A study on the morphological changes of lower incisor and symphysis during surgical-orthodontic treatment in skeletal class III malocclusion

Ahn, Hyung Soo; Kim, Seong Sik; Son, Woo Sung

Abstract

The purpose of this study was to evaluate the morphological changes of alveolar bone and mandibular symphysis of lower incisor by presurgical orthodontic treatment and orthognathic surgery in skeletal class III malocclusion. The sample consisted of 30 adult class III malocclusion patients who have received bilateral sagittal split mandibular osteotomy. Lateral cephalograms were taken before treatment, after presurgical orthodontic treatment and 3 months after orthognathic surgery. Skeletal and symphyseal measurements were compared and the relationships between them were analysed. The results were as follow: 1. The labial and lingual alveolar bone height in presurgical and postsurgical group were decreased than that of pretreatment group. 2. The vertical measurements of the craniofacial skeleton showed reverse correlationship with anteroposterior width of basal alveolar bone, but IMPA showed correlationship(p<0.01). 3. The craniofacial skeleton and the change of symphyseal measurements(symphyseal length, symphyseal width) showed no correlationship. 4. The labial alveolar bone height showed correlationship with lingual alveolar bone height(p<0.001), and negative correlationship with lingual alveolar crestal width(p<0.01). Labial and lingual alveolar crestal width has negative correlationship (p<0.05). Mandibular symphyseal length and width has positive correlationship(p<0.01). 5. IMPA, LISA showed negative correlationship with labiolingual alveolar bone height and lingual alveolar width and positive correlationship with labial alveolar base bone width.