The Ability of Different Observers in Measuring Dimensions of Objects and Cavities in Cone Beam-CT Images

Background: Accuracy of measurements obtained from cone-beam computed tomography (CBCT) images, which is a diagnostic tool in dentistry, is an important issue. The aim of this study was to compare the ability of different operators in measuring dimensions using CBCT software. Methods: In this experimental study, 35 different areas using opaque objects and drilling cavities were prepared on 3 phantoms which were made from fresh beef ribs. Then each phantom was scanned by CBCT Promax 3D. The mentioned areas were measured on CBCT images 2 times with one week interval by four observer groups consisting two radiologists, two periodontists, two maxillofacial surgeons, and two general dentists. Obtained measurements from each group of observers were compared with those of other groups and also with measurements of a digital caliper as a gold standard by intra-class correlation coefficient (ICC). Then the measured dimensions, with respect to their application, were divided into three clusters including cluster 1: 2-7 mm, cluster 2: 7-16 mm, and cluster 3: more than 16 mm. T test was used to compare the mean value of each cluster with the mean value of the gold standard. Results: In general, based on ICC, inter- and intra-observer agreement, agreement between observer groups, and agreement between each group and the gold standard were significant. The results of t test showed a significant difference between the mean value of data and that of gold standard in clusters 1 and 3. Conclusions: Generally, high accuracy and reliability were reported for different specialists of dentistry and general dentists in measuring the dimensions of objects and cavities in CBCT images.