OBJECTIVETo discuss the trend of displacement on the side of nondistraction when distraction osteogenesis with unilateral incomplete osteotomy of canine mandible.

METHODSThe method of finite element analysis was used to simulate distraction osteogenesis with unilateral incomplete osteotomy and the displacement of six marked point such as the temporomandibular joint and the angle of mandible and coracoid process and teeth were observed on nondistractional side when the transport disc was distracted with a distance and without a distance.

RESULTSWhen the transport disc was distracted without a distance, the Von Mises stress was 0 in the six marked point of nondisractional side and their displacement in 3 dimensions (X, Y, Z axis) was 0. When the transport disc was distracted with 1 mm width, all marked point had some displacement.

CONCLUSIONWhen distracted and observed from the side of distraction, the mandible at the side of nondistraction has the trend of contrarotation round the center of the transverse ridge mid-point of condyle process on the plane of sagittal, whereas it has the trend of parallel movement approximately in the direction of opposite side on the plane of coronary.