The morphologic characteristics of Class I, non-extraction patients

Chang, Young Il; Shin, Soo Jung

Abstract

The purpose of this study was to investigate the pretreatment and posttreatment dentofabial characteristics of non-extraction patients with Class I malocclusion. And to compare this result with matched non-orthodontic normal occlusion and Class I premolar extraction patients. Such comparison might help identify morphologic characteristics of the non-extraction patients. Initial and final cephalometric evaluation were compared in a sample of 22 patients with Class I malocclusions treated in non-extraction manner with edgewise appliance and MEAW. The mean age of the total population was 14 years 9 months and the average treatment time was 2 years 8 months. 32 landmarks were located and digitized on each cephalogram. From these landmarks, 24 linear and angular dimension were obtained Student's t-test were used to compare the pretreatment - posttreatment results, Nonextraction - Normal groups, and nonextraction - Extraction groups. Significance was predetermined at p < or = 0.05. The results were gas follows. 1. Before treatment, the mean value of the ODI was 69.9degrees, APDI was 82.1degrees, CF was 152degrees, and El was 152degrees in the non-extraction groups. 2. The skeletal pattern of the non-extraction groups were similar with non-orthodontic normal group3, but the non-extraction groups had larger interincisal angle. 3. Comparison between groups treated with and without extraction indicated at pretreatment, the extraction groups had more protrusive lips, smaller interincisal angle, and El. 4. After treatment, there was no significant changes in the skeletal pattern of the non-extraction groups, but uprighting of the maxillary and mandibular first molar and decrease of the interincisal angle were seen.