Objective: To evaluate the surgical accuracy of the maxillary repositioning in three-dimensional virtual model surgery(3D-VMS) and intermediate wafer(IW) fabrication according to surgical movement type(SMT) of the maxilla in two-jaw surgery(TJOS).
Introduction: Prior to orthognathic surgery, the surgical treatment objective is essential for oral and maxillofacial surgeon and orthodontist. Conventional manual model surgery(MMS) has been used for a long time, which requires many laboratory steps. 3D-VMS was based on 3D scanning and STO was performed in computer-based simulation. A 3D virtual intermediate surgical wafer was fabricated by using a stereolithographic technique.
Materials and methods: The samples consisted of 11 Korean adults with skeletal discrepancies treated with two-jaw orthognathic surgery from July to August in 2008 by one surgeon. The preoperative and postoperative 1-day lateral cephalograms were analyzed for maxillary repositioning. The horizontal reference plane(SN-7) and vertical reference plane which was perpendicular to SN-7 plane at the sella were used. The measurements in the lateral cephalograms were compared with STO and OP record. The data with a discrepancy of 1mm or more between predicted and actual landmark location were regarded as incorrect. Subgroups were as followed; Group 1: maxillary advancement(MA), Group 2: maxillary set-back(MS), Group 3: maxillary upward(MI), Group 4: maxillary downward movement(ME).
Result: The accuracies were 100% on the MA, MS, ME and 80% on the MI. This result showed us that a 3D-VMS method was accurate and effective.
Discussion: Although 3D-VMS costs more than MMS, it is less time-consuming and can reduce the amount of laboratory works and errors.