Abstract

Fracture of orthodontic appliances can be a problem because of the time involved to replace and repair them. It has been shown that most failures have been a result of fatigue fracture, i.e., failure resulting from cyclic loading.

The purpose of this study was to determine what effect variation of the type of orthodontic wire and heat treatment had on fatigue resistance. A device was constructed to put a cyclic load on a piece of wire until fracture. Two types of cobalt-chromium alloy wire (Blue and Green Elgiloy from Rocky Mountain Orthodontics) and three types of stain less steel wire (Tru-chrome from Rocky Mountain Orthodontics, Permachrome Standard and Hi-T from Unitek Corporation) were studied in as-received and heat—treated conditions. The results showed a wide variation in the fatigue resistance. Heat treatment affected only Green Elgiloy significantly by decreasing fatigue resistance 36%.

In the low cycle, nonheat-treated group, Tru-chrome had the poorest fatigue resistance while Green Elgiloy was the most fatigue resistant. In the heat-treated group, again Tru-chrome was the least fatigue resistant. However, none of the types was clearly superior.

LLU Discipline

Orthodontics

Department

Dentistry

School

Graduate School

First Advisor

Jack L. Tomlinson

Second Advisor

J. Milford Anholm

Third Advisor

Norman S. Carter

Fourth Advisor

Alden B. Chase

Fifth Advisor

Guy D. Taylor

Degree Name

Master of Science (MS)

Degree Level

M.S.

Year Degree Awarded

1979

Date (Title Page)

6-1979

Language

English

Library of Congress/MESH Subject Headings

Orthodontic Appliances

Type

Thesis

Page Count

vi; 35

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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