title: Digital method for quantification of circumferential periodontal bone level using cone beam CT.
abstract: OBJECTIVE
  The objective of this study is to develop a new approach for radiographically measuring circumferential periodontal bone level using cone beam CT (CBCT) data. Accuracy and precision were assessed using direct probe measurements on a human skull as a reference.
  
  
  METHODS
  Digital quantification of circumferential periodontal bone levels was conducted considering bone level measurements, infrabony crater, and furcation detection. For this purpose, a human bony cadaver skull with a restoration free dentition was used, showing periodontal bony defects of teeth 15-17,25-27,35-37,45-47 (FDI classification). Image datasets were acquired using a Promax 3D CBCT device (Planmeca Oy, Helsinki, Finland) at 80 kV and 8 mA, 160 μm voxel size. Circumferential radiographic measurements between cemento-enamel junction and the alveolar crest for the mesial, central, and distal bone levels on the oral and vestibular sides of the examined teeth were carried out based on a prototype of specifically developed software. The measurements were performed by an expert panel of three independent, calibrated, and blinded observers. Manual probe measurements of the periodontal bone loss served as reference standard.
  
  
  RESULTS
  The adopted software allowed the quantification of periodontal bone loss at all examined teeth. Overall deviation between radiographic and manual measurements of the observers ranged between 0.36 and 0.69 mm; hereby, 83 % of all results were <0.5 mm. Comparing overall accuracy between the ten turns of radiological measurements, accuracy for all observers ranged from 0.29 to 0.46 mm. The present study design showed a 100 % detection of furcation involvement for radiographic evaluation.
  
  
  CONCLUSIONS
  The adoption of a special measurement procedure in terms of a 3D coordinate system, which is placed through and perpendicular to the long axis of the tooth, allows consistent measurement positions of the mesial, central, and distal bone levels both for the oral and vestibular sides of the alveolar crest. In this way, reliable and reproducible quantification of circumferential periodontal bone loss using CBCT data with standardized resolution of 160 μm can be performed in all three dimensions.
  
  
  CONCLUSIONS
  This new approach of radiographically assessing circumferential periodontal bone level using CBCT data shows a first promising attempt of accurate detection of periodontal bony defects. Yet, possible negative impact of further clinical parameters in terms of artifact occurrence will have to be furthermore carefully investigated.
authors.affiliation: Oral Imaging Center, Faculty of Medicine, Katholieke Universiteit Leuven, Kapucijnenvoer 7, 3000 Leuven, Belgium. jonathan.fleiner@student.kuleuven.be
authors.forename: Jonathan
authors.initials: J
authors.lastname: Fleiner
authors.forename: Christian
authors.initials: C
authors.lastname: Hannig
authors.forename: Dirk
authors.initials: D
authors.lastname: Schulze
authors.forename: Andres
authors.initials: A
authors.lastname: Stricker
authors.forename: Reinhilde
authors.initials: R
authors.lastname: Jacobs
mesh_terms: D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging*; D000539:Alveolar Process / Q000000981:diagnostic imaging*; D059925:Anatomic Landmarks / Q000000981:diagnostic imaging; D002102:Cadaver; D002508:Cephalometry / Q000706:statistics & numerical data; D054893:Cone-Beam Computed Tomography / Q000706:statistics & numerical data*; D017823:Furcation Defects / Q000000981:diagnostic imaging*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000706:statistics & numerical data*; D021621:Imaging, Three-Dimensional / Q000706:statistics & numerical data; D015588:Observer Variation; D010517:Periodontics / Q000295:instrumentation; D012984:Software / Q000706:statistics & numerical data; D019237:Tooth Cervix / Q000000981:diagnostic imaging