Abstract
Objective: The 3 DX Multi Image Micro CT (3 DX) is a novel X-ray CT used limited cone beam. This study has determined the reproducibility among observers and accuracy in measurement of the size of an extracted tooth on the 3 DX images.
Methods: An impacted supernumerary tooth extracted from the median maxilla was the subject of this study. The width and length of the tooth on the 3 DX images were measured 5 times by 5 individual observers. Significant differences in values among the observers in the measuring distance between 2 points on an image without opaque spots (Image 1) were determined by one way ANOVA for examining reproducibility. In addition, the coefficients of validity (CVs) were calculated from the values associated with Image 1 and those associated with the other image with the opaque spots (Image 2). They were compared respectively to the CV obtain as control with a digital caliper (DC) using Wilcoxon's T-test for examining accuracy.
Results: Of the measured values pertaining to Image 1, there was no significant difference among the observers (p>0.05). The CVs associated with both images were significantly higher than the CV associated with DC when the width was measured (p<0.05). On the other hand, the CVs associated with both images were not significantly higher than the CV associated with DC when the length was measured (p<0.05).
Conclusions: High reproducibility was obtained in measuring the size of tooth on the 3 DX image. High accuracy was detected in measuring the length of the tooth. Low accuracy was detected however, in measuring the width of the tooth, suggesting that repeated measurement is necessary to minimize variation of the width of the tooth.
