Introduction: Although precise prediction of results before DO is of paramount importance, performing 3D simulations for all DO patients is not practical. Therefore, formulation of general guidelines based on the factors affecting three dimensional results of distraction treatment is recommended.
Methods: This study was performed on a three dimensional model of a desiccated mandible, based on a finite element method. Oblique, vertical and horizontal cuts were made on the right side of the mandible. The distractor pins were opened first for 15 mm and then for 30 mm. Amount and direction of movement of proximal and distal segments and the displacement of pogonion were evaluated in all three planes of space.
Results: The movements of proximal and distal segments were shown in multiple finite element diagrams. In the distal segment, maximum displacement in the pogonion occurred in the vertical cut. In the proximal segment, maximum displacement occurred in the coronoid process in horizontal and oblique cuts in a superior direction. The condylar process rotated in a clockwise direction when the vertical cut was used and the coronoid process moved inferiorly.
Conclusion: In order to make the gonial angle more prominent, we should use a vertical surgical cut. Conversely, a horizontal cut is used to lengthen the ramus. In vertical and oblique cuts, the distal segment and pogonion are displaced superiorly, whereas in horizontal cuts, this landmark is displaced inferiorly. Therefore, vertical and oblique cuts can be used in patients with long anterior facial heights, and considering all other conditions as being equal, horizontal cuts are preferred to be used in short-faced patients. If mandibular body length is very short, it is better not to use a horizontal cut because this cut does not result in lengthening of the distal segment in the antero-posterior dimension.
Keywords: Distraction Osteogenesis, Mandible, Asymmetry.