THE VALIDITY OF THE PREDICTION OF SOFT-TISSUE PROFILE CHANGES AFTER LEFORT-I OSTEOTOMY USING THE DENTOFACIAL PLANNER (COMPUTER SOFTWARE)

The purpose of this study was to examine the validity of the prediction of soft tissue changes after LeFort I osteotomy with the DentoFacial Planner (DFP) (computer software). The preoperative and postoperative lateral cephalograms of 21 white adult orthodontic patients (10 males and 11 females) who underwent only LeFort I osteotomy as part of their overall treatment were digitized. A coordinate system of X and Y axes were used to assess the amount and direction of movement of the maxilla. The SN + 7-degrees was the X axis, and a perpendicular to this plane from nasion was the Y axis. The sample was divided into two groups depending on the amount of forward movement of the maxilla. More than 2 mm of anterior placement of the maxilla comprised the advancement group (13 patients) and less than 2 mm comprised the impaction group (8 patients). The selection criteria for the sample were (1) before and after cephalograms taken with lips in repose and in centric occlusion; (2) all preoperative records taken almost immediately before surgery; (3) postoperative records taken at least 6 months after surgery and checked by regional superimposition of the preoperative and postoperative lateral cephalograms onto the maxilla and the mandible. No tooth movement occurred between the time the records were taken. The following soft tissue landmarks were examined: pronasale, subnasale, stomion superior, middle upper lip, stomion inferior, middle lower lip, labrale inferior, labiomental fold, and pogonion. The results indicate that for some of these landmarks the amount and direction of soft tissue changes differed between the DFP prediction and the actual surgical changes by LeFort I osteotomy. Differences between actual and predicted changes may be partially attributed to the variability of surgical procedures of previous studies that provided the data for the DFP computer software.