title: Comparison of cone-beam computed tomography cephalometric measurements using a midsagittal projection and conventional two-dimensional cephalometric measurements.
abstract: OBJECTIVE
  This study investigated whether it is possible to use a two-dimensional (2D) standard in three-dimensional (3D) analysis, by comparing the angles and lengths measured from a midsagittal projection in 3D cone-beam computed tomography (CBCT) with those measured by 2D lateral cephalometric radiography (LCR).
  
  
  METHODS
  Fifty patients who underwent both LCR and CBCT were selected as subjects. CBCT was reoriented in 3 different methods and the measuring-points were projected onto the midsagittal plane. Twelve angle values and 8 length values were measured on both LCR and CBCT and compared.
  
  
  RESULTS
  Repeated measures analysis of the variance revealed statistically significant differences in 7 angular and 5 linear measurements among LCR and 3 types of CBCT (p < 0.05). Of these 12 measurements, multiple comparisons showed that 6 measurements (ANB, AB to FH, IMPA, FMA, Co-Gn, Go-Me) were not significantly different in pairwise comparisons. LCR was significantly different from 3 types of CBCT in 3 angular (SN to FH, interincisal angle, FMIA) and 2 linear (S-Go, Co-ANS) measurements. The CBCT method was similar for all measurements, except for 1 linear measurement, i.e., S-N. However, the disparity between the mean values for all parameters was within the range of clinical measurement error.
  
  
  CONCLUSIONS
  3D-CBCT analysis, using midsagittal projection, is a useful method in which the 2D-LCR normative values can be used. Although the measurements changed with reorientation, these changes were not clinically significant.
authors.affiliation: Department of Orthodontics, Gachon University Gil Medical Center, Incheon, Korea.
authors.forename: Pil-Kyo
authors.initials: PK
authors.lastname: Jung
authors.affiliation: Department of Orthodontics, Gachon University Gil Medical Center, Incheon, Korea.
authors.forename: Gung-Chol
authors.initials: GC
authors.lastname: Lee
authors.affiliation: Department of Orthodontics, Gachon University Gil Medical Center, Incheon, Korea.
authors.forename: Cheol-Hyun
authors.initials: CH
authors.lastname: Moon
keywords: Cephalometrics; Cone-beam computed tomography (CBCT); Diagnosis and treatment planning; Reorientation