FIG. 1.

Nonplanarity of the SCCs. Least squares “flat” planes were fitted to the centroid paths of each of the SCCs as shown in A. To demonstrate canal nonplanarity, a second-order polynomial was used to also fit a “curved” plane shown in B. This comparison clearly demonstrates nonplanar components of each SSC. C Resliced CT images for each of the planar (FP) and nonplanar (CP) fits. The flat plane slices appear to be good; however, the “curved plane” images show a canal with a higher level of contrast for the entire path. This is because the curved plane passes closer to the centerline of the canal, while the former result can often be deceptive due to the thickness of the canal. The radius of each particular canal is provided to indicate scale in comparison to the original resolution of 0.5 mm. Note that the resliced curved plane images have a non-uniform scale due to the nature of the curved space mapping.