Elastomeric orthodontic traction ribbon springs

Abstract

An elastomeric traction ribbon spring for use in orthodontic procedures consists of a thin and narrow ribbon of substantially constant thickness and width along the length of its operative portion, which is provided with a centrally disposed row of relatively small relatively closely spaced holes extending through its thickness dimension. The tension applied between two anchor points is adjusted by choice of the holes engaged at these points. A specific example is 0.9 mm (0.035in) wide and 0.3 mm (0.012in) thick with holes of 0.2 mm (0.008in) diameter spaced 0.58 mm (0.023in) apart center to center. Each hole may have at the underface a funnel-shaped recess that facilitates mounting of the ribbon on its anchor point; a method of forming such holes is provided using an apertured die and a concentric pointed punch. The spring may be supplied in a long length from which the required amount is cut. Alternately they may be in separate lengths each with a finger-gripping part at one end; the distal end may be provided with a larger hole to facilitate attachment to the distal anchor point, while the mesial end may have a hole for temporary attachment of a tension meter. A particularly suitable anchor is a post with an enlarged head, the ribbon being forced over the head, which may be ball- or mushroom-shaped. A tool with a cup-shaped head is provided to facilitate forcing the ribbon over the enlarged head when it is inaccessible by hand.