WO2010014299A1

WO2010014299A1 - Hand instrument for removing an orthodontic archwire from an orthodontic appliance

Info

Publication number: WO2010014299A1
Application number: PCT/US2009/047429
Authority: WO
Inventors: James D. Cleary
Original assignee: 3M Innovative Properties Company
Priority date: 2008-07-30
Filing date: 2009-06-16
Publication date: 2010-02-04

Abstract

An orthodontic hand instrument includes a pair of hooks for engaging an archwire that is received in an archwire slot of an orthodontic appliance. The hand instrument also includes a post having an outer end portion for contact with the appliance as the hooks urge the archwire out of the archwire slot. In certain embodiments, at least one of the hooks is movable toward the other hook as the post is advanced toward the appliance so that the hooks are positioned closely adjacent the appliance regardless of its overall width. In other embodiments, the hooks and the post are part of an assembly that is pivotally movable to enhance use of the hand instrument in various regions of the oral cavity.

Description

HAND INSTRUMENT FOR REMOVING AN ORTHODONTIC ARCHWIRE FROM AN ORTHODONTIC APPLIANCE

Background of the Invention

L Field of the Invention

This invention relates to a hand instrument for use by an orthodontic practitioner to remove an orthodontic archwire from the archwire slot of an orthodontic appliance such as a bracket.

2. Description of the Related Art

Orthodontic therapy is a specialized type of treatment within the field of dentistry, and involves of repositioning of malpositioned teeth to orthodontically correct locations. Orthodontic therapy often enhances the aesthetic appearance of the teeth, especially in instances when the patient's front teeth are malpositioned or crooked. Orthodontic treatment can also improve the patient's occlusion so that opposed teeth function better with each other during the times that the patient is chewing.

Many types of orthodontic treatment programs involve the use of a set of tiny appliances and archwires that are commonly known collectively as "braces". During such treatment programs, small appliances known as brackets are fixed to the patient's anterior, cuspid and bicuspid teeth, and an archwire is inserted into a slot of each bracket. The archwire forms a track to guide movement of the teeth to desired positions. End sections of the archwires are often captured in tiny appliances known as buccal tubes that are fixed to the patient's molar teeth.

Many orthodontic brackets have small wings known as "tiewings" that are connected to a body of the bracket. Once the bracket has been attached to a tooth and an archwire has been placed in the archwire slot of the bracket, a ligature is coupled to the bracket in order to retain the archwire in the archwire slot. One example of a commercially available orthodontic ligature is a small, elastomeric O-ring that is installed by stretching the O-ring along a path behind the tiewings and over the facial side of the archwire.

Other types of orthodontic appliances are known as self-ligating brackets, and are provided with a latch for coupling the archwire to the bracket. Use of the latch avoids the need to use a ligature to secure the archwire to the bracket. The latch may comprise a movable clip, spring member, sliding cover, shutter, bail or other structure that is connected to the bracket body for retaining the archwire in the archwire slot.

Examples of improved, self-ligating orthodontic appliances with clips are described in applicant's U.S. Patent Nos. 6,582,226, 7,140,876, and 7,217,125 and 1,311,111. The appliances described in those documents have one or more clips for retaining an archwire in the archwire slot, and the clips release the archwire from the archwire slot whenever the archwire exerts a force on the appliance that exceeds a certain minimum value. The minimum value is significantly less than the force required in the same direction to debond the appliance from the tooth, and consequently helps to ensure that the appliance will not spontaneously debond from the tooth during the course of treatment.

Another improved self-ligating appliance is described in applicant's co-pending U.S. Patent Application entitled "LOW PROFILE SELF-LIGATING ORTHODONTIC APPLIANCE WITH CLIP", Serial No. 61/084,691. The appliances described in that patent application are relatively small, a significant benefit when used on the lingual side of the patient's teeth. However, the relatively small size of the appliances tends to increase the difficulty in releasing the archwire from the clips of the appliances, especially in posterior regions of the oral cavity where access is limited.

