Objective: With the introduction of 3D imaging in orthodontics attempts have been made to match 3D radiographic images of the hard tissues with photographs of the soft tissues. The objective of this experimental study was to evaluate the validity of a novel device which acquires simultaneously in one scan a cone-beam CT (CBCT) and textured skin surface.
Methods: We obtained simultaneous CBCT scans and 3D photograph in one single rotation of a phantom using a GALILEOS® device (Sirona Dental Systems, Germany) to which a 3D laser scanning device had been added. A novel registration method based on the simultaneous acquisition and calibration was used to match both datasets. Markers for marker based registration were additional placed on the phantom. The accuracy of registration of the untextured surface (CBCT) and textured skin surface (3D photograph) was assessed and compared to marker based registration using surface distance measurements.
Results: The results showed that a full-face surface model can simultaneously be acquired with a CBCT. No difference in mean absolute error between the scan settings was found in the surface distance colour maps. The average absolute error between the marked reference points was less than 1 mm to the unmarked image. Dispersion was relatively large around existing curvatures, e. g. the eyes, ears and the neck.
Conclusions: With the novel device a CBCT and simultaneous textured skin surface can be obtained in one single rotation scan and the 3D surface image used for sufficient clinical use.