Morphometric features of dental arches in the period of mixed dentition

Abstract

Based on the results of a biometric study of plaster models of the jaws obtained in 38 children in the period of early mixed dentition (8–9 years old) with a neutral location of the first permanent molars and optimal incisal overlap corresponding to the optimal functional occlusion of this age category, the limits of variability of the dental arcade index were calculated arcs with macro-, micro- and normodental type of the dental system. The total value of the width of the crowns of 12 teeth in children in the period of early mixed dentition from 92 mm to 97 mm in the upper jaw and from 85 mm to 90 mm in the lower jaw is an indicator of the normodontic type of the dental system, while the length of the dental arch is less than 92 mm in the upper jaw and 85 mm on the lower jaw indicates that such arches belong to microdont ones, and more than 97 mm on the upper jaw and 90 mm on the lower jaw – to macrodont ones. In the early period of mixed dentition, the value of the arcade index, as the ratio of the width of the dental arch to its length, in the range from 0.57 c.u. up to 0.64 c.u. is an indicator of the mesoarcade type of dental arches, and an increase (more than 0.64 a.u.) or a decrease (less than 0.57 a.u.) of this value indicates that the dental arches belong to the brachiarcade or dolichoarcade types, respectively. When constructing a dental diagnostic triangle in children with anomalies in the shape of the dental arches in the early removable dentition, it is advisable to take into account that the value of the incisor-molar diagonals is established not by determining linear parameters, but by calculating the ratio of the length of the dental arch to the value of the diagonal correction factor (upper jaw – 1 .05; lower jaw – 1.07).