title: Accuracy of measuring the cortical bone thickness adjacent to dental implants using cone beam computed tomography.
abstract: OBJECTIVE
  To assess the accuracy of measuring the cortical bone thickness adjacent to dental implants using two cone beam computed tomography (CBCT) systems.
  
  
  METHODS
  Ten 4 x 11 mm Astra Tech implants were placed at varying distances from the cortical bone in two prepared bovine ribs. Both ribs were scanned in a reproducible position using two different CBCT scanners. Ten examiners each carried out four measurements on all 10 implants using the two CBCT systems: vertical distance between the top of the implant and the alveolar crest (IT-AC), and thickness of the cortical bone from the outer surface of the implant threads at 3, 6 and 9 mm from the top of the implant. Ground sections were prepared and bone thickness was measured using a light microscope and a graticule to give a gold standard (GS) measurement.
  
  
  RESULTS
  The examiner's measurements were significantly different between CBCT systems for the vertical and thickness dimensions (P<0.001) while measuring the cortical bone thickness between 0.3 and 3.7 mm. Within that range, i-CAT NG measurements were consistently underestimated in comparison with the GS. Accuitomo 3D60 FPD measurements closely approximated the GS, except when cortical bone thickness was <0.8 mm. The mean percentage errors from the GS at 3, 6 and 9 mm measurement levels were 68%, 28% and 18%, respectively, for i-CAT NG and 23%, 5% and 6%, respectively, for Accuitomo 3D60 FPD.
  
  
  CONCLUSIONS
  Within the limitations of this study, it was concluded that i-CAT NG (voxel size 0.3) may not produce sufficient resolution of the thin cortical bone adjacent to dental implants and, therefore, the measurements may not be accurate; whereas, Accuitomo 3D60 FPD (voxel size 0.125) may produce better resolution and more accurate measurement of the thin bone.
authors.affiliation: Department of Restorative Dentistry, King's College London Dental Institute, London, UK.
authors.forename: Touraj
authors.initials: T
authors.lastname: Razavi
authors.forename: Richard M
authors.initials: RM
authors.lastname: Palmer
authors.forename: Jonathan
authors.initials: J
authors.lastname: Davies
authors.forename: Ron
authors.initials: R
authors.lastname: Wilson
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Palmer
mesh_terms: D000539:Alveolar Process / Q000000981:diagnostic imaging*; D000818:Animals; D015519:Bone Density / Q000502:physiology*; D002417:Cattle; D054893:Cone-Beam Computed Tomography / Q000295:instrumentation*; D015921:Dental Implants; D012016:Reference Values; D012272:Ribs / Q000601:surgery
chemical_list: D015921:Dental Implants