Abstract

The purpose of this research was to compare the accuracy of angular measurements of the panoramic image of the Newtom 9000™ Cone Beam Computed Tomography (CBCT) with the Sirona™ Orthophos panoramic unit. The study was separated into three parts: phantom study, patient study, and archform study. The phantom study used fabricated phantom typodonts to compare angular measurements between the Newtom 9000™ panoramic image and the Sirona™ panoramic radiograph. Accuracies of the measurements were then determined by comparing the values to the actual phantom typodont. No marked differences in angular measurements were recorded for the phantom typodont using either of the two imaging systems. Errors in fabricating the phantom typodont contributed to the results obtained.

For the patient study, retrospective angular measurements were made using previously taken panoramic radiographs and Newtom 9000™ scans of 60 patients undergoing orthodontic treatment at Loma Linda University. The patient study demonstrated significant differences between the Newtom 9000™ and the Sirona™ measurements. In the maxilla, the area of greatest difference was in the cuspid-premolar region, and the area of least difference was in the anterior and posterior region. In the mandible, the area of greatest difference was in the posterior region and the area of least difference was in the anterior region. Factors that contributed to these results include: 1) differences of head position, 2) bucco-lingual angulation of the roots, and 3) distortions inherent to panoramic radiographic imaging.

The archform study determined if arch width and arch depth had any correlation to the mesial-distal radiographic dimensional width of the first molar. The assumption was that patients with wider vs. narrower arch width, and shorter vs. longer arch depth would have a diminution in radiographic image dimensions. Research was conducted using 41 sets of models from 60 patients used for the second part of this study. Results showed no correlation in arch width to radiographic molar width. A possible explanation for these results could be the temple caliper device on the Sirona™ panoramic unit. The device automatically adjusts the trough size according to patient skull size, thereby eliminating any existing correlation. For arch depth to molar dimensional width correlation, there was a statistical correlation on the left side of the arch only. One possible explanation is due to improper head positioning in the head holder of the panoramic unit. When this occurs, the midline of the patient is slightly turned to one side, resulting in magnification on that side.

Linear dimensional measurements of the mandibular first molars were then compared between the Newtom 9000™ panoramic image and the Sirona™ panoramic radiograph to the patient model to determine the dimensional accuracy. The dimensional measurements of the Newtom 9000™ were statistically similar to the model measurements. It was therefore concluded that the Newtom 9000™ dimensions, including angular dimensions, are much more accurate than those of Sirona™ angular dimensions.

LLU Discipline

Orthodontics and Dentofacial Orthopedics

Department

Orthodontics and Dentofacial Orthopedics

School

Graduate School

First Advisor

Joseph M. Caruso

Second Advisor

Mark Batesole

Third Advisor

Jay Kim

Fourth Advisor

Leroy Leggitt

Degree Name

Master of Science (MS)

Degree Level

M.S.

Year Degree Awarded

2004

Date (Title Page)

12-2004

Language

English

Library of Congress/MESH Subject Headings

Radiography, Dental -- methods; Diagnostic Imaging -- methods; Tomography, X-Ray Computed -- methods

Type

Thesis

Page Count

x; 45

Digital Format

PDF

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.

Collection

Loma Linda University Electronic Theses and Dissertations

Collection Website

http://scholarsrepository.llu.edu/etd/

Repository

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

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