摘要：O BJECTIVE : The aim of this retrospective study was to evaluate the short- and long-term effects of mandibular incisor movement due to non-extraction treatment on dimensions of mandibular symphysis (MS). M ATERIALS AND M ETHOD : Lateral cephalograms (before treatment, TB; after treatment, TS; retention, P) of 20 females classified as skeletal class 1 (ANB:0-4°), dental class I and having an optimal vertical growth direction (SN/GoGN: 32±6°) were selected from the archive of the Department of Orthodontics, Faculty of Dentistry, Gazi University. These subjects had mean chronological age of 14.9±3.3 years and mean mandibular crowding of 2.6±1.7 mm. On the cephalograms, 7 angular, 11 linear measurements were done in order to determine skeletal characteristics, position of the mandibular incisor and dimensions of MS. The width of MS and the amount of bone around the mandibular incisor were determined at three levels (crest ridge, center of rotation and root apex of the incisor). Statistical analyses were performed by using One-Way ANOVA to evaluate intergroup differences followed by a post-hoc Tukey test. Correlation analyses were performed by using Pearson correlation test (p<0.05). R ESULTS : Mandibular incisor protruded significantly with treatment (Co/1°, 1/MP°: p<0.05; 1/NB°, 1-NB: p<0.01) and bone thickness at crest ridge level was significantly lower at TS (p<0.05) and at P (p<0.001) when compared to TB. However, bone thickness at the center of rotation and root apex, and the MS height were not affected from treatment (p>0.05). There were no correlations between age at TB, total treatment time, amount of crowding and mandibular incisor protrusion with changes in crest ridge bone thickness (p>0.05). C ONCLUSION : The mandibular incisor protrusion seen after non-extraction treatment caused a decrease in bone thickness at the crest ridge level, and it was maintained at the retention period.
关键词：Malocclusion, angle class I;mandibular symphysis;orthodontics;Maloklüzyon, angle sınıf 1;mandibular simfiz;ortodonti
