Abstract: An arch wire of T-shape cross section in the gingival occlusal transverse plane so as to have a labial lingual extending foot and a gingival occlusal extending crossbar is operative with a bracket having a mesial distal extending arch wire slot. The crossbar is urged against the bracket body by a ligature, usually an elastic ligation loop, until its lingual surfaces, which preferably are flat and coplanar, are in full butting engagement with the slot bordering portions of the bracket labial surface, which preferably are also flat and coplanar. At this time the foot is fully inserted in the slot and the optimum relative position and attitude of the bracket and the wire is determined for both tipping and rotation by this butting engagement. The function of the foot is primarily to guide the wire into this engagement and it can therefore fit with good clearance in the slot.

Abstract: A new multi-strand orthodontic arch wire comprises a plurality of wire strands of superelastic shape recovery metal alloy wrapped helically parallel to one another along the length of the wire, the ratio of the longitudinal pitch P of the wire to the external diameter D of the wire being between six and twelve. Such a wire is able to slide more freely in the bracket slots, and is less likely to breakage, than the short pitch wires previously used. A wire with a hollow central core, can also operate as a compression spring by frictionally engaging it with adjacent orthodontic elements, such as brackets, and arranging that its strands are spread radially apart from a neutral configuration, or it can operate as a traction spring by arranging that its strands are closed radially inward from a neutral configuration, the spring action being produced by the urge of the strands to return to the neutral configuration. Cored wires can act as a compression spring, but not as a traction spring.

Abstract: A new orthodontic bracket has a mesial-distal extending labially-open arch wire slot that in gingival-occlusal cross section is curved at its lingual face about a mesial distal axis and has its gingival and occlusial faces which usually are straight smoothly joining the lingual face and extending away from one another to form a slot opening of greater gingival-occlusial dimension. A spring retainer member embraces the gingival, occlusial and labial faces and is movable between a slot open position and a slot closed position, in the latter of which it opposes any protrusion of an arch wire out of the slot caused by misalignment between the slot and the arch wire The retainer is held in the slot closed position by latches which permit a small movement of the retainer away from the fully slot closed position, but which oppose such movement by spring and cam action.

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.