Dentistry – Orthodontics – Bracket
Reexamination Certificate
2000-10-19
2002-11-12
O'Connor, Cary E. (Department: 3732)
Dentistry
Orthodontics
Bracket
C433S010000, C433S013000
Reexamination Certificate
active
06478579
ABSTRACT:
FIELD OF THE INVENTION
The present invention is directed to an orthodontic twin bracket, and in particular an orthodontic twin bracket which includes protrusions on the floor and side walls of the archwire slot in order to reduce friction.
BACKGROUND OF THE INVENTION
Various methods are presently in use for correcting the orientation of irregular teeth. It is generally accepted that each tooth has a particular location in the arch and a preferred angle between its long axis and the occlusal plane. In the mouth, the tooth long axis can best be approximated by visualizing the long axis of the crown, the only visual component of the tooth. Therefore, the preferred angle referred to above can be more practically defined as the normal angle between the crown long axis of a particular tooth and the occlusal plane.
In orthodontics, an archwire is used to apply unidirectional and torquing forces to the irregular teeth. The archwire is attached to the teeth by means of a bracket assembly. Preferably, a bracket assembly is bonded directly to the facial surface of the tooth. In one embodiment of such an assembly, the tie wings are affixed to a bonding pad which is then adhered to the tooth.
Alignment of the bracket is critical. With the development of better adhesives to bond orthodontic brackets to a tooth, the sizes of the orthodontic brackets have become smaller and smaller over the years. As a consequence, and because present day adhesives have a tendency to dry rapidly, the amount of time an orthodontist has to place an orthodontic bracket on a patient's tooth, before the adhesive dries, can be reduced to a matter of seconds. Coupled with the small size of the orthodontic bracket itself, orthodontists have routinely sought new bracket designs to facilitate easy, quick and accurate alignment of orthodontic brackets on the tooth. As mentioned earlier, the occlusal plane and the tooth long axis are two reference lines which the orthodontist uses in mounting a bracket to the tooth. Orthodontists have sought bracket designs and methods which help align the archwire slot with the occlusal plane of the patient's teeth and the bracket with the tooth long axis.
Another problem encountered with small brackets is identification. Because the orthodontist typically has different brackets for different teeth, it is important and that the orthodontist be able to easily distinguish the different brackets in order to adhere the appropriate bracket to the proper tooth.
As the forces applied by the bracket and archwire move the teeth toward their correct positions, the bracket slides relative to the archwire. Therefore, it is important that the frictional forces between the archwire slot and the archwire are minimized to allow relative movement therebetween.
It is well-known that one is able to ligate an archwire to an orthodontic bracket using an elastic, elastomeric or metal ligature. In a twin edgewise orthodontic bracket, the ligature is stretched around respective undercuts of gingival and occlusal tie wings so as to overlay the archwire at mesial and distal ends of the orthodontic bracket. Orthodontists have sought the ability to increase the options available in ligating an archwire to a bracket.
Another important consideration in the design of a bracket is the structural integrity of the bracket. Due to its small size and the concentration of forces relative to the archwire slot, it is critical that the bracket is designed to withstand forces applied to it without failure.
It would be desirable to have a bracket design which reduces friction between the archwire and the archwire slot. It would be desirable to have a bracket design which permits easy, quick and accurate alignment with the crown long axis and with the occlusal plane. It would be desirable to have a bracket which is easy to identify. It would be desirable to have a bracket design which supports multiple ligation options. It would be desirable to have a bracket which is both small in size and structurally sound. It would be extremely advantageous to have a bracket design which incorporates all of the above features of reduced friction, accurate alignment, ease of identification, multiple ligation options, small size and structural integrity.
SUMMARY OF THE INVENTION
In accordance with one embodiment of the present invention, an orthodontic twin bracket is provided which includes: an occlusal tie wing having a mesial wing tip and a distal wing tip; a gingival tie wing having a mesial wing tip and a distal wing tip; and an archwire slot having an archwire floor and having two archwire side walls. The archwire slot further includes: at least one protrusion extending buccally from the archwire floor; two protrusions extending occlusally from a gingival side wall and having a gingivally-extending depression located between the two protrusions; and two protrusions extending gingivally from an occlusal side wall and having an occlusally-extending depression located between the two protrusions. The bracket also includes a base portion having a backside for attachment to a tooth.
Preferably, the orthodontic bracket further includes a hook extending from one of the wing tips.
Preferably, the hook is integrally formed into the bracket.
Preferably, the hook is capable of bending in two without breaking.
Preferably, the orthodontic bracket further includes a vertical slot with an opening in the base portion.
Preferably, the vertical slot is about 0.02 inches by 0.02 inches in cross-section.
Preferably, the archwire floor includes at least two protrusions extending buccally from the archwire floor and having a labially-extending depression located between the two protrusions.
Preferably, the two most buccally-extending portions of the two protrusions in the archwire floor are substantially aligned with the two most occlusally-extending portions of the two protrusions in the gingival side wall and the two most gingivally-extending portions of the two protrusions in the occlusal side wall.
Preferably, the depression located between the two protrusions in the archwire floor is substantially aligned with the depression located between the two protrusions in the gingival side wall and the depression located between the two protrusions in the occlusal side wall.
Preferably, the orthodontic bracket also includes a labially-extending saddle located between the two wing tips of the occlusal tie wing and a labially-extending saddle located between the two wing tips of the gingival tie wing.
Preferably, the orthodontic bracket also includes indicia formed in at least one of the wing tips.
Preferably, the bracket is a twin bracket and the side wall and floor protrusions are rounded.
Preferably, the bracket provides for reduced friction between the archwire slot and the archwire for better sliding mechanics.
Preferably, the bracket provides for increased archwire efficiency.
Preferably, during a phase of the orthodontic treatment in which out-of-alignment teeth are moved back into alignment, the orthodontic bracket provides improved continuous leveling force.
Preferably, the orthodontic bracket provides reduced binding between the archwire and bracket.
In one embodiment, the orthodontic twin bracket includes: (a) an occlusal tie wing having a mesial wing tip and a distal wing tip and a labially-extending saddle located between the mesial wing tip and the distal wing tip; (b) a gingival tie wing having a mesial wing tip and a distal wing tip and a labially-extending saddle located between the mesial wing tip and the distal wing tip; (c) an archwire slot having an archwire floor and having two archwire side walls, and further including: (i) at least one protrusion extending buccally from the archwire floor; (ii) two protrusions extending occlusally from a gingival side wall and having a gingivally-extending depression located between the two protrusions; and (iii) two protrusions extending gingivally from an occlusal side wall and having an occlusally-extending depression located between the two protrusions; the depression located between the two p
O'Connor Cary E.
RMO, Inc.
Sheridan & Ross P.C.
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