U.S. Patent No. 6,582,226 describes hand instruments that are useful for releasing archwires from self-ligating appliances having clips. In general, the hand instruments described in that reference include a cam section that is adapted to bear against the appliance as the hand instrument is manipulated in order to urge the archwire in a direction toward the clips. By bearing against the appliance, the cam section helps to ensure that the appliance is not unintentionally debonded from the tooth as the archwire is pushed against the clips to open the same. Summary of the Invention

The present invention relates to improvements in orthodontic hand instruments that are useful for removing archwires from self-ligating orthodontic appliances. Certain aspects of the invention are directed to improvements that facilitate use of the hand instrument in conjunction with a variety of orthodontic appliances having overall, mesial- distal widths that differ from one another. Other aspects of the invention are directed toward a coupling of the hand instrument that enables a handle of the hand instrument to be adjusted to a convenient, comfortable orientation in accordance with the location of the appliance in the patient's oral cavity.

In more detail, one aspect of the present invention is directed to a hand instrument for removing an orthodontic archwire from an archwire slot of an orthodontic appliance. The hand instrument comprises a body and a pair of arms extending along opposite sides of the body. Each of the arms has an outer end portion with a hook. A post is connected to the body and is movable relative to the body. The post has an outer end portion extending between the hooks. The hand instrument also comprises a coupling connecting at least one of the arms to the body for enabling movement of at least one of the hooks in a direction toward the other hook as the post moves in a direction away from the body.

Another aspect of the present invention is also directed to a hand instrument for removing an orthodontic archwire from the archwire slot of an orthodontic appliance. The hand instrument comprises a handle and a lever pivotally connected to the handle. The hand instrument further comprises a body and a pair of arms extending along opposite sides of the body. Each of the arms has an outer end portion with a hook. An elongated post is connected to the body and has an outer end portion extending between the hooks. One of the post and the pair of arms (i.e., either the post or the pair of arms) is connected to the lever and is movable relative to the body as the lever is moved relative to the handle. The body is pivotally connected to the handle for movement of the body relative to the handle in an arc about the longitudinal axis of the post.

Another aspect of the present invention is directed toward a method for removing an orthodontic archwire from an archwire slot of an orthodontic appliance. The method comprises placing a pair of hooks along opposite sides of the appliance and in positions extending at least partially around the archwire, and moving a post along a path between the hooks toward a position for contact with the appliance. The method further comprises shifting at least one of the hooks in a direction toward the other hook and toward a position nearer to the appliance, and urging the post in a direction against the appliance while moving the hooks in a generally opposite direction in order to remove the archwire from the archwire slot of the appliance.

Further details of the invention are defined in the features of the claims.

Definitions

As used herein: "Mesial" means in a direction toward the center of the patient's curved dental arch.

"Distal" means in a direction away from the center of the patient's curved dental arch.

"Occlusal" means in a direction toward the outer tips of the patient's teeth.

"Gingival" means in a direction toward the patient's gums or gingiva. "Facial" means in a direction toward the patient's lips or cheeks.

"Lingual" means in a direction toward the patient's tongue.

Brief Description of the Drawings

Fig. 1 is a side elevational view of a hand instrument illustrated in accordance with one embodiment of the present invention;

Fig. IA is an enlarged fragmentary side elevational view of a front portion of the hand instrument that is designated by the dashed circular line in Fig. 1;

Fig. 2 is an enlarged side elevational view with parts broken away in section of a portion of the hand instrument illustrated in Fig. 1;

Fig. 3 is an enlarged front elevational view of the portion of the hand instrument that is shown in Fig. 2;

Fig. 4 is a fragmentary, enlarged, rear elevational view of a portion of the assembly shown in Figs. 2 and 3; Fig. 5 is a view somewhat similar to Fig. 4 except that a post of the assembly has been advanced away from a body of the assembly and a pair of hooks of the assembly have moved to positions nearer each other; and Fig. 6-8 are enlarged, fragmentary, side elevational views of a portion of the assembly depicted in Figs. 2-5 and depicting steps of removing an orthodontic archwire from an archwire slot of an orthodontic appliance.

