Pitfalls in orthognathic model surgery. The significance of using different reference lines and points during model surgery and operation.

The planning of orthognathic surgery usually involves a simulation of jaw movements in a semi-adjustable articulator. The use of vertical and horizontal references during model surgery and operation have previously been described in great detail. The purpose of the present study was to quantify the errors resulting from using different reference lines and points in model surgery and operation. The results indicate that clinically significant differences between the planned and surgical jaw movement can result from the erroneous transfer of reference lines and points between model surgery and operation. Solutions to some of the problems discussed are suggested.