Three-dimensional morphometric analysis of mandibule in coronal plane after bimaxillary rotational surgery / 대한악안면성형재건외과학회지

BACKGROUND: The aim of this report is to present a new reference for aesthetic mandible surgery using three-dimensional cone-beam computed tomography-based treatment planning for orthognathic surgery which can be implemented in surgical planning and perioperative procedure. METHODS: To make an objective standard for evaluating aesthetic mandibular outline, we make an aesthetic scoring criteria with consideration of asymmetry, broad mandibular border line, and prominent mandibular angle. Two maxillofacial surgeons and two orthodontists rated their aesthetical evaluation from 1 to 5. Experimental group consisting of 47 female and 38 male patients who had rotational orthognathic two-jaw surgery from 2010 to 2011 were chosen according to aesthetic scoring done by two maxillofacial surgeons and two orthodontists. A high aesthetic score (≥16) means the facial contour is symmetric, with no broad and narrow aesthetic mandible frontal profiles. Control A group consisted of ten female and ten male patients who had no orthognathic surgery experience and low aesthetic score (≤10). Control B group consisted of ten female and ten male patients who had no orthognathic surgery experience and had anaesthetic mandibular frontal profile and a high aesthetic score (≥16). The three-dimensional image of the patient was taken from dental cone-beam CT (DCT) scanning (experimental group and control A group: 6 months DCT after surgery, control B group: 1st visit DCT). Each DCT was reformatted to reorient the 3D image using 3D analyzing program (OnDemand3D, cybermed Inc, CA, USA). After selection of 12 landmarks and the construction of reoriented horizontal, vertical, and coronal reference lines, 15 measurements were taken in 3D analysis of frontal mandibular morphology. Afterwards, horizontal and vertical linear measurements and angular measurements, linear ratio were obtained. RESULTS: Mean Go’(Rt)-Me’-Go’(Lt) angular measurement was 100.74 ± 2.14 in female patients and 105.37 ± 3.62 in male patients. These showed significant difference with control A group in both genders. Ratio of Go’(Rt),Go’(Lt)-Me’ length to some linear measurements (ratio of Me’-Cd’RtCd’Lt to Me’-Go’(Rt)Go’(Lt), ratio of Me’-Go’ to Me’-Go’(Rt)Go’(Lt), ratio of Go’(Rt)-Go’(Lt) to Me’-Go’(Rt)Go’(Lt)) showed significant difference with control A group in both genders. CONCLUSION: This study was intended to find some standard measurement of mandible frontal view in 3D analysis of aesthetic patient. So, these potential measurement value may be helpful for orthognathic treatment planning to have more aesthetic and perspective outcomes.

The Angles of the Mandible in Korean - Three Dimensional Reconstruction Study / 체질인류학회지

The aim of this study was to analyze the difference of the measurements of mandible between young male and female using three dimensional reconstruction images derived from the facial bone CT images. Type classification of mandible was performed based on the angle of base of mandible and the angle of mandibular margin observed from the anterior view and the correlation among the measurement items was analyzed. One hundred-ninety five young adults facial CT were collected from the Konkuk University medical center (98 females, 97 males; mean age 25.9 years, range 18~38 years). Three dimensional images of the face were reconstructed using software from CT images of whole specimens. The angle of the base of the mandible, the angle of the mandibular margin, total length of mandibualr margin, and the height of mandibular symphysis were measured. All measurement items were larger and longer in male than female (P<0.05). Three types were classified according to the mandibular angle. In female, the subjects were evenly distributed among groups, but group I which had large mandibular angle was most common in male. The smaller the height of mandibular symphysis, the larger the angle of base of mandible or the angle of mandibular margin (P<0.05).