Claims:
What I claim is
1. An orthodontic assembly comprising, in combination:
2. The invention as defined by claim 1, which when uprighting or torquing movements are required provides for the combination therewith of an auxiliary lever principle.
3. The invention according to claim 2, wherein the forces applied to the tooth are easy to apply and measure and the center of rotation is closer to the incisal edge of such tooth.
4. The invention according to claim 3, which provides accommodation in selected positions of a separate spring for each tooth to obtain root movement.
Description:
This invention relates to an assembly of orthodontic elements.
Maloccluded teeth are straightened by tying an arch wire to the teeth by means of bands connected to appropriate teeth, each band having a bracket for reception of the arch wire.
The principal object of the invention is to provide a novel assembly of orthodontic elements providing for the attachment of the arch wire to the teeth at different levels on the crown of a tooth as treatment proceeds.
According to this invention a ribbon arch bracket is employed having side slots or housings for the arch wire, one near the top, the other near the bottom, so that the arch wire lengths may be located in either slot at will. In addition a hole or through passage is provided through which an arm or axle of a wire spring may pass and be retained.
The said spring is a helical torsion spring having a short arm or axle, two or more closely turned coils and a long lever arm, the arrangement providing that the axle may be supported in the bracket while the lever arm lies against the tooth.
The bracket is connected as by spot-welding to a band with the narrower slot in the bracket presented near the gingival location of the tooth.
The complete assembly therefore comprises a bracket attached to a band with spaced apart slots or housings in the bracket, an intermediate hole through the bracket, an arch wire in one or other of the slots or housings, and when required, a helical torsion spring secured in the intermediate hole with the long lever arm exerting pressure against a tooth so as to move it about its axis of rotation.
A clear understanding of the invention may be arrived at from a consideration of the accompanying drawings, wherein:
FIG. 1 is a plan view of a band and bracket on a tooth.
FIG. 2 is a plan view of the bracket and band.
FIG. 3 is a front view of the bracket.
FIG. 4 is a side view of the bracket.
FIG. 5 is a front view showing the spring.
In the arrangement illustrated, the assembly comprises a U-shaped arch bracket 5 attached to a band 6, by spot welding or other means, with an upper slot 7 in the sidewalls of the bracket arch itself near the incisal or occlusal surface of a tooth, and a lower slot 8 in such walls near the gingival end of the bracket.
Arch wire 12 is located in the slot 7 as well as in the slot 8.
There is also an intermediate transverse hole 9 through the bracket sidewall of the arch sidewalls for the reception of the horizontal shaft or axle of a helical torsion spring 10 having a vertical long lever arm 11 adapted to exert pressure on a tooth embraced by band 6, so as to move the tooth about its axis of rotation. The short arm 13 of the spring bears against the front of band 6.
With this invention the arch wire position of choice is such that if the practitioner desired, and during tooth movement, the center of rotation of the tooth may be located near the apex of the root, by locating the arch wire in a slot towards the gingival end of the bracket. Where uprighting of a tooth is required the arch wire may be located on a bracket at a point near the incisal or occlusal surface of a tooth.
In accordance with the invention the brackets employed allow the arch wire to be located in and changed at will in a number of different locations so as to impart more or less leverage on a tooth in desired directions so as to more efficiently accomplish orthodontic treatment of maloccluded teeth.
During the treatment of orthodontic patients using the technique known as the Begg Light Wire Technique, three serial stages of treatment are defined.
Accordingly, using the bracket hereinafterwards described, enables the incisor teeth to be moved distally in stage one without the apex of the teeth moving forward excessively.
As the roots of the teeth have to be moved distally in any event, this stage can be shortened considerably in accordance with this invention, by reducing to a minimum mesial apical root movement in stage one of treatment.
In stage three, when uprighting or torquing movements are desired, an auxiliary appliance us used whereby a lever principle is employed to move the roots. If the lever arm is long, the forces exerted at its end are lighter and therefore easier to apply and measure. Also, the center of rotation being closer to the incisal edge of a tooth means that maximum root movement occurs in a distal direction.
The bracket employed provides accommodation in selected positions, of an axled or separate spring for each tooth to obtain root movement.
This is advantageous in cases where all or some of the anterior teeth require uprighting, and enables the use of a spring which can be measured more easily then springs currently in use. The requirements of tooth movement of individual teeth may more efficiently be served because no other teeth are involved.