Evaluation of accuracy of maxillary repositioning surgery using an observer-independent method

Abstract

ObjectiveTo evaluate the accuracy of maxillary repositioning in two-jaw surgery using computer-aided surgical simulation (CASS) and computer-aided design/manufacturing (CAD/CAM) splints by using a highly accurate observer-independent method. MethodsA retrospective evaluation was conducted of 30 consecutive adults who underwent Le Fort I osteotomy by a single surgeon. Surgical planning and fabrication of occlusal splints were performed using custom-developed CASS software. Preoperative images with landmarks were superimposed on postoperative images to evaluate discrepancies between the planned and actual position of the maxilla following surgery. Translational and rotational differences were expressed as the root mean square deviation (RMSD). The number of cases that exceeded the clinically acceptable limits (2 mm for the translational difference at the centroid, 4° for the rotational difference, and 1 mm for the mediolateral difference at the dental midline) were also evaluated. ResultsPostoperative anteroposterior translation and pitch values were significantly different to and negatively correlated with the planned values, respectively. The largest translational RMSDs at the centroid and the dental midline were 1.04 mm and 1.03 mm, respectively, in the anteroposterior direction. The largest rotational RMSD was 1.86° in pitch. The percentage of discrepancies exceeding the clinically acceptable limit was 3.3% for the centroid, 3.3% for rotation, 20.0% for the midline, and 26.7% for any one criterion. ConclusionWhile maxillary repositioning using CASS and CAD/CAM splints was accurate on a population level, there remains potential for clinically significant errors to occur on an individual level, particularly in controlling the dental midline position and occlusal plane angle.