Force system developed by V bends in an elastic orthodontic wire.

The force system generated by a simple V bend in a straight wire was studied by means of the principles for small deflection of a beam and a model developed for the description of the forces and moments. The relationship between the size of the bend and the interbracket position on the force system developed is analyzed and discussed in relation to clinical problems. The parallel between positioning of a V bend and the "geometries" developed between a straight wire and angulated brackets is drawn. Four principally different force systems could be developed by the V bend and a method for the predetermination of the force systems is provided. The general principles are exemplified for wires with different moduli of elasticity, varying materials, and cross-sectional dimensions. Stainless steel and beta titanium (TMA) wires in dimensions of 0.16 inch and 0.017 x 0.025 inch are given as examples.