Soft tissue images from cephalograms compared with those from a 3D surface acquisition system

To assess whether 2D cephalometrics is comparable with 3D imaging devices and whether 3D technology could replace traditional 2D image capture in posttreatment evaluation.

The study is a prospective evaluation of superimposition techniques obtained from a cohort of 40 patients who underwent orthognathic surgery in a private practice environment. Surgical records were obtained from lateral cephalometric radiographs taken by a Kodak 8000C machine, and the 3D images were obtained from the 3dMD stereo photogrammetric camera capture system. Pre- and postlateral cephalometric records were superimposed on the cranial base (SN line) while pre- and post-3D surgical records were superimposed on the regional best-fit method. A mathematical algorithm, or best-fit calculation, was carried out on the selected surfaces. Each set of superimposed records was analyzed, and five soft tissue landmarks were plotted. The differences between the five surface points were analyzed for each set of records.

The final sample consisted of 34 subjects with full records. A total of 680 surface landmarks were plotted and analyzed. The mean differences of the soft tissue landmarks were analyzed for each pair of data sets and were found to range between 1.06 and 8.07 mm and 1.26 and 7.34 mm for lateral cephalometric and 3D readings, respectively. Paired t-tests were carried out using the SPSS 15.0 software, and they showed that the results were not statistically significant between the superimposition techniques on the image capture systems (P > .05).

The types of superimposition techniques used in the imaging modalities studied were comparable with one another.