Observer Reliability in identification of Three-Dimensional Cephalometric Landmarks on CBCT Images

An important step before establishing CBCT as a common orthodontic diagnostic approach is to assess landmark reliability. The purpose of the present study was to evaluate intra- and inter observer reliability in 3D landmark identification using CBCT images.

A total of 30 CBCT images were selected for this experimental study. Working independently، two observers identified 14 landmarks، twice in the CBCT images. Selecting the most appropriate slice in the axial، coronal، and sagittal views، the position of the landmark was recorded in millimeters for the X، Y، and Z coordinates respectively. Intra- and inter observer reliability values were determined using Pearson’s correlation test.

The Intra class correlation (ICC) was >0. 7 for 97. 6% of intra observer assessments and 92. 8% of inter observer assessments. None of the ICCs were <0. 6. The ICC was ≥0. 9 for 25 (59. 5%) of the intra observer assessments. The ICC was ≥0. 9 for 28 (66. 67%) of the inter observer assessments. The mean differences between the two observers in 95. 2% of the cases were less than 2 millimeters.

Considering the limitations and the results of the present study، the intra- and inter observer reliability was high. With proper training of the operator، the three-dimensional landmark identification using CBCT can offer consistent and reproducible data.