Introduction: This study was intended to evaluate the accuracy of using panoramic radiographs to measure root length change over the course of orthodontic treatment, using intraoral scans of crowns, and a mathematical model to account for distortions in the radiographs. The study additionally evaluated whether a best-fit equation could be created from the calculated data to minimize differences to the measurements of root resorption made on CBCT scans. Materials and Methods: Twenty-one patients were selected who had comprehensive orthodontic treatment, and all teeth in the upper right quadrant were evaluated in this study. T1 and T2 CBCT images were compared and a change in root length was determined. T1 and T2 crown inclination changes were also measured on the CBCT scan. At T2, intraoral scans were taken of each arch and the crown heights of teeth of interest were measured. Probing depths at the direct buccal surface were recorded for teeth of interest. T1 and T2 panoramic radiographs were evaluated and a change in root length was calculated based on a mathematical model using a distortion ratio determined from measured intraoral scans of the crowns. Root resorption values were calculated by subtracting T1 total tooth length from T2 total tooth length. Results: Calculated root length change from panoramic radiographs had a trend towards being statistically significant compared to root length change when measured on CBCT scans. Using best curve equations, the disparity between the two classes of measurements could be accurately minimized, with the most accurate model fitting each tooth type individually with a unique quadratic equation. Adding probing depth and inclination changes into the mathematical models did not significantly increase accuracy. Conclusions: A clinically accurate mathematical model can successfully yield root length changes during orthodontic treatment based on measurements made on panoramic radiographs and intraoral crown length.

LLU Discipline

Orthodontics and Dentofacial Orthopedics


Orthodontics and Dentofacial Orthopedics


School of Dentistry

First Advisor

Viecilli, Rodrigo

Second Advisor

Caruso, Joseph M.

Third Advisor

Rungcharassaeng, Kitichai

Degree Name

Master of Science (MS)

Degree Level


Year Degree Awarded


Date (Title Page)




Library of Congress/MESH Subject Headings

Tooth -- radiography; Cone-beam Computed Tomography; Radiography - Panoramic; Orthodontics - Corrective;

Subject - Local

Root length measurement; Root length change; Orthodontic Treatment



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