Ray M. Hymer

Abstract

A cephalometric positioning device has been developed for use on the XRM Panorex X-Ray machine. Tests have demonstrated that the variability in producing serial radiographs with this device is comparable to, or less than, that currently accepted in conventional radiographic cephalometry.

Two procedures for obtaining serial radiographs were employed. Two patients were used for the first procedure and three patients were used in the second procedure.

In the first procedure each patient was positioned in the device and two radiographs were taken in sequence without disturbing the patient.

In the second procedure three clinic patients were used as subjects and three radiographs of each were taken in this manner. The patient was initially positioned with the apparatus, the positional settings were recorded and a radiograph made. The patient was then removed and all settings altered. The patient was then repositioned to the recorded settings by the same operator and a second radiograph was taken. Again the patient was removed and the settings altered. The recorded positional settings were then given to a second operator who positioned the patient and took a third radiograph.

The radiographs were superposed using, as reference points. the images formed by the metallic implants located in the external periphery of the bite fork. The observations were as follows: the two radiographs taken without disturbing the patient could be superposed with no visible differences.

In the second series of radiographs this was not the case. It was found that the subject could not be repositioned in relation to the metal implants accurately enough to use the implant images as reference guides for superpositioning of serial radiographs. Some of the series were, however, amazingly close. It was necessary to use the previously mentioned anatomic landmarks and superpose quadrant by quadrant. With this method, anatomical structures superposed without difficulty.

While the metallic implant images could not be used for serial superpositioning of radiographs in most instances, they were valuable for the evaluation of distortion. Further studies are necessary to quantify the complete distortion factors inherent with the Panorex radiograph.

LLU Discipline

Orthodontics

Department

Orthodontics and Dentofacial Orthopedics

School

Graduate School

First Advisor

Thomas J. Zwemer

Second Advisor

Howard W. Conley

Third Advisor

Alden B. Chase

Fourth Advisor

Ivan R. Neilsen

Degree Name

Master of Science (MS)

Degree Level

M.S.

Year Degree Awarded

1965

Date (Title Page)

6-1965

Language

English

Library of Congress/MESH Subject Headings

Radiography; Dental

Type

Thesis

Page Count

vi; 38

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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