Development Of A Process For Programming Local Pseudoelastic Properties In An Orthodontic Archwire

A novel approach for treating malocclusions in orthodontic treatment has been developed using CuNiTi wires that have been processed using a laser treatment to locally tune the pseudoelastic properties. This new archwire is capable of simultaneously delivering different forces to individual malposited teeth given a similar activation distance. Using this technology, the archwire can express the ideal biomechanical force based on the anatomy of the human tooth structure. The new approach enables a single archwire to replace a conventional treatment progression of distinct monolithic archwires where stiffness increases with wire diameter to target larger tooth structures.

Previous work has shown a numerical modelling approach used to determine the target force for each tooth as a function of the periodontal ligature root support.  Further modeling of the orthodontic bracket and archwire system was compared to experimental mechanical testing. In this work, a correlation between the local transformation temperatures and the pseudoelastic stiffness is derived for each interbracket region in the dental arch.  Thermal analysis was performed on individual segments of processed wire. Mechanical simulations of the orthodontic treatment were performed using a three-bracket setup and compared with three-point bend tests and tensile tests. The results show that the full range of forces required for the initial stage of orthodontic treatment can be delivered by a single archwire that has been programmed to match the biomechanics of the tooth.