Confusion exists in the orthodontic literature when the modulus of elasticity of standard orthodontic wire is reported to either increase, decrease, or remain constant when that wire is heat treated or work hardening.

The objectives of this work include: 1. Introducing the acoustic pulse-propagation technique as a test for determining the modulus of elasticity in orthodontic wire, and 2. Determining if the modulus of elasticity of stainless steel orthodontic wire changes when a wire is subjected to heat treatment and work hardening.

Five sizes of stainless steel wire were evaluated: .014, .016, & .018 inch round, .016 x .016 inch square, and .016 x .022 inch rectangular. Two groups were tested to determine the sonic modulus. The first group was tested 'as-received', and then retested after the wires were tensile loaded. The second group was tested after annealing (1700 degrees F. for 20 minutes). Retesting was done when the annealed wires were tensile loaded as in the first group.

Each wire was mechanically excited by a piezoelectric element. The piezoelectric received its amplified signal from, a square-wave pulse generator. The time-of-f 1 ight between two points on the wire was recorded and measured on a dual trace oscilloscope. The impulse time-of-flight range, from high to low, varied only .025 micro seconds. When converted to giga pascals, the measured elastic modulus varied 3.3% from the predicted value.

It was concluded that: 1. The acoustic pulse-propagation technique is a valid, reliable method for determining the modulus of elasticity of orthodontic wires, and 2. The modulus of elasticity of stainless steel orthodontic wire does not charge when the wire is subjected to heat treatment and work hardening.

LLU Discipline





Graduate School

First Advisor

Garland E. Scott

Second Advisor

Lawrence E. Will

Third Advisor

J. Milford Anholm

Fourth Advisor

M. Toufic Jeiroudi

Degree Name

Master of Science (MS)

Degree Level


Year Degree Awarded


Date (Title Page)




Library of Congress/MESH Subject Headings

Orthodontic Appliances -- utilization; Elasticity



Page Count

vii; 43

Digital Format


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.


Loma Linda University Electronic Theses and Dissertations

Collection Website



Loma Linda University. Del E. Webb Memorial Library. University Archives