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[Three-dimensional finite element analysis for external midface distraction after different osteotomy in patients with cleft lip and palate].

OBJECTIVE
To study three-dimensional finite element analysis for external midface distraction after different osteotomy in patients with cleft lip and palate (CLP).


METHODS
Three-dimensional FEM models of Le Fort I, II and III osteotomy in CLP patients were established. External midface distraction were simulated. An anteriorly and inferiorly directed 900 g force was applied to bilateral maxillary arch in directions 30 degrees to the occlusal plane. Biomechanical changes for the maxillary complex were investigated by means of finite element analysis.


RESULTS
Maxillary complex was advanced after different osteotomy. Constriction of alveolar crest and palate occurred in Le Fort I osteotomy, but not in Le Fort II and III osteotomy. Clockwise rotation occurred in Le Fort I osteotomy complex. Counterclockwise rotation occurred in Le Fort II and III osteotomy complex.


CONCLUSIONS
Three-dimensional finite element research on external midface distraction could provide reference for the preoperative design.