The realignment of teeth in the mouth requires the use of relatively low forces and moments applied continuously over extended periods of time.
The realignment of teeth in the mouth requires the use of relatively low forces and moments applied continuously over extended periods of time. The need for this force system to remain essentially constant while the repositioning is occurring suggests that the superelastic behavior of shape memory alloys could be utilized to advantage over conventional materials.
This work considers the simulation of shape memory alloy wires which are being utilized as orthodontic `springs’ to apply the necessary force systems to effectively move teeth. Through the use of a shooting technique the superelastic response of the material during both loading and unloading can be modeled and implemented in the numerical technique. Examples of specific orthodontic appliance designs which have been used with stainless steel and titanium alloys are simulated with NiTi shape memory alloy. The results show that even with existing designs the shape memory alloy wires could provide closer to ideal behavior than the more conventional materials.
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