21) and 55 young women (aged from 16 to 20 years) with normal occlusion close to orthognathic bite and harmonic face, obtained using the Veraviewepocs 3D device, Morita (Japan), was performed according to the techniques of R.M. Ricketts, C.J. Burstone, E.P. Harvold. In the course of the study, all the indicators of the above methods, were divided into three groups: 1 – metric characteristics of the skull, which usually do not change during surgical and orthodontic treatment; 2 – indicators of the tooth-jaw system that allow people with already formed bone skeleton to 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. In the licensed package “Statistica 6.0”, regression models were constructed for the following parameters included in the second group, depending on the parameters of the first group: ANS-Сond (maxillary length in the Harvold method described as TM-ANS), Pog-Cond (mandibular length in the E.P. Harvold method is indicated as TM-PGN), Max-Mand – (difference in jaw lengths); as well as the index included in the third group, depending on the indicators of the first and second groups – Ap1uAp1l-DOP (angle Ap1uAp1l-DOP). In the young men, all three possible reliable models of teleroentgenographic parameters were constructed using the E.P. Harvold method, which were included in the second group, depending on the indicators of the first group (R2 = from 0.616 to 0.940), and in young women only the length of the upper and lower jaws (R2=0.857 and 0.792). In both young men and women, all models of the second group of models built according to the indicators of the first group included the distance P-PTV. Up to two models for young men and one model for young women included the distance Pt-N. Also, one model for young men and women included the angle of the cranial tilt (POr-NBa). Only young women have models for the front length of the skull base (N-CC). As for young men and women, we also built a reliable model of the third group indicator, depending on the indicators of the first and second groups (the angle Ap1uAp1l-DOP) (respectively, R2=0.626 and R2=0.584). And in young men and women, the size of the distance A-B is included to the constructed regression equations. In addition, in young men, the regression equation includes the value of the distance P-PTV; while in young women - the angles of the ANS-Xi-PM, MeGo-NPog and N-CF-A, as well as the difference in jaw lengths Max-Mand.