The present invention relates generally to the field of orthodontics and, more specifically, to the field of orthodontic bracket assemblies.
According to established orthodontic techniques, it is well known to attach an orthodontic bracket assembly to a patient's tooth. The bracket assembly provides a location for attaching an archwire and other orthodontic devices to facilitate movement of the tooth. According to established orthodontic techniques, it is well known to ligate an archwire to the orthodontic bracket assembly utilizing an elastic or metal ligature. In conventional orthodontic bracket assemblies, the ligature is wrapped around respective gingival and occlusal tie wings so as to overlay the archwire at mesial and distal ends of the orthodontic bracket assembly.
Recently, designers have created self-ligating bracket assemblies that do not require a separate ligature for attachment of the archwire to the bracket assembly. One type of self-ligating bracket assembly is supplied with a locking member that is movable between an open position, permitting access to the archwire slot, and a closed position, inhibiting access to the archwire slot. Self-ligating bracket assemblies substantially decrease the time involved in performing ligation procedures.
In one embodiment, a bracket assembly may generally include a base defining an archwire slot, a pivot member supported by the base, and a locking member supported by the pivot member for pivoting movement between a closed position, in which access to the archwire slot is inhibited, and an open position, in which access to the archwire slot is permitted. The locking member may include a looped base portion supporting the locking member on the pivot member. In some constructions, the bracket assembly may include a pivot limiting structure, such as a knob and slot, operable to limit pivoting movement of the locking member beyond an open position.
In another embodiment, the bracket assembly may include a locking member having a V-shaped latch portion extending between the mesial and distal ends of the locking member and engageable with the base to hold the locking member in the closed position. In some constructions, the locking member may include a lingual finger portion engageable with the archwire to provide active ligation.
In yet another embodiment, the bracket assembly may include a base defining an archwire slot and a V-shaped recess adjacent the archwire slot and extending substantially between the mesial and distal ends of the base. The recess may receive a V-shaped latch portion of the locking member. The base may include mesial and distal end walls closing the ends of the recess. The base may include overhanging portions engageable with the latch portion to positively lock the latch portion in the closed position.
In a further embodiment, the bracket assembly may include a base defining a relief area, and a locking member including a tab engageable to compress the latch portion and overlying the relief area. The relief area may enable manipulation of the tab.
Independent features and independent advantages of the present invention will become apparent to those skilled in the art upon review of the following detailed description and drawings.
Before at least one embodiment of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.
Although references are made below to directions, such as left, right, up, down, top, bottom, front, rear, forward, back, etc., in describing the drawings, they are made relative to the drawings (as normally viewed) for convenience These directions are not intended to be taken literally or limit the present invention in any form.
An orthodontic bracket assembly 10 embodying the invention is illustrated in
The base 14 defines gingival and occlusal directions and mesial and distal directions. The base 14 includes two gingival tie wings 26 extending from the base 14 in the gingival direction and two occlusal tie wings 28 (one shown) extending from the base 14 in the occlusal direction. Although dependent upon the position of the tooth to which the bracket assembly 10 is mounted, the illustrated tie wings 26, 28 can be further identified as mesial tie wings 30 located on the mesial side of the bracket assembly 10 and distal tie wings 32 (one shown) located on the distal side of the bracket assembly 10.
The base 14 also defines a latch-receiving recess 36 having a generally beveled or V-shape (when viewed from a side or ¾ view) and extending in a mesio-distal direction. In the illustrated construction, ends walls 40 close the mesial and distal ends of the recess 36. A dish-shaped retrusion or relief area 44 is defined in the cross-bar portion 46 of the gingival portion of the ceramic base 14 adjacent the recess 36. Locking edges or overhanging portions 48 are provided at the labial edge of the recess 36 and on the mesial and distal sides of the relief area 44.
In the illustrated ceramic base 14, the cross-bar portion 46 of the gingival portion of the base 14 may provide improved strength of the base 14. It should be understood that, if the base 14 is formed of another material, such as, for example, metal, a cross-bar portion may not be provided on the gingival portion of the metallic base 14 (see
The locking member 18 is supported on the base 14 for movement between a closed position (shown in
As shown in
The latch portion 60 is generally re-curved or V-shaped (when viewed from a side or ¾ view) and extends across the mesio-distal width of the locking member 18. The latch portion 60 is configured as a resilient or spring latch, so that the latch portion 60 will compress when forced into the recess 36. The spring force in the latch portion 60 and engagement with the overhanging portions 48 positively holds the locking member 18 in a closed position.
