Objectives: The purpose of this experimental study was to test the accuracy of measuring the size of not yet erupted porcine tooth germs via cone beam computed tomography (CBCT) by comparing its results to the mesio-distal diameters determined clinically after surgical removal.
Methods: Using the anatomical mesial and distal contact points, the maximum diameters of 22 impacted teeth were first determined via CBCT. Then, following osteotomy, teeth were measured directly with calliper. Measurements were taken by three independent examiners twice leaving an interval of 14 days in between. Statistical analysis revealed the accuracy of these measurements as well as the repeatability and the reproducibility.
Results: The total standard deviation was 0.10 mm when using sliding callipers compared to 0.16 mm using CBCT. Repeatability of direct clinical measurements was almost twice as good (factor 1.6) as the CBCTs and thus significantly better (p<0.001) than the measurements obtained by means of 3D-radiography (MSCT: 0.11 mm vs. CBCT: 0.16 mm). The Bland-Altman plot revealed that different measurement results were not dependent on the measurements' absolute value. On average, the use of CBCT yielded values 0.26 mm smaller than those obtained from direct measurement.
Conclusions: Prospective determination of impacted teeths' mesio-distal diameter via CBCT can be performed in a sufficiently accurate way even when compared to direct clinical measuring. This is of vital importance to orthodontic treatment planning, most notably the assessment of available space and actual anchorage situation.