Effect of experience in landmark identification on 2d lateral cephalograms on performance of dental students concerning landmark identification on 3d cone beam computed tomography scans

Abstract

Objective: To assess the effect of experience in landmark identification on two-dimensional (2D) lateral cephalograms on performance of dental students concerning landmark identification on three-dimensional (3D) cone-beam computed tomography (CBCT) scans. Material and Methods: This quasi-experimental study evaluated 40 dental students in two groups (n=20). Group 1 included senior dental students who had experience in landmark identification on 2D lateral cephalograms and Group 2 included third-year dental students with no such experience. Both groups received instructions on identification of eight landmarks on 3D CBCT scans. The coordinates of the landmarks were determined in x, y and z axes. One orthodontist determined the mean coordinates of each landmark as a reference by twice measurements with a one-week interval. The mean distance from the identified points to the reference points was reported as the mean consistency (MC), and the standard deviation of the mean was considered as precision of landmark identification. Data were analyzed using independent samples t-test. Results: The mean distances from the points identified as nasion, point B, orbitale, anterior nasal spine (ANS), menton, coronoid process and pogonion in x, y and z axes and point A in x and z axes (p<0.001) to the reference points in Group 1 were greater than those in Group 2 with no such experience. Conclusion: Previous experience in landmark identification on 2D cephalograms does not help in landmark identification on 3D CBCT scans and may even adversely affect the results.