Abstract

The purpose of this investigation was to develop methods and equipment to measure and record over any desired length of time the loss or gain in force of any material used in orthodontics that can produce a force upon an object. The material and the object being acted upon should not be disturbed while measuring that force.

Holding devices were designed and constructed in two basic forms. For intrusive and extrusive type forces, a load cell was fixed horizontally in such a position that an adjustable tube with a set screw to hold the wire could be rotated to cause the free end of the wire to produce force upon the load cell. The load cell was connected to a transducer indicator with an L.E.D. display that was programmed to read out the force in grams. For retrusive (retraction) or protrusive type forces, the load cell was fixed in a vertical position, and the tube holding the wire or other material to be tested could be moved closer to the load cell with the appliance attached to produce protrusive force, or pulled further away from the load cell with the appliance attached such that retrusive force was produced. Either appliance could be set in a fixed position, and the object to be tested could be inserted into special brackets, and thus for the specific design of the object being tested, the act of inserting or connecting the object to be tested would put the force into action that could be read on the L.E.D. display. The load cell and transducer indicator continuously monitor the force such that at any desired time, the remaining force applied by the object being tested may be noted.

To test the experimental design, .016" x .016" samples of Unitek Standard Permachrome stainless steel square wire12, American Orthodontics Multiphase square wire, and Rocky Mountain Orthodontics Blue Elgiloy square wire were obtained. The first series of tests were performed on straight sections of wire cut to equal lengths, after which a second series of tests were performed on wires formed into equally sized sectional utility arches. Following the tests on these three types of wires, the blue Elgiloy was heat treated and tested again in these same configurations to see if the experimental design would show any difference of rate of decay by heat treating the wire.

The results of single samples show the trend of untreated blue Elgiloy dropping rapidly in force during the first six minutes, then rounding out to drop gradually after the first hour. Heat treated blue Elgiloy showed a tendency to gain slightly in force over the first three days. The sectional utility was heat treated at the same time as the straight section of blue Elgiloy, and not tested until the end of the two weeks test of the straight section. It in effect was a continuation of the straight blue Elgiloy heat treated test and held more or less steady throughout the entire two weeks of its test. The stainless steel showed a tendency for a slight gradual type of loss of force over the two week period. The multiphase wire showed a slightly higher rate of loss than the stainless steel wire.

Single samples were tested as a test for the experimental design only, rather than to compare certain wire properties, thus the results listed cannot be used to compare the wires scientifically. To do that, multiple samples of each wire must be tested to obtain means and standard deviations. The tests do indicate that the method designed will indeed measure forces continuously without disturbing the appliances or materials being tested. The rate of load loss or gain can now be measured in the laboratory to determine the inherent stability of various orthodontic force producing materials by analyzing the data obtained in multiple tests of the desired material. For multiple experiments, a logging multimeter is available that will monitor and print out in sequence the output of four load cells either manually, or by an automatic programmable timer, but was not available for this test.

LLU Discipline

Orthodontics

Department

Dentistry

School

Graduate School

First Advisor

Donald R. Schmitt

Second Advisor

J. Milford Anholm

Third Advisor

James R. Wise

Fourth Advisor

Virgil V. Heinrich

Fifth Advisor

Clelan G. Ehrler

Degree Name

Master of Science (MS)

Degree Level

M.S.

Year Degree Awarded

1980

Date (Title Page)

6-1980

Language

English

Library of Congress/MESH Subject Headings

Orthodontic Appliances

Type

Thesis

Page Count

v; 28

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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