It should be understood that, in other constructions (not shown), the resilient characteristic of the latch portion 60 may be provided by another spring-type structure and/or by a resilient material portion (e.g., elastomeric or flexible material, plastic, rubber, etc.) provided on the locking member 18.
In the closed position, the latch portion 60 is positioned between the end walls 40. The end walls 40 substantially prevent entry of debris (e.g., food) into the V-shaped portion of the latch portion 60 and into the recess 36.
In the illustrated construction, the latch portion 60 extends across a substantial portion of the mesio-distal width of the base 14 and engages the base 14 at the mesial and distal ends. This may improve dental rotation corrections and may inhibit deformation and/or flaring out labially of the latch portion 60 (especially at the mesial and distal ends) and of the locking member 18.
For example, if the mesio-distal width of the base 14 is “1.00”, the mesio-distal width of the latch portion 60 is on the order of, for example, about 0.75 to about 0.95 and, preferably, may be about 0.88 the mesio-distal width of the base 14. In such constructions, the combined mesio-distal width of the end walls 40 is, for example, about 0.25 and, preferably, may be about 0.12 the mesio-distal width of the base 14. However, it should be understood that, if no end walls 40 are provided, the mesio-distal width of the latch portion 60 may be on the order of 1.00 the mesio-distal width of the base 14. It should also be understood that, for some other constructions (not shown), the latch portion 60 may be smaller than 0.75 the mesio-distal width of the base 14.
A tab 64 is provided on the latch portion 60. The tab 64 lies across a portion of the relief area 44 when the locking member 18 is in the closed position. The relief area 44 allows for easy insertion of a removal tool (similar to the tool 366 shown in
In the illustrated construction, the tab 64 extends less than amount of the latch portion 60 extends across the mesio-distal width of the base 14. For example, if the mesio-distal width of the base 14 is “1.00”, the mesio-distal width of the tab 64 may be approximately 0.50 or more and, preferably, may be approximately 0.50 the mesio-distal width of the base 14. However, it should be understood that, if no end walls 40 are provided, the mesio-distal width of the tab 64 may be approximately slightly more than 0.50 the mesio-distal width of the base 14. It should also be understood that, for some other constructions (not shown), the tab 64 may be smaller than 0.50 the mesio-distal width of the base 14.
It should be understood, that, in other constructions (not shown), a tab may not be provided on the latch portion 60. In such construction, the gingival end of the latch portion 60 may be directly engaged and manipulated by the removal tool.
The locking member 18 rotates about a pivot member or cylindrical rod 72, which may be secured to the base 14 (e.g., extending between the occlusal tie wings 28), but which may instead be secured to and rotate with the locking member 18. In the illustrated construction, the looped base portion 52 extends from the body portion 56, below and around the pivot rod 72. The base portion 52 thus captures the pivot rod 72 to pivotally support the locking member 18 on the pivot rod and on the base 14.
The illustrated arrangement of the looped base portion 52, the body portion 56 and the latch portion 60 provides for a larger, substantially flat and uninterrupted surface area on the body portion 56. The locking member 18 may have fewer angular edges to improve comfort (e.g., if the mesial and distal ends contact the lips and cheeks of a patient). Also, such a body portion 56 may have improved suitability for coating, laminating, etc. in a manner described in U.S. Patent Application Publication No. US 2004/0072119 A1, the entire contents of which is hereby incorporated by reference.
It should be understood that, in other constructions (not shown), the arrangement of the locking member 18 on the base 14 may be different. As an example, the pivot rod 72 may be supported on the gingival tie wings 26, and the latch portion 60 may resiliently engage the occlusal tie wings 28 (e.g., in a V-shaped latch-receiving recess 36 formed in the occlusal tie wings 28) to hold the locking member 18 in the closed position. Such an arrangement would generally be the inverse of the arrangement illustrated
In some constructions (as shown in
In the illustrated construction, the structure 76 includes a small vertically-opening notch or slot 82 formed in the looped base portion 52 and providing a first limit surface and a protrusion, projection or knob 86 connected to the pivot rod 72 and providing a second limit surface. The knob 86 engages the end of the slot 82 to hold the locking member 18 in the open position (as shown in
To open the locking member 18, the tab 64 is engaged to compress the latch portion 60 into the recess 36. The latch portion 60 is disengaged from the overhanging portions 48, and the locking member 18 is pivoted labially to the open position. In the illustrated construction, engagement of the knob 86 and the end of the slot 82 holds the locking member 18 in the open position. The archwire slot 22 is accessible to insert or remove the archwire 68.