Detailed Description of the Preferred Embodiments

A hand instrument 10 for removing an orthodontic archwire from an archwire slot of an orthodontic appliance is illustrated in Fig. 1 and is broadly designated by the numeral 10. The hand instrument 10 includes an elongated handle 12 having a middle portion with a generally rectangular cross-sectional shape. Preferably, the four sides of the middle portion are provided with a grooved gripping surface 14 for enhancing the user's grasp of the handle 12.

Optionally, a rear portion of the handle 12 is provided with an archwire insertion tool such as tip 16. The tip 16 is useful for inserting archwires into spring clips of self- releasing, self-ligating orthodontic appliances such as the appliances described in the aforementioned U.S. Patent Nos. 6,582,226, 7,140,876, and 7,217,125 and 7 ',377 ',777 '. The tip 16 has a groove for receiving an archwire and guiding the archwire into and through the opening of the spring clips mentioned above.

A lever 18 is pivotally connected to the handle 12 by a machine screw 20. Preferably, the lever 18 includes a grooved gripping surface similar to gripping surface 14. A compression spring 22 is received in a cylindrical cavity of a front portion of the handle 12 and a somewhat shallower cylindrical cavity of a front portion of the lever 18. The spring 22 tends to urge the front portions of the handle 12 and the lever 18 away from each other in an arc about the central axis of the screw 20. However, the orthodontic practitioner can move the front portions of the handle 12 and the lever 18 in directions toward each other against the bias of the spring 22 by using finger pressure to move the rear end portion of the lever 18 in a direction toward the central portion of the handle 12.

The hand instrument 10 also includes an assembly 24 that is pivotally connected to the front end portions of the handle 12 and the lever 18. The assembly 24 is shown in more detail in Figs. 2-5 and includes a body 26 with an outer, circular flange 28 and an adjacent groove 30 that circumscribes the body 26 along a circular path. The groove 30 presents a receptacle for receiving a somewhat "C"-shaped support 32 (see Fig. IA) that is provided on the front end portion of the handle 12 , with the flange 28 being received between the support 32 and an adjacent front section of the handle 12.

A pair of arms 34 extends along opposite sides of the body 26. Each of the arms 34 includes an outer end portion with a hook 36. The shape of the hook 36 in the embodiment shown in Fig. 2 somewhat resembles a "J" hook, although other shapes are also possible. For example, the hooks 36 could have an "L"-shaped configuration or any other shape suitable for engaging an orthodontic archwire as described in more detail below.

Each of the arms 34 includes an elongated rib 38 remote from its respective hook 36. Each rib 38 has a semi-cylindrical configuration in cross-sectional view, and is received in a mating channel of the body 26. The ribs 38 in combination with the corresponding channel enable the hooks 36 to move in directions toward and away from each other. More particularly, and in this embodiment, each arm 34 is pivotally movable in an arc about the central axis of its rib 38 such that the corresponding hook 36 is able to move either toward or away from the other hook 36.

The assembly 24 also includes an elongated post 40 having a bifurcated front or outer end portion with a first protrusion 42, a second protrusion 44 and a recess 46 (see, e.g., Fig. 2) located between the first protrusion 42 and the second protrusion 44. The ribs 38 each include a central groove 41 that is represented in dashed lines along its periphery in Fig. 2. The post 40 extends into the grooves 41 and essentially precludes lateral movement of the arms 34 in directions along the central axis of the ribs 38. As such, the grooves 41 serve to retain the arms 34 in coupled relationship to the body 26.

The post 40 includes a central portion with a cylindrical configuration that is received in a matching cylindrical passageway extending through the body 26. The post 40 is movable along the passageway of the body 26 in directions along its longitudinal axis between an extended position and a retracted position. In Figs. 2-4, the post 40 is shown in its retracted position wherein the protrusions 42, 44 are spaced from the outer ends of the hooks 36. In Fig. 5, the post 40 is shown in its extended position wherein the protrusions 42, 44 are adjacent the outer ends of the hooks 36. The central portion of each arm 34 includes a lateral extension 48 having a cavity for receiving the front end portion of the post 40. The cavity includes a cam section 50 (see, e.g., Figs. 4 and 5) that, in this embodiment, has configuration resembling half of a truncated cone. The cavity of the extension 48 straddles the post 40 when the post is received in the passageway of the body 26.

