Patient-Specific Printed Plates Improve Surgical Accuracy In Vitro

Abstract

It remains unclear to what extent patient-specific printed plates can improve surgical outcomes in orthognathic procedures. This study aimed to quantify the surgical accuracy of patient-specific printed plates invitro and to compare the results with patients' actual surgical outcomes. This invitro study enrolled 20 postoperative orthognathic surgical patients, all treated with inferior maxillary repositioning. The preoperative midfaces were re-created in a 3-dimensionally printed model. The osteotomy and screw holes were placed at prespecified positions using a 3-dimensional guide. The dental segment was repositioned by means of the patient-specific plates. The primary outcome was the mean reposition at 3 dental reference points. The primary predictor variable was the obtained surgical reposition invitro compared with the virtual surgical plan. Confounding variables were gender, age, occlusion, and bimaxillary surgery. The secondary outcome was surgical accuracy, and the secondary predictor was the invitro outcomes versus the patients' surgical outcomes. Surgical accuracy was defined as the difference between the obtained reposition and the virtual surgical plan on a continuous scale. The differences were recorded in 3 dimensions according to the positive valueof the 3 axes: right, anterior, and posterior. The results were analyzed using mixed-model regression and 1-sample t tests. In the 20 patients (age, 18 to 64years; 40% of patients were women), the mean planned reposition was 2.9mm anterior and 1.8mm inferior. In all models, the osteotomy edge was rounded off to position the plate in the predetermined position. Overall, the maxilla was positioned 0.5mm anterior and 0.3mm inferior to the planned position using patient-specific plates. The patient-specific plates positioned the maxilla in close approximation to the planned position without surgically relevant differences. The osteotomy edge must be carefully inspected for interference with the patient-specific plates to avoid displacement of the planned maxillary repositioning.