The reliability and reproducibility of cephalometric measurements: a comparison of conventional and digital methods

Objective: The aim of this study was to assess the reliability and reproducibility of angular and linear measurements of conventional and digital cephalometric methods. Methods: A total of 13 landmarks and 16 skeletal and dental parameters were defined and measured on pre-treatment cephalometric radiographs of 30 patients. The conventional and digital tracings and measurements were performed twice by the same examiner with a 6 week interval between measurements. The reliability within the method was determined using Pearson's correlation coefficient (r(2)). The reproducibility between methods was calculated by paired t-test. The level of statistical significance was set at p < 0.05. Results: All measurements for each method were above 0.90 r(2) (strong correlation) except maxillary length, which had a correlation of 0.82 for conventional tracing. Significant differences between the two methods were observed in most angular and linear measurements except for ANB angle (p = 0.5), angle of convexity (p = 0.09), anterior cranial base (p = 0.3) and the lower anterior facial height (p = 0.6). Conclusion: In general, both methods of conventional and digital cephalometric analysis are highly reliable. Although the reproducibility of the two methods showed some statistically significant differences, most differences were not clinically significant. Dentomaxillofacial Radiology (2012) 41, 11-17. doi: 10.1259/dmfr/37010910