A study on the regularity of center of rotation in the orthodontic treatment of embedded and inverted impact upper central incisor / 实用口腔医学杂志

ABSTRACT

Objective: To study the influence of different inhibition conditions for center of rotation (CR) and regularity variations of CR before and after orthodontic treatment of embedded and inverted impact upper central incisor. Methods:Based on clinical findings a computer model of rolling movement was established,then computer finite element Super DrawnⅡwas applied to establish an analytic analogue computing model for calculation. Results:The deeper the crown embedded by hard tissue,the more the edgewise displacement of CR;while the crown was normally exposed,the moving locus tended toward front and upward. Conclusions: Perpendicular orthodontic force to the long axis of tooth forced point that close to the incisal margin and the partly embedded crown by the alveolar bone,especially the bone of lingual aspect are the main factors for the upward moving and erectness of the root apex. Possible subsidence of CR may be avoided by suitable early stage orthodontic treatment.