6전치 일괄(en masse)견인과 견치 견인 후 4전치 견인 시 공간폐쇄 양상에 관한 연구

A comparison of en masse retraction of six anterior teeth with separate canine retraction

The purpose of this study was to compare en masse retraction of six anterior teeth with separate canine retraction in the amount of the anchorage loss and the retraction of the anterior teeth. The subjects consisted of 30 adult female patients with Angle Class I malocclusions who were treated by .022 straight wire appliance with 4 first premolar extraction. They were composed of two groups. Group 1 consisted of 15 subjects, whose six anterior teeth were retracted by en masse retraction. Group 2 consisted of 15 subjects, whose canines were retracted separately. Pre-treatment and post-treatment lateral cephalometric radiographs were analyzed. All data were processed statistically with independent samples t-test, and the conclusions were as follows. 1. There was no significant difference in the amount of the anchorage loss between two groups(p>0.05). 2. There was no significant difference in the amount of the retraction of the anterior teeth between two groups(p>0.05). 3. There was a significant difference in the amount of the inclinational change of the upper incisors between two groups. It was greater in Group 2. 4. There was a significant difference in the vertical positional change of the upper incisal edges between two groups. The upper incisal edges in Group 2 were more extruded than Group 1 by about 1 mm. 5. There was no significant difference in the vertical positional change of the root apex of the upper incisors between two groups(p>0.05). And there was no significant difference in the vertical positional change of the upper molar(p>0.05).