title: A new 3D method for measuring cranio-facial relationships with cone beam computed tomography (CBCT).
abstract: OBJECTIVE
  CBCT systems, with their high precision 3D reconstructions, 1:1 images and accuracy in locating cephalometric landmarks, allows us to evaluate measurements from craniofacial structures, so enabling us to replace the anthropometric methods or bidimensional methods used until now. The aims are to analyse cranio-facial relationships in a sample of patients who had previously undergone a CBCT and create a new 3D cephalometric method for assessing and measuring patients.
  
  
  METHODS
  90 patients who had a CBCT (i-Cat®) as a diagnostic register were selected. 12 cephalometric landmarks on the three spatial planes (X,Y,Z) were defined and 21 linear measurements were established. Using these measurements, 7 triangles were described and analysed. With the sides of the triangles: (CdR-Me-CdL); (FzR-Me-FzL); (GoR-N-GoL); and the Gl-Me distance, the ratios between them were analysed. In addition, 4 triangles in the mandible were measured (body: GoR-DB-Me and GoL-DB-Me and ramus: KrR-CdR-GoR and KrL-CdL-GoL).
  
  
  RESULTS
  When analyzing the sides of the CdR-Me-CdL triangle, it was found that the 69.33% of the patients could be considered symmetric. Regarding the ratios between the sides of the following triangles: CdR-Me-CdL, FzR-Me-FzL, GoR-N-GoL and the Gl-Me distance, it was found that almost all ratios were close to 1:1 except between the CdR-CdL side with respect the rest of the sides. With regard to the ratios of the 4 triangles of the mandible, it was found that the most symmetrical relationships were those corresponding to the sides of the body of the mandible and the most asymmetrical ones were those corresponding to the base of such triangles.
  
  
  CONCLUSIONS
  A new method for assessing cranio-facial relationships using CBCT has been established. It could be used for diverse purposes including diagnosis and treatment planning.
authors.affiliation: Department of Orthodontics, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain. natalia.zamora@uv.es
authors.forename: Natalia
authors.initials: N
authors.lastname: Zamora
authors.forename: Rosa
authors.initials: R
authors.lastname: Cibrián
authors.forename: Jose-Luis
authors.initials: JL
authors.lastname: Gandia
authors.forename: Vanessa
authors.initials: V
authors.lastname: Paredes
mesh_terms: D000293:Adolescent; D000328:Adult; D002508:Cephalometry / Q000379:methods*; D002648:Child; D054893:Cone-Beam Computed Tomography; D005147:Facial Bones / Q000033:anatomy & histology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008875:Middle Aged; D012886:Skull / Q000033:anatomy & histology*; D055815:Young Adult