INTRODUCTION: The aim of this study was to compare 3-dimensional landmark consistency and precision in skeletal structures in groups with different levels of experience with 2-dimensional cephalometrics.METHODS: Sixteen observers, all undergraduate or graduate students, were divided into 4 groups with different levels of experience in 2-dimensional landmarking and no previous experience in 3 dimensions. Group 1 consisted of 4 third-year dental students with no experience in cephalometric landmarking. Groups 2, 3, and 4 consisted of first-, second-, and third-year graduate students, with increasing levels of experience. The participants located 18 landmarks in 12 surface models of cone-beam computed tomography scans of patients on 3 separate occasions. The average of all examiners locating each landmark was defined as the centroid. The mean of the distances of each located point to the centroid of that landmark was used as the mean consistency (MC), and the standard deviation (SD) was used as the precision. Analysis of variance and post hoc Tukey comparisons between groups were done.RESULTS: The MC and SD values across landmarks, patients, and examiners were 1.03 ± 1.14 mm. The MC and SD were 0.89 ± 0.83 mm for group 1 with no experience, 1.02 ± 0.95 mm for group 2, 1.17 ± 1.60 mm for group 3, and 1.05 ± 1.00 mm for group 4. Significant differences were found among the groups.CONCLUSIONS: Comparing the observer groups studied, the undergraduate dental school students without previous experience in bidimensional cephalometrics obtained the best values in volumetric landmark location. Graduate students with increasing amounts of experience did not perform as well. These results and conclusions should be interpreted with caution because the number of subjects in each group was small.
Adolescent Anatomic Landmarks