Development of a simulation system in mandibular orthognathic surgery based on integrated three-dimensional data.
OBJECTIVE
Surgical simulation should reflect the 3D movement of dentition and the resultant movement of the osteotomized segments, which can influence surgical outcome. The present study was aimed at developing a new simulation system that enables virtual osteotomy of a given surgical situation and evaluation of the bony interference between the osteotomized segments of the mandible.


METHODS
The data of 3D computer tomography (CT) for maxillomandibular dental casts were integrated into the standard coordinates of a 3D cephalogram. To evaluate the accuracy of the system, measurement errors of the 3D CT virtual model from a dry skull were compared with the computer simulation system and a contact-type 3D digitizer. To examine the clinical accessibility, 15 mandibular prognathism patients with mild to severe asymmetry were evaluated with the simulation program.


RESULTS
The average error of measurement in all directions was 1.31 mm. It was possible to simulate various osteotomy procedures by conversion of the 3D coordinates of the dental cast and CT data into the standard coordinate system of a 3D cephalogram. Using this simulation system, it was possible to prevent condylar torque or segment malpositioning by removing the bony interference visualized by a 3D virtual model.


CONCLUSIONS
A new system, which enables the precise visualization of osteotomized segments and calculation of bony interference, was proposed in the present study. This new system provides an acceptable precision of treatment planning of orthognathic surgery, especially for facial asymmetry.
Mori
Yoshihide
Y
Department of Oral and Maxillofacial Surgery, Graduate School of Dentistry, Kyushu University, Higashi-ku, Fukuoka, Japan. y-mori@dent.kyushu-u.ac.jp
Shimizu
Hidetaka
H
Minami
Katsuhiro
K
Kwon
Tae-Geon
TG
Mano
Takamitsu
T
D001860:Bone Plates; D001864:Bone Wires; D002508:Cephalometry / Q000379:methods; D003198:Computer Simulation; D005146:Facial Asymmetry / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D005544:Forecasting; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging / Q000601:surgery*; D008335:Mandibular Condyle / Q000000981:diagnostic imaging / Q000473:pathology; D003765:Models, Dental; D056948:Orthognathic Surgical Procedures / Q000379:methods*; D059229:Osteotomy, Sagittal Split Ramus / Q000379:methods*; D010347:Patient Care Planning; D011378:Prognathism / Q000601:surgery; D015203:Reproducibility of Results; D012399:Rotation; D014057:Tomography, X-Ray Computed / Q000379:methods; D019415:Torque; D014584:User-Computer Interface; D055815:Young Adult