To close the locking member 18, the locking member 18 is pivoted lingually with a human finger. As the latch portion 60 engages the base 14, the latch portion 60 compresses to clear the overhanging portions 48. The latch portion 60 then expands and is engaged lingually behind the overhanging portions 48 such that the locking member 18 is locked in the closed position (shown in
In some constructions, a ramp portion (not shown) may be provided on the labial surface of the base 14. Engagement, in the direction of closing, of the latch portion 60 against such a ramp portion may cause the latch portion 60 to be compressed to clear the overhanging portions 48 such that the locking member 18 is more easily moved to the closed position without the use of the tool. In yet other constructions (not shown), a tool may be used to assist in moving the locking member 18 to the closed position.
In the illustrated construction, a recessed area or generally Y-shaped bevel 90 is provided on the labial surface of the occlusal tie wings 28 of the base 14. As shown in
The orthodontic bracket assembly 110 of
A wall 138 is provided between the V-shaped (when viewed from a side or ¾ view) recess 136 and the archwire slot 122. The recess 136 houses the V-shaped latch portion 160, and, during compression and/or extension of the latch member 160, the wall 138 keeps latch portion 160 out of archwire slot 122 such that the latch portion 160 does not engage or obstruct the archwire 168.
The occlusal tie wings 128 include a semi-circular recess 170 on the lingual side. The recess 170 is sized to receive a pivot rod 172 on which a locking member 118 may rotate between a closed position and an open position. The locking member 118 includes a looped base portion 152, a body portion 156, and a V-shaped (when viewed from a side or ¾ view) latch portion 160. As described in previous embodiments, the base portion 152 is configured to retain the locking member 118 on the pivot rod 172.
The V-shaped latch portion 160 is received in V-shaped recess 136 when the locking member 118 is in the closed position. A tab 164 extends from the latch portion 160 and may lie in a vertically-extending relief area 144 in the base 114 when closed. In the illustrated construction, the relief area 144 provides increased space above and behind the tab 164 such that the latch portion 160 can easily compress down and out away from overhanging portions 148. The tab 164 may be used to compress the latch portion 160 and unlock the locking member 118 (as shown in
In the construction illustrated in
As best shown in
The embodiment of
As shown in
As shown in
In the illustrated construction, the cross-bar portion 246 extends over the relief area 244 and over the tab 264 when the locking member 218 is in the closed position. Also, in the illustrated construction, tab 264 is lingually inset under cross-bar 246. This arrangement prevents unwanted or accidental engagement of the tab 264 (e.g., by a finger, toothbrush, etc.) and opening of the locking member 218, prevents engagement with the lips or cheeks of the patient, etc. The cross-bar portion 246 may also prevent debris (e.g., food) from entering relief area 244.
The embodiment of
In the illustrated construction, the locking member 318 is also wider and includes a wider latch member 360 received in the recess 336. In the illustrated construction, the latch portion 360 extends across substantially all of the mesio-distal width of the base 314 and engages the base 314 at the mesial and distal ends. This may further improve dental rotation corrections using a large moment of couple and may inhibit deformation and/or flaring out labially of the latch portion 360 (especially at the mesial and distal ends) and of the locking member 318.
For example, because no end walls 40 are provided, the mesio-distal width of the latch portion 360 is on the order of 1.00 the mesio-distal width of the base 314. However, it should be understood that the mesio-distal width of the latch portion 360 may be less than (e.g., about 0.75 to about 0.95 and may be about 0.88) the mesio-distal width of the base 314, for example, if a locking member (similar to the locking member 18, 118 or 218) is used with the base 314. It should also be understood that, for some other constructions (not shown), the latch portion 360 may be smaller than 0.75 the mesio-distal width of the base 314.
In the illustrated construction, the slot liner 324 lines the archwire slot 322 and at least a portion of recess 336. The slot liner 324 may be formed of a material with improved characteristics relative to a ceramic base 314 to resist wear or damage from engagement with the latch portion 360. It should be understood that, in other constructions (not shown), the slot liner 324 may not line any region of the recess 336.
One or more independent features or independent advantages may be set forth in the following claims: