Accuracy of Unsegmented CBCT in Mesial-Distal Tooth Measurements

Introduction: Cone-beam computed tomography (CBCT) scans may be used to measure mesial-distal (MD) tooth width for orthodontic diagnosis and treatment planning. Purpose: The objective of this study was to determine if MD tooth measurements from unsegemented CBCT scans in the axial, sagittal, and coronal planes or from a panoramic reconstruction correlate and agree with respective measurements made on study models. Material and Methods: Using stone models of 30 subjects, reference MD tooth measurements were made using digital calipers. From CBCT scans, five different methods of measuring MD width were used and compared to the reference: (1) points chosen from orthogonal planar views using a custom plugin for OsiriX, (2) points chosen from a simple panoramic image made in OsiriX and (3) Dolphin, and finally, (4) points from a detailed panoramic image made in OsiriX and (5) Dolphin. Statistical Analysis: An Intra-class correlation (ICC) was used to compare resulting MD measurements from the five different measurement methods to the model measurements. Ten subjects were re-measured for reliability using Cronbach\u27s Alpha. Box-whisker plots were used to visualize results. Results: At a statistically significant level, measurements made from reconstructed panoramic films and from orthogonal planar views show high correlation and agreement with reference measurements. A detailed panoramic cut line produced more accurate measurements than a simple cut line. Anterior tooth measurements were more variable. Conclusions: MD tooth widths can be accurately measured from CBCT scans. Care must be taken in how panoramic slices are constructed and how the data is measured