Abstract

A computer model of a human maxillary central incisor was devised to predict the momentary center of rotation of a tooth when a force was applied to the crown. The root of a tooth was divided up into a series of small segments to simulate the resisting forces set up along the root by the periodontal fibers. Each segment was assumed to resist a force in proportion to its area.

To study a tooth in a state of static equilibrium, two conditions must be met. The vector sum of all the forces acting on the tooth must equal zero, and the sum of all the torques must equal zero. The area of each segment and its relation to the center of rotation were used along with the two conditions of static equilibrium to compute a momentary center of rotation.

When a force was applied four millimeters from the incisal edge of eight teeth, the computed center of rotation averaged close to the middle of the root. The center of resistance for the same teeth averaged about six-tenths of the length of the root from the apex.

The angle through which the tooth rotated for a given force was calculated trigonometrically by recording the displacement of a long lever arm of light. An average angle of rotation for each tooth was used to compute for a constant that was dependent on the coefficient of elasticity of the periodontal membrane.

LLU Discipline

Orthodontics

Department

Dentistry

School

Graduate School

First Advisor

Alden B. Chase

Second Advisor

Ivan R. Neilsen

Third Advisor

J. Mailen Kootsey

Fourth Advisor

Steve N. Asahino

Degree Name

Master of Science (MS)

Degree Level

M.S.

Year Degree Awarded

1967

Date (Title Page)

6-1967

Language

English

Library of Congress/MESH Subject Headings

Incisor

Type

Thesis

Page Count

iv; 48

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

Download

Share

COinS