A computerized tomographic study on the structure of the mandibular ramus

Kim, Pyoung Soo; Ahn, Yung; Jin, Woo Jeoung; Koh, Kwang Joon

Abstract

This study was conducted for the purpose of suggestion of the new technique of sagittal split ramus osteotomy pararell to the true sagittal plane. This pararellism is the important concept of the sagittal split ramus osteotomy to reduce the condylar sagging including mandibular hypomobility, temporomandibular disorder, occlusal relapse and other complications. We used 26 adult dry manibles(52 rami), and obtained the computed tomographs through the sagittal, horizontal and coronal sections. The results were obtained as follows. 1. On sagittal section, mean area of S1 was 8.63+/-2.10cm2, S2 was 8.93+/-1.94cm2, S3 was 9.49+/-2.15cm2, S6 was 10.72+/-2.22cm2. The wider area of sagittal section, the more lateral section, But, no significant differency between the areas of the sagittal sections(P>0.05). 2. On horizontal section, The distance between the inferior alveolar canal and the lateral cortical plate of the mandibular ramus were 6.73+/-1.24mm minum, 7.70+/-1.44mm maximum. 3. On coronal section, Outer mandibular angle were 4.84+/-2.37degrees right side, 4.93+/-2.12degrees left side. 4. The design of the ideal true sagittal split ramus osteotomy is that posterior border of osteotomy must be limited vertically, at the right posterior point of lingula mandibularis and anterior border of osteotomy must be extended to mandibular body, anteroinferiorly.