A Study of Forces Exerted by the Orthodontic Archwire and its Auxiliaries

Abstract

The object of this study was the determination of the amount of force exerted by some of the simpler widely-used orthodontic appliances. More specifically, interest was centered on the rate of force delivery, as well as upon the nature of the stresses induced in the various parts of the wires. By using experimentally determined values of the modulus of elasticity and the appliance dimensions the forces and corresponding deflections of these simpler orthodontic structures may be calculated. Theoretical force determinations according to the methods employed in the science of strength of materials were made on the following appliance forms: the finger spring; the simply supported wire; the semicircular wire form; and the U-Shaped arch. Force values and corresponding displacement measurements were made on samples of various sizes of round and rectangular wires. Comparison of these measurements with the calculated values indicated very good agreement.