WO2010105059A1

WO2010105059A1 - Molar orthodontic bracket with hook plier stop

Info

Publication number: WO2010105059A1
Application number: PCT/US2010/026987
Authority: WO
Inventors: Paul E. Lewis; Dwight P. Schnaitter
Original assignee: Ultradent Products Inc
Current assignee: Ultradent Products Inc
Priority date: 2009-03-13
Filing date: 2010-03-11
Publication date: 2010-09-16
Anticipated expiration: 2011-09-13

Abstract

Molar orthodontic brackets (100) comprising a bracket base (102), an arch wire hole or tube (114), a plurality of tie wings (116), and a curved gingival hook (120) near a mesial end of the bracket (100). The curved hook (120) includes a proximal end (118) attached to one of the tie wings (116') and a curved shank (122) that extends away from the hook attachment tie wing (116'), curving towards the distal end of the bracket base (102). The bracket (100) advantageously includes a raised plier stop (124) disposed at a junction between the hook attachment tie wing (116') and the curved hook (120). The raised plier stop (124) extends laterally beyond an outer surface of the curved hook (120) so as to define a bending location where pliers gripping the curved hook (120) can abut against during intraoral bending of the hook (120). Inclusion of the raised plier stop (124) provides a tactile response to the practitioner, indicating that the correct bending location has been reached.

Description

MOLAR ORTHODONTIC BRACKET WITH HOOK PLIER STOP

BACKGROUND OF THE INVENTION

1. The Field of the Invention

The present invention relates to orthodontic brackets, particularly molar orthodontic brackets.

2. The Relevant Technology

Orthodontics is a specialized field of dentistry that involves the application of mechanical forces to urge poorly positioned or crooked teeth into correct alignment and orientation. Orthodontic procedures can be used for cosmetic enhancement of teeth, as well as medically necessary movement of teeth to correct underbites or overbites. For example, orthodontic treatment can improve the patient's occlusion and/or enhanced spatial matching of corresponding teeth.

The most common form of orthodontic treatment involves the use of orthodontic brackets and wires, which together are commonly referred to as "braces." Orthodontic brackets are small slotted bodies configured for direct attachment to the patient's teeth or, alternatively, for attachment to bands which are, in turn, cemented or otherwise secured around the teeth. Once the brackets are affixed to the patient's teeth, such as by means of glue or cement, a curved arch wire is inserted into the bracket slots. The arch wire acts as a template or track to guide movement of the teeth into proper alignment. End sections of the arch wire are typically captured within tiny appliances known as tube brackets or terminal brackets, which are affixed to the patient's bicuspids and/or molars. The remaining brackets typically include open arch wire slots and apply orthodontic forces by means of ligatures attached to the brackets and arch wire (e.g., by means of tie wings on the brackets). Molar tube brackets often include a curved hook extending from the gingival side of the bracket on which the practitioner can attach an elastic. Such hooks are bent intraorally by the practitioner in a labial or lingual direction to provide the desired orientation. Such intraoral bending of the hook can often result in debonding of the bracket from the tooth, greatly complicating the procedure. BRIEF SUMMARY OF THE INVENTION

The present invention is directed to a molar orthodontic bracket comprising a bracket base, an arch wire hole formed through the base, and a curved hook near a mesial or distal end of the bracket. The curved hook includes a proximal end attached to the bracket base and a curved shank that extends away from the hook attachment location, curving towards the opposite end of the bracket base. The bracket further includes a raised plier stop disposed at a junction between the hook attachment location and the curved hook. The raised plier stop extends laterally beyond an outer surface of the curved hook so as to define a bending location where pliers gripping the curved hook stop during intraoral bending of the hook. Inclusion of the raised plier stop provides a tactile response or feel to the practitioner, indicating that the correct bending location has been found.

Preferably, the molar bracket includes a plurality of tie wings, and the curved hook is located on a gingival side, near a mesial end of the base. The curved hook includes a proximal end attached to one of the tie wings and a curved shank that extends away from the hook attachment tie wing, curving towards the distal end of the bracket base. The bracket further includes a raised plier stop disposed at a junction between the hook attachment tie wing and the curved hook. The raised plier stop extends laterally beyond an outer surface of the curved hook so as to define a bending location where pliers gripping the curved hook stop during intraoral bending of the hook. Inclusion of the raised plier stop provides a tactile response or feel to the practitioner, indicating that the correct bending location has been found.

