1989 Volume 38 Issue 4 Pages 1023-1036
Moiré topography was employed to evaluate pre- and post-facial contour changes in 42 cases of mandibular prognathism treated by sagittal split osteotomy. The relation between bony changes and related soft-tissue change induced by surgery was also studied.
In the mandibular prognathism without asymmetry group:
1) Marked retraction was noticed in the chin region ; i. e. aproximately 1: 1 correlation with underlying bony change was observed, and this decreased progressively upward and backward.
2) The upper lip was slightly reduced by the osteotomy. No direct effect, however, was observed in the buccal region.
3) Soft tissue chages in the lower third of the face were strongly correlated to the movement of the underlying skeletal structure. The degree of mandibular set-back and mandibular counterclockwise rotation correlated highly with soft-tissue changes around the chin.
In the mandibular prognathism with asymmetry group:
1) No definite changes were noticed in the lower soft-tissue around the chin area.
2) In addition to backward movement and counterclockwise rotation, lateral rotation of the mandible also played a role in post-operative facial soft-tissue changes. Precise pre-operative prediction proved difficult.
More detailed three dimentional facial evaluation using Moiré topography may be obtained as compaired with the previous reports by using sagittal plane analysis of the lateral cephalogram.
