D Raboud | PubMed Health

PubMed2001

Three-dimensional force systems from vertically activated orthodontic loops.

When both vertical alignment and first-order rotation of teeth are to occur simultaneously, a 3-dimensional force system is required. This numerical study evaluated several appliances (rectangular loops and L-loops) used to vertically align teeth. Consideration was given to how these designs might be modified to produce the appropriate force system to allow both movements to occur simultaneously. It was found that the rectangular loop was the most appropriate choice for first-order corrections. For the rectangular loops studied, the in-plane force system was shown to be essentially independent of the out-of-plane effects, which allowed the 2 corrections to be controlled separately.

Algorithms↗

PubMed1998

Simulation of the superelastic response of SMA orthodontic wires.

Shape-memory alloys have properties that make them well suited to a variety of applications. One application for which their unique combination of properties (large elastic range, low modulus of elasticity, ability to deliver nearly constant forces over a wide range of deformations) seems ideally suited is for orthodontic retraction appliances where these properties are very desirable. The mechanical response of shape-memory alloys is modeled by a simple constitutive model that captures the essential superelastic behavior of the shape-memory wires. An initial value approach that iteratively converges to the appropriate boundary conditions is utilized to deliver numerical solutions. Qualitative agreement is shown with previous experimental works. The possible benefits of using such wires in an orthodontic retraction appliance are then investigated.

Biomechanical Phenomena↗