Intraexaminer and interexaminer reliabilities of landmark identification on digitized lateral cephalograms and formatted 3-dimensional cone-beam computerized tomography images.

INTRODUCTION: The purposes of this study were to determine and compare the intraexaminer and interexaminer reliabilities of commonly used cephalometric landmarks identified on digitized lateral cephalograms and formatted cone-beam computerized tomography (CBCT) images.
METHODS: CBCT images from 10 randomly selected adolescent patients were obtained from the orthodontic records of a private practice. Measurement errors, and intraexaminer, and interexaminer reliability correlation coefficients (ICC) were obtained for all landmark coordinates.
RESULTS: Intraexaminer and interexaminer reliabilities for all coordinates for most landmarks on the digital lateral cephalograms and CBCT images were greater than 0.9 (ICC value). The means of landmark locations differed by approximately 1 mm in most coordinates from the lateral cephalograms and were predominantly higher than 1 mm for all coordinates from the CBCT images.
CONCLUSIONS: Intraexaminer and interexaminer reliabilities were high for most landmarks. Coordinates with greater measurement errors in the lateral cephalograms (condylion, gonion, porion, mandibular incisor apex, and posterior nasal spine) were in structures without clearly defined borders. In the CBCT images, gonion, condylion, and porion were located on surfaces that were flat or curved, making it difficult to recognize a specific reference point. Other less reliable landmarks (anterior nasal spine, posterior nasal spine, mandibular incisor apex) were located in structures with lower densities and could not be visualized with 3-dimensional reconstruction; thus, they had high measurement errors. Copyright (c) 2010 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.