Abstract

Force relaxation was constantly monitored in light titanium alloy and stainless steel wires over a 7 day period in a simulated use test. The smallest dimension of round titanium wires now available were matched with round stainless steel wires in dimensions that most closely approximated the same stiffness. The .016" NITINOL (Unitek) and TITANAL (Lancer Pacific) wires were compared to .012" Standard Permachrome (Unitek) wire. The .016" TMA (Ormco) wire was compared to .014" Standard Permachrome (Unitek) wire. Six samples were tested for each wire type.

Each wire was ligated with Alastic modules (Unitek) into .018" x .025" slots of brackets bonded from first molar to first molar on a mandibular typodont with ideal occlusion. The right central received no bracket thus providing a 10 mm test span of wire where a static 1 mm deflection was applied vertically downward at the midpoint by a steel rod extending from a minibeam load cell.

Though 1 mm deflections are commonly placed in these light flexible wires in orthodontic mechanics, the immediate result evidenced was a very high initial force ranging from 528 to 1085 grams depending upon the wire type. This is a factor of 21 to 41 times the amount of force recommended by Reitan (1957) to use in extruding teeth. This strongly suggests caution when using even the lightest dimensions of titanium alloy wires as initial leveling wires.

Force relaxation was highest during the early minutes. Before one hour had elapsed all of the wires lost over half of the overall force lost during the 7 day period. The total mean force relaxation occurring over the 7 day test period ranged from 6.92% to 10.83 % for the 5 wire types tested. This amount of force relaxation, when extrapolated out based upon the force lost during the last 72 hours of the test, suggests that all 5 wire types tested would exhibit force production in the physiologic range for tooth movement at the end of 6 weeks.

LLU Discipline

Orthodontics

Department

Dentistry

School

Graduate School

First Advisor

James R. Wise

Second Advisor

Joseph Caruso

Third Advisor

Clelan G. Ehrler

Fourth Advisor

John E. Peterson

Fifth Advisor

Garland E. Scott

Sixth Advisor

Roland D. Walters

Seventh Advisor

Grenith J. Zimmerman

Degree Name

Master of Science (MS)

Degree Level

M.S.

Year Degree Awarded

1984

Date (Title Page)

8-1984

Language

English

Library of Congress/MESH Subject Headings

Orthodontic Appliances; Metals -- analysis

Type

Thesis

Page Count

2 vii; 63

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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