A Novel Method for Proximal Segment Management: Correct Condyle Head Repositioning and Better Proximal Segment Placement
Yong-chan Lee, DDS, Ph.D*, Hong-byum Sohn, DDS, Ph.D**
Min-soo Kwon, DDS, MSD*, Ki-young Kim, DDS, MSD*
*Department of Oral and Maxillofacial Surgery, Bestian Medical Center Seoul, Seoul, Korea
** Department of Orthodontics, Bestian Medical Center, Seoul, Korea
Precise preoperative plan and accurate surgery according to the surgical plan is mandatory for the best outcome of orthognathic surgery. Planning a precise surgical plan requires stereoscopic analysis of dentition, jaw bone and soft tissue, but the information from 2-D traditional analysis is limited in both quality and quantity. Recent advancement in 3-D software technology from either multislice computed tomography or cone-beam computed tomography allows computer-assisted surgery to be used safely in the operative environment. We developed a new method which is named Balanced Orthognathic Suegery(BOS) system which is a kind of Computer Assisted Surgery System. BOS describes all forms of 3-D surgical treatment objective (STO), 3-D printing technology for fabrication of surgical splints, condyle head positioning device, and prebended bone plates. The workflow of BOS consists of 4 phases as follows. 1) The planning and simulation phase, 2) The modeling phase, 3) The surgical phase, 4) The evaluation phase. The advantage of BOS is that BOS system supply useful tools such as computer generated intermediate and final surgical stents, condyle head positioning device, and prebended mini plates according to the RP models which enable surgeons to manage proximal segment properly. In order for BOS to be trustworthy, we must calculate accurately how much the bone segments move 3 dimensionally. Fortunately we can calculate the value of rotation and translational movements accurately, so the virtual reality surgical simulation fits into a real surgery correctly. By using BOS, achieving correct condyle head position, correcting maxillary yaw deformity, better placing proximal and distal segments, and restoring mandibular symmetry can be guaranteed. We compare the displacement value of the mandibular right and left condyles of 7 patients who was operated according to the BOS method (study group) with that of another 7 patients who was not operated according to the BOS method but to the traditional method(control group).
The linear displacement value of condylion was measured anterior-posterior, left-right, and superior-inferior direction and angular displacement value was measured by the rotation degree such as sagittal rotation, coronal rotation, and axial rotation. The mean left-right linear displacement value of study group was 0.40 , the mean of anterior-posterior linear displacement value was 0.42, the mean of superior-inferior displacement value was 0.50 contrast to that of control group was 0.78, 0.58, and 1.34 respectively.
The mean angular displacement value of study group : sagittal rotation, was 0.92 degree, coronal rotation was 1.49 degree, and axial rotation was 2.46 contrast to that of control group was 2.66 degree, 3.41 degree, and 4.36 degree respectively..
We have confidence that a novel method of digital convergence technology allows maxillofacial surgeons to manage proxiamal segments better than traditional method.
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