title: Accuracy and reproducibility of four cone beam computed tomography devices using 3D implant-planning software.
abstract: OBJECTIVE
  To measure the deviations of four different cone beam computed tomography (CBCT) devices in three dimensions by means of a three-dimensional (3D) implant-planning program.
  
  
  METHODS
  A master radiographic template with two vertical, two transverse, and two sagittal radiopaque markers was fabricated for a human dry skull. The lengths of the markers were measured with a high-precision caliper. The skull and the template were scanned in each of the four CBCT devices (1. Gendex GXCB-500; 2. Sirona Galileos Comfort; 3. Sirona Orthophos XG 3D; 4. Carestream CS 9300) 19 times (10 scans without moving the skull, and 9 scans with repeated repositioning of the skull in the device, according to the manufacturers' instructions). A 3D implant-planning program was used to measure the lengths of the six markers digitally. Actual and digital measurements were compared to determine device-specific errors. The repositioning of the skull examined the reproducibility of the CBCT devices. Linear measurements were analyzed statistically (P < 0.05).
  
  
  RESULTS
  Mean deviations without moving the skull (vertical/sagittal/transverse) for device 1 were 0.023 mm/ 0.000 mm/0.025 mm (0.07%/0.19%/0.24%), for device 2 were 0.410 mm/0.115 mm/0.080 mm (-1.75%/0.32%/ 0.88%), for device 3 were -0.665 mm/-0.215 mm/ -0.675 mm (-2.71%/-1.82%/-4.42%), and for device 4 were -0.045 mm/-0.135 mm/-0.410 mm (-0.45%/ -1.54%/-2.57%). The overall mean deviation for device 1 was 0.028 mm (0.16%), for device 2 was 0.072 mm (-0.95%), for device 3 was 0.518 mm (-2.97%), and for device 4 was -0.197 mm (-1.53%). The mean deviation after repositioning for device 1 was 0.004 mm (-0.65%), for device 2 was -0.250 mm (0.95%), for device 3 was 0.496 mm (-2.66%), and for device 4 was -0.265 mm (-1.92%). Thus, apart from device 3, the deviations increased.
  
  
  CONCLUSIONS
  Deviations from the actual measurements were detected with each device. Therefore, respecting safety distances when placing implants is crucial.
authors.forename: Michael
authors.initials: M
authors.lastname: Stimmelmayr
authors.forename: Katharina
authors.initials: K
authors.lastname: Denk
authors.forename: Kurt
authors.initials: K
authors.lastname: Erdelt
authors.forename: Gerald
authors.initials: G
authors.lastname: Krennmair
authors.forename: Sonia
authors.initials: S
authors.lastname: Mansour
authors.forename: Florian
authors.initials: F
authors.lastname: Beuer
authors.forename: Jan-Frederik
authors.initials: JF
authors.lastname: Güth
mesh_terms: D054893:Cone-Beam Computed Tomography / Q000295:instrumentation*; D003757:Dental Implantation / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D012984:Software; D025321:Surgery, Computer-Assisted / Q000379:methods*