OBJECTIVETo investigate the changes of mandibular vitodynamics in powerful bite working condition and impact working condition after mandibular angle osteotomy through 3-dimensional finit element analysis.

METHODSA patient of prominent mandibualr angle without malocclusion was selected and underwent 3-dimensional CT before and after operation. The DICOM data of 3-dimensional CT were read by Mimics software and 3-dimensional images were reconstructed. Then the 3-dimensional images were changed into IGES format and imported into ANSYS10.0. The boundary constrained condition and pre-processing condition was setting in ANSYS10.0 software. The 3-dimensional finite element models were generated in ANSYS10.0. Solution process was running and most powerful bite working condition and impact working condition were simulated and calculated.

RESULTSIn static stress analysis, the stress peak and stress maximal value point of mandible were basically at equal pace in preoperative and postoperative models. In transience dynamic stress analysis, although stress discrepancies were found in part time point and some region of mandible between preoperative model and postoperative model, the direction and topography of main stress were basically at equal pace. Main stress distributed beside external oblique line and concentrates at the neck of condyle. There was no significant difference of stress conduction and distribution between preoperative and postoperative models.

CONCLUSIONSCompared with preoperative model, postoperative model has different transduction phases of stress, but has almost the same tolerance extents of main stress.