The validity of using surface meshes for evaluation of three-dimensional maxillary and mandibular surgical changes.
The three-dimensional (3D) changes in hard tissue position following orthognathic surgery have been reported using 3D cephalometry, changes in volume, principal component analysis, and changes based on the surface model of the hard tissue. The aim of this study was to determine the validity of using surface models as a method of assessing positional changes of the maxilla and mandible. The actual unidirectional movement of the maxilla (advancement or downgraft) and the mandible (advancement), together with bidirectional movement of the maxilla (simultaneous advancement and downgraft) were simulated on a plastic skull. Following cone beam computed tomography scanning of each surgical simulation, the actual surgical movement was compared to the analysis based on surface model movement using the mean absolute distance of all points, the 90th percentile, and the root mean square (RMS) distance. All three methods of assessment of analysis consistently underestimated the actual amount of surgical movement. The movement was approximately one-third to one-half of the actual surgical movement. The use of surface meshes and point-to-point measurements grossly underestimates the 3D changes in the maxilla and mandible in simulated surgical procedures. Currently there are limitations in fully describing the true positional changes of the maxilla or the mandible in three dimensions.
Paediatric Dentistry and Orthodontics, Faculty of Dentistry, The University of Hong Kong, Hong Kong.
N
N
Jabar
Paediatric Dentistry and Orthodontics, Faculty of Dentistry, The University of Hong Kong, Hong Kong.
W
W
Robinson
Oral Diagnosis and Polyclinics, Faculty of Dentistry, The University of Hong Kong, Hong Kong.
T K
TK
Goto
Paediatric Dentistry and Orthodontics, Faculty of Dentistry, The University of Hong Kong, Hong Kong. Electronic address: bkhambay@hku.hk.
B S
BS
Khambay
D054893:Cone-Beam Computed Tomography; D004867:Equipment Design; D006801:Humans; D021621:Imaging, Three-Dimensional; D008334:Mandible / Q000000981:diagnostic imaging / Q000601:surgery*; D008437:Maxilla / Q000000981:diagnostic imaging / Q000601:surgery*; D008953:Models, Anatomic; D056948:Orthognathic Surgical Procedures; D019340:Osteotomy, Le Fort; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results
3D; CBCT; surface mesh; surgical change; three-dimensional