title: Accuracy of radiographic measurements for implant planning using cone-beam and helical computer tomography.
abstract: OBJECTIVE
  The aim of the present study was to compare the accuracy of radiographic measurements for dental implants planning using cone-beam computed tomography (CBCT) and helical computed tomography (HCT).
  
  
  METHODS
  Six pig ribs were wrapped by putty impression material, with radiographic markers placed. Two CBCT and an HCT were taken following the standard protocols. Twenty-five locations were selected, with vertical and horizontal dimensions measured using the default software, as well as on the processed HCT films by a digital caliper. The actual dimensions of the ribs measured by the digital caliper served as the control. Differences between radiographic dimensions and the actual dimensions were tested by two-way analysis of variance.
  
  
  RESULTS
  No differences were found between measurements made by CBCT and HCT images using the default software (P > 0.05). However, both measurements were statistically-significantly lower than the control (P < 0.001), and the mean difference was 0.3 mm. Measurements made on HCT films were statistically-significantly greater than the control (P < 0.001), and the mean difference was 0.5 mm.
  
  
  CONCLUSIONS
  The accuracy of CBCT and HCT are similar, and both are reliable tools for implant planning. It is preferable to perform the planning using default software, rather than making direct measurements on films.
authors.affiliation: Comprehensive Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China.
authors.forename: Carl K K
authors.initials: CKK
authors.lastname: Leung
authors.affiliation: Oral Rehabilitation, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China.
authors.forename: Edmond H N
authors.initials: EHN
authors.lastname: Pow
authors.affiliation: Oral Radiology, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China.
authors.forename: Thomas K L
authors.initials: TKL
authors.lastname: Li
authors.affiliation: Dental Public Health, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China.
authors.forename: Edward C M
authors.initials: ECM
authors.lastname: Lo
authors.affiliation: Comprehensive Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China.
authors.forename: Tak W
authors.initials: TW
authors.lastname: Chow
mesh_terms: D000818:Animals; D054893:Cone-Beam Computed Tomography; D003758:Dental Implantation, Endosseous / Q000379:methods*; D061827:Dimensional Measurement Accuracy; D013552:Swine; D013813:Therapy, Computer-Assisted; D036542:Tomography, Spiral Computed
keywords: accuracy; cone-beam computed tomography; dental implant; helical computed tomography; pre-operative planning