Changes in the vertical position of the anterior teeth after surgical correction of mandibular protrusion

Abstract

The intention of this study was to evaluate the effect of the vertical forces acting during the intermaxillary fixation period, by studying the changes in the length of the clinical crowns of the upper and lower anterior teeth, by measuring the height of the interproximal marginal bone ridge pre- and postoperatively, by studying the amount of apical root resorption, and by measuring the change in the distance from the maxillary and mandibular bases to the edges of the upper and lower incisors. Tooth extrusion was also related to changes in the inclination of the mandible, and the interrelationship between tooth extrusion and apical root resorption was recorded. The material comprised models, lateral cephalograms, and standardized intraoral roentgenograms of fifty-six patients taken immediately before the surgical correction of the mandibular protrusion and 2 years postoperatively. The results displayed an increase in clinical crown height of 0.2 to 0.7 mm. The root length was reduced from 0.5 to 0.9 mm. There was no change in the height of the marginal ridges. A linear correlation analysis did not show any significant correlation between the shortening of the roots and the lengthening of the clinical crowns or between the change in inclination of the mandible and the increase in crown height. The increase in the distance from the maxillary and mandibular bases to the incisor edges of the upper and lower incisors did not reveal any significant correlation with the change in mandibular inclination, crown height, or root length.