Physiological Tooth Migration and its Significance for the Development of Occlusion

Abstract

A study of the developmental changes of the deciduous dentition was made of 30 children from 3 to 5.5 yrs. of age by means of plaster reproductions. Serial measurements and examination showed that after the deciduous arches were fully formed their sagittal and transversal dimensions (measured from points not affected by attrition) were not altered except when subjected to inadequate environmental influences. Two morphological arch forms were observed; the deciduous dental arches were either continuously spaced or continuously closed. Closed arches were on an avg.. narrower transversally than spaced ones. The interproximal spaces were not developmental but congenital. The spaced arches frequently showed 2 distinct diastemata, one between the mandibular deciduous canine and 1st deciduous molar and the other between the maxillary deciduous 2d incisor and deciduous canine; they were called "primate spaces." The terminal plane of the arches in occlusion constantly remained straight in 80%,and in 15% formed a mesial step. None of the observations made in this study could corroborate the concept of physiologic changes of the deciduous dental arches through spacing and mesial shifting of the mandibular teeth.