The front end portion of the post 40 also includes a cam section 52 with a truncated conical configuration that matches the configuration of the cam section 50. When the post 40 is in its retracted position as shown in Figs. 2-4, the cam section 52 of the post 40 bears against the cam sections 50 of the arms 34 and retains the hooks 50 in their fully spaced- apart positions as shown in Figs. 3 and 4. Preferably, the spacing between the hooks 36 when the post 40 is retracted is at least slightly wider than the overall mesial-distal width of the widest orthodontic appliance that is expected to be encountered in use. The assembly 24 also includes a pair of compression springs 54 that extend through respective cylindrical passages of the body 26. The springs 54 as depicted in Figs. 4 and 5 are located in the body 26 rearward of the grooves that receive the ribs 38 and extend along opposite sides of the passageway receiving the post 40. In Fig. 2, a pair of dashed circles represent the passages receiving the springs 54. Each end of the springs 54 bears against a rear portion of one of the arms 34 and together tend to urge the rear portions in directions away from each other. As the post 40 is advanced from its retracted position shown in Figs. 2-4 and toward its extended position as shown in Fig. 5, the cam section 52 of the post 40 moves away from the cam sections 50. Such movement releases the arms 34, and enables the springs 54 to pivot the arms 34 about the central axis of the ribs 38 such that the hooks 36 simultaneously move in an arc in directions toward each other.

A rear end portion of the post 40 includes a neck 56 (see Figs. 2 and 3) that extends about the periphery of the post 40 along a circular path. The neck 56 is received in a slot provided in the front end portion of the lever 18. The post 40 also extends through a circular passage in the front end portion of the handle 12, as indicated by the dashed lines in Fig IA.

The body 26 and the post 40 are pivotally connected to the handle 12 and the lever 18 respectively. Consequently, the assembly 24 is rotatable in an arc in either direction about the longitudinal axis of the post 40. As the assembly 24 pivots, the neck 56 of the post 40 turns in the slot provided in the front end portion of the lever 18 and the body 26 simultaneously pivots by movement of the groove 30 along the "C"-shaped configuration of the support 32 of the handle 12. Preferably, the assembly 24 is rotatable at least 360° in an arc about the longitudinal axis of the post 40 to any orientation as may be desired by the practitioner to facilitate access to orthodontic appliances that are located in various regions of the oral cavity.

The assembly 24 also includes an index pin 58 that is received in a matching channel that extends along the periphery of the post 40 in a direction parallel to its longitudinal axis. The index pin 58 is shown in dashed lines in Figs. 3-5. As the post 40 moves in a longitudinal direction relative to the body 26, the index pin 58 slides along a channel 59 (shown only in Fig. 3) formed in the body 26.

The index pin 58 serves to retain the post 40 in proper rotational orientation relative to the body 26, so that both the body 26 and the post 40 move together as the assembly 24 is pivoted about the longitudinal axis of the post 40. The rotational orientation of the hooks 36 relative to the body 26 is also maintained as the assembly is pivoted due to the orientation of the elongated ribs 38 and mating grooves.

An exemplary use of the hand instrument 10 in conjunction with an orthodontic appliance 60 will now be described with reference to Figs. 6-8. The appliance 60 in this example is a self-ligating bracket that is adapted to be secured to a lingual surface of a patient's non-molar tooth. Alternatively, the hand instrument 10 may be used with other types of self-ligating orthodontic appliances, such as a lingual molar appliance, a facial molar appliance or a facial non-molar appliance. The hand instrument 10 may also find utility in releasing archwires from appliances that are not self-ligating appliances.

The appliance 60 includes a body 62 with an elongated archwire slot 64 that extends in a generally mesial-distal direction. The archwire slot 64 has a generally "U"- shaped configuration in cross-sectional view that is adapted to receive an elongated archwire 66. In this example, the archwire 66 has a rectangular cross-sectional configuration that is complemental to the cross-sectional configuration of the archwire slot

64, although other shapes are also possible. For example, the archwire 66 may have a circular configuration in cross-sectional view.

