A STUDY ON THE CHANGE THE UPPER LIP AFTER SAGITTAL SPLIT RAMUS OSTEOTOMY

ABSTRACT

osteotomy have been commonly performed for the correction of mandibular prognathism, occurred to abundant oriental people. Many authors have studied the soft tissue change after orthognathic surgery, especially between mandibular hard tissues and soft tissue of lower lip, but the study of upper lip change is comparatively little. Therefore, we studied the 12 patients, operated only sagittal split ramus osteotomy without genioplasty or maxillary osteotomy in department of oral and maxillofacial surgery, Hanyang university hospital from 1996.1. 1. to 1998. 7. 20. Preoperative and postoperative cephalometric view was measured to know the change of upper lip position and shape after mandibular setback. The result were obtained as follows. 1. The ratio of upper lip change amount to lower incisor horizontal movement was 15.1%. 2. The ratio of lower facial profile between Sn-Stm and Stm-Mes was changed from 1 2.352 to 1 2.069 after operation. 3. Post-operative upper lip was flattened 72.4% compared with pre-opreative one. 4. The vermilion zone of the upper lip increased 56% horizontally, 5.8% vertically after operation. 5. The vermilion zone ratio of the lower lip to the upper lip was change from 1 1.253 to 1 1.348. 6. The distance between esthetic line and Ls was changed from -3.958mm to -1.15mm.