title: Evaluation of canting correction of the maxillary transverse occlusal plane and change of the lip canting in Class III two-jaw orthognathic surgery.
abstract: OBJECTIVE
  To compare the effect of canting correction in anterior maxillary transverse occlusal planes (AMTOP) and posterior maxillary transverse occlusal planes (PMTOP) on the change of lip canting (LC) in two-jaw surgery (TJS) cases.
  
  
  METHODS
  The samples consisted of eight young adult patients (three males and five females, mean age  =  24.1 ± 4.5 years) who had skeletal Class III malocclusion (CIII), facial asymmetry (FA), and LC and who underwent TJS. Two-dimensional lateral and posteroanterior cephalograms and three-dimensional facial scanning taken 1 week before (T1) and 6 months after TJS (T2) were combined using the Morpheus 3D program. Six linear and angular variables were measured and statistically analyzed.
  
  
  RESULTS
  When comparing the values of the linear and angular variables at the T1 and T2 stages there was significant canting correction of AMTOP (1.7 mm vs -0.3 mm; 3.0° vs 0.1°), PMTOP (3.5 mm vs 0.1 mm, 3.3° vs -0.1°), and LC (3.0 mm vs 0.7 mm, 4.7° vs 2.1°) (all P < .05). Although the angular change ratios (ΔLC/ΔAMTOP and ΔLC/ΔPMTOP) did not exhibit a significant difference (0.99 vs 0.83), the linear change ratio of ΔLC/ΔAMTOP was significantly higher than that of ΔLC/ΔPMTOP (1.67 vs 0.74, P < .05). The angular change of ΔLC showed a significant correlation with ΔAMTOP (r(2)  =  0.64; P < .05). However, the linear change of ΔLC was significantly correlated with both the angular and linear changes of ΔAMTOP (r(2)  =  0.62 and 0.66; both P < .05). Therefore, the amount of LC change was more related to the canting correction of AMTOP than to that of PMTOP.
  
  
  CONCLUSIONS
  In TJS cases with CIII, FA, and LC, the amount of canting correction of the AMTOP should be considered to predict the actual LC change.
authors.affiliation: School of Dentistry, Seoul National University, South Korea.
authors.forename: Seung-Jae
authors.initials: SJ
authors.lastname: Kim
authors.forename: Jin-Young
authors.initials: JY
authors.lastname: Choi
authors.forename: Seung-Hak
authors.initials: SH
authors.lastname: Baek
mesh_terms: D000328:Adult; D002508:Cephalometry / Q000379:methods*; D003766:Dental Occlusion; D005146:Facial Asymmetry / Q000601:surgery*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008046:Lip / Q000002:abnormalities*; D008297:Male; D008313:Malocclusion, Angle Class III / Q000601:surgery*; D009971:Orthodontics, Corrective / Q000379:methods; D056948:Orthognathic Surgical Procedures; D019340:Osteotomy, Le Fort / Q000379:methods; D059229:Osteotomy, Sagittal Split Ramus / Q000379:methods