Morphologic study of mandibular outer cortex osteotomy.

BACKGROUND

The purpose of this study was to illustrate the morphologic changes of the mandible after outer cortex osteotomy.

METHODS

Ten patients had undergone mandibular outer cortex osteotomy. By using the true-up and dissection techniques based on three-dimensional spiral computed tomography, variables of effect and bone regeneration were evaluated 6 months postoperatively.

RESULTS

Concavity could be seen in the area from which the mandibular outer cortex had been removed 6 months postoperatively, especially at the external oblique line region. The average cup depth was 3.64 +/- 1.67 mm postoperatively. Diminution of bone volume was 1.7 +/- 0.5 percent for the entire mandible and 55 +/- 9 percent for the local area 6 months postoperatively. Bone regeneration could be seen in the area from which the mandibular outer cortex had been removed. Compared with immediately postoperatively, the ratio of neoformative bone was 84.6 +/- 7.3 percent 6 months postoperatively. The main region of bone regeneration was the mandibular angle.

CONCLUSIONS

Mandibular outer cortex osteotomy is an effective technique for reducing the width of the lower face. Masseter muscular movement should be restricted postoperatively to prevent hyperostosis at the angle area.