In one embodiment, the cross-sectional thickness of the curved hook to be bent is advantageously reduced at the bending location where the pliers grip. Such a reduced cross-section further facilitates bending of the hook at the prescribed bending location. In addition, because the thickness is thinned at the bending location, this further reduces or eliminates any tendency of the bracket to otherwise be debonded from the tooth during intra-oral bending.

These and other advantages and features of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

To further clarify the above and other advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

Figure IA is a perspective view of an exemplary molar orthodontic tube bracket according to the present invention; Figure IB is a perspective view of an alternative exemplary molar orthodontic bracket according to the present invention;

Figure 2 is a cross-sectional view through the bracket of Figure IA;

Figure 3 A is a perspective view of the bracket of Figure IA bonded to a molar of a patient; Figure 3B is a perspective view of the bracket of Figure 3 A in which a pair of pliers is being positioned for bending of the curved gingival hook;

Figure 3 C is a cross-sectional view of the bracket of Figure 3 B illustrating how the pliers abut against the stop of the bracket;

Figure 3D is a perspective view of the bracket of Figure 3B once the curved gingival hook has been bent lingually; and

Figure 3E is a perspective view of the bracket of Figure 3D once an elastic has been engaged within the hook.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS I. Introduction

The present invention is directed to a molar orthodontic bracket comprising a bracket base, an arch wire hole, and a curved hook near a mesial or distal end of the bracket. The curved hook includes a proximal end attached to the bracket body and a curved shank that extends away from the hook attachment location, curving towards the opposite end of the bracket base. The bracket advantageously includes a raised plier stop disposed at a junction between the hook attachment location and the curved hook. The raised plier stop extends laterally beyond an outer surface of the curved hook so as to define a bending location where pliers gripping the curved hook can abut against during intraoral bending of the hook. Inclusion of the raised plier stop provides a tactile response or feel to the practitioner, indicating that the correct bending location has been reached. II. Exemplary Brackets Incorporating a Curved Gingival Hook and Plier Stop

Figure IA illustrates an exemplary molar orthodontic tube bracket 100 comprising a bracket base 102 extending between mesial end 104 and distal end 106. Base 102 further includes an occlusal side 108 and a gingival side 110. A bonding pad 112 is attached to the lingual surface of bracket base 102. An arch wire hole or tube 114 extends mesially-distally through bracket base 102, and a plurality of tie wings 116 are formed on bracket base 102.

The illustrated embodiment includes four tie wings 116, two of which area on occlusal side 108, and two of which are on gingival side 110. The mesial gingival tie wing 116' serves as a hook attachment tie wing, such that a proximal end 118 of curved gingival hook 120 is attached to hook attachment tie wing 116'. Proximal end 118 extends gingivally away from tie wing 116', transitioning to curved shank 122, which curves towards the distal end 106 of bracket base 102. The preferred configuration is shown. It may also be possible to provide an alternative embodiment in which the curved hook 120 is disposed occlusally and/or is attached near the distal end 106 of the bracket base 102 so that the curved hook extends towards the mesial end 104 of base 102.

As further seen in Figure IA, curved hook 120 is curved sufficiently so that shank 122 forms an angle with the proximal end 1 18 of the curved hook 120 that is about 90° in the illustrated embodiment. Although a hook curvature of about 90° is preferred, the shank 122 of the curved hook 120 may typically form an angle with the proximal end 118 that is between about 45° and about 135°, preferably between about 80° and about 100°, and more preferably about 90°.

Bracket 100 advantageously includes a raised plier stop 124 disposed at a junction between hook attachment tie wing 116' and curved hook 120. Raised plier stop 124 extends laterally beyond an outer surface of curved gingival hook 120 and defines a location where pliers gripping curved hook 120 abut the stop 124 during bending of curved hook 120. Abutment of the pliers at stop 124 forces the bend to occur at or near the location of the stop 124, rather than elsewhere along the length of curved hook 120. For example, in one embodiment, the cross-sectional thickness of curved hook 120 is reduced at this bending location adjacent stop 124, which facilitates bending of the curved hook 120 while minimizing or eliminating the tendency of the bracket 100 to debond from the tooth during intraoral bending of the hook 120.

In Figure IA, raised plier stop 124 is disposed so as to extend beyond the buccal surface 126 of the curved hook 120. Although the stop member 124 may often be obscured from the practitioner's view as a result of its intraoral location at the back of the mouth (i.e. , on a molar, adjacent the inside of the patient's cheek), disposition of plier stop 124 along the buccal surface 126 of the bracket 100 may be preferred as it may provide somewhat better visibility of the stop 124.

