title: Cone beam computed tomography 3D reconstruction of the mandibular condyle.
abstract: OBJECTIVE
  To determine the ideal window level and width needed for cone beam computed three-dimensional (3D) reconstruction of the condyle.
  
  
  METHODS
  Linear dimensions were measured with a digital caliper to assess the anatomic truth for 50 dry human mandibular condyles. Condyles were scanned with the i-CAT cone beam computed tomography (CBCT) and 3D-models were reconstructed. Three linear three-dimensional measurements were made on each of the 50 condyles at 8 different Hounsfield unit (HU) windows. These measurements were compared with the anatomic truth. Volumetric measurements were also completed on all 50 condyles, at 23 different window levels, to define the volumetric distribution of bone mineral density (BMD) within the condyle.
  
  
  RESULTS
  Significant differences were found in two of the three linear measurement groups at and below the recommended viewing window for osseous structures. The most accurate measurements were made within the soft tissue range for HU window levels. Volumetric distribution measurements revealed that the condyles were mostly comprised of low-density bone, and that condyles exhibiting significant changes in linear measurements were shown to have higher percentages of low-density bone than those condyles with little change from the anatomic truth.
  
  
  CONCLUSIONS
  CBCT assessment of the mandibular condyle, using the 3D reconstruction, is most accurate when accomplished at density levels below that recommended for osseous examination. However, utilizing lower window levels which extend into the soft tissue range, may compromise one's capacity to view the bony topography.
authors.affiliation: Department of Orthodontics, Saint Louis University, St Louis, MO 63104, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Schlueter
authors.forename: Ki Beom
authors.initials: KB
authors.lastname: Kim
authors.forename: Donald
authors.initials: D
authors.lastname: Oliver
authors.forename: Gus
authors.initials: G
authors.lastname: Sortiropoulos
mesh_terms: D015519:Bone Density; D002508:Cephalometry / Q000379:methods; D017076:Computer-Aided Design; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008335:Mandibular Condyle / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D008953:Models, Anatomic; D011829:Radiation Dosage