Indications and limitations of CAD/CAM splints in Le Fort I osteotomy

The surgical outcome of planned Le Fort I osteotomy (LFI) is important for successful orthognathic surgery. The aim of this study was to evaluate the accuracy of LFI using a CAD/CAM intermediate splint by performing a three-dimensional (3D) comparison of the planned and postoperative maxillary positions. This retrospective study evaluated 31 patients who underwent LFI with a CAD/CAM intermediate splint. The patients were classified into three skeletal malocclusion types: Class III, Class II, and facial asymmetry. Five maxillary reference points and two axes were measured using computed tomography obtained pre-surgery and at 4 days post-surgery and on the preoperative virtual operation 3D images. The 'movement by simulation' and 'deviation from simulation' of the maxilla were analysed by surface superimposition of the virtual LFI osteotomy segments. The deviation from simulation of Class II in the anteroposterior direction, ranging from 1.11 ± 1.05 mm (at PNS) to 3.24 ± 1.09 mm (at U1) (mean ± standard deviation values for the reference points), was significantly more forwards than that of Class III (P < 0.001). A detailed 3D study of the accuracy of LFI using CAD/CAM splints revealed high accuracy and good indication for Class III, but low accuracy, with deviation that exceeded the clinically acceptable range, in Class II and facial asymmetry.