Figure IB illustrates an alternative embodiment in which the raised plier stop is disposed on an opposite lingual surface 128, so that the plier stop 124 extends lingually beyond a lingual surface 128 of the curved hook 120. Nevertheless, buccal placement of the raised plier stop 124 may be further preferred over lingual placement, as lingual placement may interfere with engagement by a ligature with hook attachment tie wing 1 16'. Raised plier stop 124 as seen in Figure IA is shown closer up and in greater detail in the cross-sectional view of Figure 2. As seen in Figure 2, the cross-sectional thickness of curved hook 120 can be reduced through bending location B adjacent stop 124 as compared to the adjacent thickness of tie wing 1 16' and the curved shank 122 of hook 120. This thinning of the cross-sectional thickness at bending location B facilitates bending of the curved hook 120 while minimizing or eliminating the tendency of the bracket 100 to debond from the tooth during intraoral bending of the hook 120, as less force is required to bend hook 120 through thinned bending location B as compared to adjacent locations having greater thickness.

As seen in Figure 2, raised plier stop 124 may be in the shape of an inclined ramp where the ramped surface 130 is oriented towards hole 1 14, while stop surface 132 of raised plier stop 124 is disposed at an end of ramped surface 130, oriented away from hole 114. Stop surface 132 forms an angle with the buccal surface 126 of curved hook 120 and is of sufficient height to provide the practitioner with a tactile response when placing a pair of pliers against the stop surface 132. For example, the angle between stop surface 132 and buccal surface 126 is between about 45° and about 135°, more preferably between about 80° and about 100°, and most preferably about 90° (i.e., preferably the stop surface 132 is substantially perpendicular to buccal surface 126).

In addition, stop surface 132 preferably extends beyond buccal surface 126 between about 0.03 mm and about 0.5 mm, more preferably between about 0.05 mm and about 0.15 mm, and most preferably between about 0.07 mm and about 0.13 mm. In the illustrated embodiment in which raised plier stop 124 comprises a ramped surface 130, the ramp surface may typically be inclined between about 3° and about 25°, more preferably between about 10° and about 20° (e.g., about 15°). Of course, greater inclines (e.g., up to 90°) are possible, although the more shallow inclines are preferred, as a sharp incline (particularly a perpendicular or nearly perpendicular surface) may confuse the practitioner because such a surface may mimic the tactile feel provided by the stop surface of the raised plier stop.

Figures 3A-3E illustrate an exemplary method of using inventive brackets as disclosed herein. Figure 3 A shows a bracket 100 bonded to a first molar 150. As seen in Figure 3B, a pair of pliers 152 is being maneuvered between the buccal inside cheek of the patient and the bracket 100 so as to grip the curved hook 120. Figure 3C shows a cross-sectional view in which the pliers 152 are in gripping contact with curved hook 120, with the pliers 152 abutting against stop surface 132 of raised plier stop 124. Even though the practitioner may have difficulty visually evaluating the location of the pliers 152 relative to hook 120, because of the tactile response provided as pliers 152 abut stop surface 132 of raised plier stop 124, the practitioner can detect that the pliers 152 are correctly located for bending curved hook 120 at the prescribed location. Debonding of the bracket 100 as a result of bending is minimized or eliminated.

As seen in Figure 3D, the pliers 152 have been used to bend curved gingival hook 120 lingually, away from the buccal inside cheek surface of the patient. As seen in Figure 3E, an elastic ligature 154 engages curved hook 120 (e.g., for attachment to a corresponding hook of a canine bracket).

The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope. What is claimed is:

Claims

1. A molar orthodontic bracket comprising: a bracket base including mesial and distal ends and occlusal and gingival sides; a hole extending mesially-distally through the bracket base; a curved hook having a proximal end attached at a hook attachment location near the mesial or distal end of the bracket base, the curved hook including a curved shank extending away from the hook attachment location and curving toward the opposite end of the bracket base; and a raised plier stop disposed at a junction between the hook attachment location and the curved hook, the raised plier stop extending laterally beyond an outer surface of the curved hook so as to define a location where pliers gripping the curved hook stop during bending of the hook to facilitate bending of the hook at a prescribed location.

2. A molar orthodontic bracket comprising: a bracket base including mesial and distal ends and occlusal and gingival sides; a hole extending mesially-distally through the bracket base; a plurality of tie wings, one of which is a hook attachment wing disposed near the mesial end of the bracket base and which extends gingivally away from the hole; a curved hook having a proximal end attached to the hook attachment wing and a curved shank extending away from the hook attachment wing and curving toward the distal end of the bracket base; and a raised plier stop disposed at a junction between the hook attachment wing and the curved hook, the raised plier stop extending laterally beyond an outer surface of the curved hook so as to define a location where pliers gripping the curved hook stop during bending of the hook to facilitate bending of the hook at a prescribed location.

