INTERNATIONAL JOURNAL OF ORAL-MEDICAL SCIENCES

Vol. 6 No. 1      AUGUST - 2007

ISSN: 1347-9733      UBIC: 136-M

Abstract

The purposes of this study were to investigate the facial changes by two-jaw surgery for mandibular prognathism accompanying maxillary hypoplasia and skeletal open bite, and to design a regression model that predicts the soft tissue profile changes after two-jaw surgery. Fourteen cases diagnosed as mandibular prognathism accompanying maxillary hypoplasia and skeletal open bite at the Nihon University Hospital, School of Dentistry at Matsudo were studied. The surgical methods used were Le Fort type I osteotomy for the maxilla and sagittal split ramus osteotomy for the mandible. Angle measurements showed significant differences in SNA, ANB, FA, FD and MPA (p< 0.01), and significant difference in SNB (p<0.05). In horizontal distances, PTV-L1, PTV-Id, PTV-B, PTV-Pog and PTV-Me changed significantly (p<0.01). In vertical distances, a significant change in N -Me was observed (p<0.05). In horizontal distances, significant changes were observed in PTV-Li and PTV-Spog (p<0.01), and in PTV-St (p<0.05). In vertical distances, significant changes in PTV-St and PTV-Li were observed (p<0.05). No significant changes in cheek line were observed. For the horizontal lip and chin position, the multiple correlation coefficients R ranged from 0.89 to 0.95, and for the horizontal position of the cheek line, the multiple correlation coefficients R ranged from 0.65 to 0.84, indicating a high precision of the prediction equations obtained in this study. In conclusion, the result of this study indicates that the prediction equation for lips and chin has a high precision and can be applied to predict soft tissue profile in two -jaw surgery. Keywords: two-jaw surgery, soft tissue profile, prediction.

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