Cephalometric regional superimpositions -- digital vs. analog accuracy and precision : 3. the cranial base

Objective. To assess the accuracy and precision in measurement of pairwise implant displacement across three methods of cranial base superimposition. Background. Cephalometric superimposition is the principal radiographic method used to evaluate changes within the craniofacial skeleton. Many studies have examined the accuracy of software intended to produce cephalometric superimposition. Such studies have utilized anatomic landmarks, selected by the respective software manufacturers, as registration points for constructing superimpositions and their analysis. As a result, these studies are only as accurate as the stability and validity of anatomic registration landmarks used. To our knowledge, no other study has utilized metallic implants to critically assess digital vs. analog cephalometric cranial base superimposition. Methods. Serial cephalograms from twenty-two patients across three time points containing metallic implants were obtained from the Mathews Acquisition Group. Each of the sixty-six cephalograms was traced by hand and digitally. Cranial base superimpositions were completed according to the analog structural method proposed by Björk and Skieller, and Johnston, and then by Dolphin version 11.5 and Quick Ceph Studio V3.2.8 digital software according to manufactures instructions. Total displacement measurements of selected implants across paired time points were recorded for both digital methods and analog method of superimposition with analog serving as the reference. Results: There were no statistically significant contrasts of mean total displacement of implants by superimposition method (p = 0.999). No significant differences are reported in mean implant displacement when comparing digital to analog superimposition methods for contrasts by time, structure, or implant location. Conclusions: The results show that there are no significant differences in accuracy and precision of digital and analog cranial base superimposition. The results of this study suggest that cranial base superimpositions on S-Na that are registered on S may be a good approximation of the structural method of cranial base superimposition. There are many methodological differences between digital and analog cranial base superimposition and future research examining such differences is recommended