Comparison of two cone beam computed tomography multiplanar reconstruction orientation protocols

Objective: The utilization of cone beam computed tomographic imaging for oral implants has increased enormously for precise determination of anatomic dimensions. However, the impact of reorientation of data that influences the constructed panoramic view and thus the measurements on generated cross sectional views has not been explored. This study is undertaken to explore if differences exist in the implant height and width measurement when the whole data is reoriented from the standard manufacturer's setting to an aligned protocol (perpendicular to the implant (XYZ) settings). Material and Methods: Two different orientation protocols were set up, standard and aligned or perpendicular setting (XYZ), and implant height and width measurements derived from these were compared to the original known measurements. Results: The range of differences between actual dimensions and measurements obtained using each orientation method using McNemar's Change test in the four accuracy categories (exact, +0.20, +0.25, and +0.50) showed the aligned orientation produced larger proportion of width measurements between +0.25 and +0.50 compared to standard for width measures; however, these differences were not statistically significant. Implant length measurements varied widely and this variability was irrespective of orientation method. Conclusions: The aligned/perpendicular (XYZ) protocol produces implant width measurements more accurate than length when compared to the standard protocol.