Three-dimensional vector analysis of mandibular structural asymmetry.
OBJECTIVE
The three-dimensional (3D) asymmetric structure of the mandible makes it necessary to analyze both its size and angle. Currently the developing 3D analysis techniques are not able to perform the simultaneous linear and angular measurements. Our aim was to evaluate mandibular asymmetry using a vector-based system by constructing 3D vectors for the mandibular functional units.


METHODS
We analyzed the 3D computed tomography images of normal control (N = 27) and asymmetric mandibles (N = 40). We created 3D vectors for the condylar, coronoid, body, gonial, and symphyseal functional units and compared the corresponding pairs of 3D vectors by calculating vector operations.


RESULTS
The vector difference and other vector components represented the individual 3D architectural pattern and severity of the asymmetric mandible. The body unit contributed most to mandibular asymmetry followed by the condylar unit.


CONCLUSIONS
The results indicate that 3D vector analysis can improve our understanding of the 3D architecture of asymmetric mandibles. This type of 3D vector analysis can be a useful tool for the comprehensive evaluation of its asymmetric mandibular structure.
Department of Oral and Maxillofacial Surgery, College of Dentistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Republic of Korea.
Kyung-Ran
KR
Park
Hyung-Seog
HS
Park
Zhengguo
Z
Piao
Moon-Key
MK
Kim
Hyung-Seog
HS
Yu
Jin Keun
JK
Seo
Sang-Hwy
SH
Lee
D000328:Adult; D000465:Algorithms; D059925:Anatomic Landmarks / Q000000981:diagnostic imaging / Q000473:pathology; D002508:Cephalometry / Q000379:methods*; D002680:Chin / Q000000981:diagnostic imaging / Q000473:pathology; D003198:Computer Simulation; D005146:Facial Asymmetry / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008334:Mandible / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D008335:Mandibular Condyle / Q000000981:diagnostic imaging / Q000473:pathology; D008336:Mandibular Diseases / Q000000981:diagnostic imaging / Q000473:pathology*; D008953:Models, Anatomic; D014057:Tomography, X-Ray Computed / Q000379:methods; D055815:Young Adult