3. An orthodontic bracket as recited in claim 2, wherein the raised plier stop extends laterally beyond a buccal surface of the curved hook.

4. An orthodontic bracket as recited in claim 2, wherein the raised plier stop extends laterally beyond a lingual surface of the curved hook. An orthodontic bracket as recited in claim 2, wherein the curved hook has a reduced cross-sectional thickness at or near the location where pliers gripping the curved hook stop so as to facilitate bending of the hook at the location having the reduced cross- sectional thickness, reducing a tendency of the bracket to debond during intraoral bending.

5. An orthodontic bracket as recited in claim 2, wherein the shank of the curved hook forms an angle with the proximal end of the curved hook between about 45° and about 135°.

6. An orthodontic bracket as recited in claim 2, wherein the shank of the curved hook forms an angle with the proximal end of the curved hook between about 80° and about 100°.

7. An orthodontic bracket as recited in claim 2, wherein the shank of the curved hook forms an angle with the proximal end of the curved hook that is about 90°.

8. An orthodontic bracket as recited in claim 2, wherein the raised plier stop extends laterally beyond an outer surface of the curved hook between about 0.03 mm and about 0.5 mm.

9. An orthodontic bracket as recited in claim 2, wherein the raised plier stop extends laterally beyond an outer surface of the curved hook between about 0.05 mm and about 0.15 mm.

10. An orthodontic bracket as recited in claim 2, wherein the raised plier stop extends laterally beyond an outer surface of the curved hook between about 0.07 mm and about 0.13 mm.

11. An orthodontic bracket as recited in claim 2, wherein the raised plier stop is in the shape of a ramp comprising a ramped surface oriented towards the hole and a stop surface at an end of the ramped surface oriented away from the hole, the stop surface forming an angle with the outer surface of the curved hook that is between about 45° and about 135°.

12. An orthodontic bracket as recited in claim 2, wherein the raised plier stop is in the shape of a ramp comprising a ramped surface oriented towards the hole and a stop surface at an end of the ramped surface oriented away from the hole, the stop surface forming an angle with the outer surface of the curved hook that is between about 80° and about 100°.

13. An orthodontic bracket as recited in claim 2, wherein the raised plier stop is in the shape of a ramp comprising a ramped surface oriented towards the hole and a stop surface at an end of the ramped surface that is substantially perpendicular to the outer surface of the curved hook.

14. An orthodontic bracket as recited in claim 14, wherein the ramped surface is inclined at an angle between about 3° and about 25°.

15. An orthodontic bracket as recited in claim 15, wherein the ramped surface is inclined at an angle between about 10° and about 20°.

16. An orthodontic bracket as recited in claim 14, wherein the ramped surface is inclined at an angle of about 15°.

17. A molar orthodontic tube bracket comprising: a bracket base including mesial and distal ends and occlusal and gingival sides; a hole extending mesially-distally through the bracket base; a plurality of tie wings, one of which is a hook attachment wing disposed near the mesial end of the bracket base and which extends gingivally away from the hole; a curved hook having a proximal end attached to the hook attachment wing and a curved shank extending away from the hook attachment wing and curving toward the distal end of the bracket base; and a raised plier stop disposed at a junction between the hook attachment wing and the curved hook, the raised plier stop extending laterally beyond an outer buccal surface of the curved hook so as to define a bending location where pliers gripping the curved hook stop during intraoral bending of the hook, the bending location of the curved hook having a cross-sectional thickness that is reduced relative to adjacent portions of the hook so as to facilitate bending of the hook at the reduced cross-sectional thickness of the bending location, reducing a tendency of the bracket to debond during intraoral bending.

18. An orthodontic bracket as recited in claim 18, wherein the raised plier stop extends laterally beyond the outer buccal surface of the curved hook between about 0.07 mm and about 0.13 mm.

19. An orthodontic bracket as recited in claim 18, wherein the raised plier stop is in the shape of a ramp comprising a ramped surface oriented towards the hole and a stop surface at an end of the ramped surface oriented away from the hole, the stop surface forming an angle with the outer buccal surface of the curved hook that is between about 80° and about 100°.

20. An orthodontic bracket as recited in claim 18, wherein the raised plier stop is in the shape of a ramp comprising a ramped surface oriented towards the hole and a stop surface at an end of the ramped surface that is substantially perpendicular to the outer buccal surface of the curved hook.