Prediction of soft tissue profiles in orthodontic surgery with the Dentofacial Planner

Since the early 1990s, there have been continuous improvements in the software available for planning orthognathic surgery. This study investigates the precision of profile prediction by version 1.51 of the Dentofacial Planner (DFP). Orthognathic operations in 40 patients with different types of dysgnathia were evaluated. The preoperative and postoperative lateral cephalograms were analyzed in the DFP. The computer profiles were simulated on the basis of the skeletal alterations of the jaws observed postoperatively. The predicted soft tissue profiles were compared with the postoperative profile lines and evaluated statistically. The quality of the soft tissue prediction varied from one profile region to another. Significant differences were shown in various operation categories. Appreciable prediction errors were observed in the lip region. In particular, the upper lip revealed inadequate protrusion in bimaxillary operations. The smallest number of significant errors was found in single-jaw operations on the mandible. Significant features were not shown in the chin prediction profile, especially caudal to the superior labiomental furrow. The DFP version tested in the investigation shows some improvements in the convenience of the application compared to the previous versions. The profile prognosis is satisfactory, even in complicated bimaxillary operations. Results continue to be unsatisfactory in the lip profile prognosis. Further development of the software is necessary.