ELASTIC ENERGY STIFFNESS RATIOS FOR SELECTED ORTHODONTIC WIRES

This investigation determined the ratio of the energy available for or thodontic tooth movement to the stiffness and flexibility of a given w ire. Twenty-five specimens each of five brands of orthodontic wire wer e tested in tension in the as-received condition. Force versus elongat ion diagrams were obtained and then converted into stress-strain data. Mean values were determined for the yield strength and yield strain f or each brand of wire. The, modulus of elasticity (E), modulus of resi lience (R), and elastic compliance (C) were then calculated. Two ratio s were established by using the three mechanical properties: (1) the m odulus of resilience/modulus of elasticity (R/E) ratio and (2) the mod ulus of resilience/elastic compliance.(R/C) ratio. The results confirm ed that the use of these two ratios in combination permitted one to di fferentiate among the various types of orthodontic wires, with respect to stored energy and its relationship to the stiffness or flexibility of the wire.