Introduction: The increased dimensional accuracy of images provided by cone beam computed tomography (CBCT) scans allows for more in-depth diagnosis and treatment planning. Expedient interpolation of segmented data that provides clinically acceptable results will encourage clinicians to frequently use CBCT images for clinical/radiographic evaluation. Some of these applications include, quantification of root resorption, determination of force required for specific tooth movements, and customized appliances. Purpose: The study had two purposes. The first was to compare the accuracy of digital tooth volumes acquired from CBCT to the gold standard, micro-computed tomography (micro-CT). The second was to determine the effect of axial slice reduction on volume interpolation, using two different interpolation methods. Materials & Methods: Five unrestored, single-rooted teeth underwent micro-CT and CBCT scanning. The data was reconstructed and imported into Simpleware™ ScanIP for segmentation and volumetric analysis. Segmentation was completed, resulting in a mask, which then underwent sequential root reduction. Two interpolation methods, Three Dimensional (3D) Wrap and Interpolation Toolbox, were applied to each reduction mask. The volume, length, voxel count, and grayscale values of each method were evaluated.

Statistical analysis was performed using intraclass correlation coefficient (ICC) tests to examine intraexaminer reliability, Friedman’s Analysis of Variance by Ranks to evaluate the mean difference between micro-CT and CBCT, Wilcoxon Signed Rank Test to evaluate the reduction differences between two CBCT resolutions, and Kruskal-Wallis test to evaluate the differences in reduction within each CBCT resolution. The significance level of all statistical analysis was set at  = 0.05. Results: The volume comparisons between micro-CT and CBCT scans showed statistically significant differences (p = 0.015), however, pairwise comparison revealed the difference to be between the two resolutions of CBCT scans and not between CBCT and micro-CT. With regard to sequential reductions and interpolation accuracy, the 3D Wrap method had a greater tendency toward underestimation while the Interpolation Toolbox method provided more accurate measurements. Conclusions: Due to small sample size and statistically significant differences between overall mean volume measurements, it cannot be concluded that micro-CT and CBCT scans produce the same volume. Interpolated digital tooth volume obtained from axial reductions was more accurate with the Interpolation Toolbox method, than the 3D Wrap method. It can be concluded that the Interpolation Toolbox method would be beneficial for tooth volume assessment in a clinical setting.

LLU Discipline

Orthodontics and Dentofacial Orthopedics


Orthodontics and Dentofacial Orthopedics


School of Dentistry

First Advisor

Caruso, Joseph M.

Second Advisor

Olson, Gregory W.

Third Advisor

Rungcharassaeng, Kitichai

Degree Name

Master of Science in Orthodontics and Dentofacial Orthopedics (MSODO)

Degree Level


Year Degree Awarded


Date (Title Page)




Library of Congress/MESH Subject Headings

Cone-Beam computed Tomorgraphy; Orthodontics; Radiography-Dental

Subject - Local

Root Volumes; Limited Segmentation; Volumetric Analysis



Page Count


Digital Format


Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.


Loma Linda University Electronic Theses and Dissertations

Collection Website



Loma Linda University. Del E. Webb Memorial Library. University Archives