The body 62 of the appliance 60 includes two protrusions or pegs 68 (only one is shown) that extend in a mesial-distal direction from opposite sides of the body 62. Each peg 68 supports a ligating clip (not shown) for releasably retaining the archwire 66 in the archwire slot 64. The clips are made of a resilient material such as nitinol and optionally have a generally "C"-shaped configuration. The clips are sufficiently stiff to retain the archwire 66 in the archwire slot 64 during the course of treatment so long as the forces exerted by the archwire 66 on the appliance 60 are below a certain minimum value in a direction opposite to the direction of insertion of the archwire 66 into the archwire slot 64. In the exemplary appliance 60 illustrated, the archwire 66 is inserted into the archwire slot 64 by moving the same in a downward direction viewing Figs. 6-8.

Preferably, whenever the forces exerted by the archwire 66 on the appliance 60 in an upward direction (viewing Figs. 6-8) are greater than the minimum value mentioned above, as might occur when unexpectedly high forces are encountered, the sides or arms of the clip deflect outwardly and away from each other to open the clip and release the archwire 66 from the archwire slot 64. However, the minimum value is sufficiently high to prevent the archwire 66 from releasing from the archwire slot 64 during the normal course of orthodontic treatment. As such, the archwire 66 can exert forces on the appliance 60 sufficient to carry out the treatment program.

Optionally, the body 62 and the clip have matching, generally oval-shaped external profiles when viewed in directions along the archwire slot 64. Furthermore, the clips have openings that are aligned with the opening of the body 62 that leads to the archwire slot 64. The appliance 60 also includes a neck 70 that interconnects the body 62 to a base (not shown) of the appliance 60. Although also not illustrated in the drawings, the appliance 60 may have one or more tiewings that oriented in a generally occlusal direction and/or a generally gingival direction.

Additional details and optional aspects of the exemplary appliance 60 are set out in applicant's co-pending U.S. Patent Application entitled "LOW PROFILE SELF- LIGATING ORTHODONTIC APPLIANCE WITH CLIP", Serial No. 61/084,691. Additional details and options regarding the clips and possible clip forces are described in U.S. Patent Nos. 6,302,688 and 6,582,226.

In Fig. 6, the hand instrument 10 has been manipulated such that the hooks 36 have been placed around the archwire 66 (or below the archwire 66 in this view). However, only one hook 36 has been illustrated in Figs. 6-8 to facilitate viewing. In Fig. 6, the post 40 is shown in its fully retracted position. The lever 18 has not been moved by the user at this point in time and the arms 34 remain spread apart from each other to their maximum extent. The relatively wide spacing of the arms 34 while the post 40 is retracted facilitates placing the hooks 36 around the archwire 66 without undue contact with the appliance 60. After the hooks 36 are placed as shown in Fig. 6, the user exerts finger pressure against the lever 18 to pivot the lever 18 relative to the handle 12 against the bias presented by the spring 22. As the lever 18 is pivoted, the front end portion of the lever 18 descends (viewing Figs. 1 and IA) and urges the post 40 in a downward direction relative to the body 26. As the post 40 moves downward from a retracted position to an extended position, the cam section 52 of the post 40 first slides along and then disengages the cam sections 50 of the extensions 48, enabling the springs 54 to move the arms 34 such that the hooks 36 simultaneously advance in directions toward each other. The cam sections 50, 52, together with the ribs 38 and the mating channels, consequently comprise a coupling connecting the arms 34 to the body 26 for enabling movement of the hooks 36 in directions toward each other as the post 40 moves away from the body 26 and toward the appliance 60.

The hooks 36 shift toward each other due to the bias force presented by the springs 54 until contacting the mesial and distal sides or other extremities of the appliance 60. In this example, the hooks 36 contact the outer sides of the pegs 68 and the springs 54 enable the hooks 36 to lightly bear against the pegs 68 during subsequent steps of operation. However, as an alternative, the assembly 24 could be constructed to limit inward movement of the hooks 36 to positions that are spaced apart from each other a distance that is slightly greater than the overall mesial-distal width of the appliance 60 when the post 40 is fully extended.

As the lever 18 continues to move relative to the handle 12, the post 40 advances until it comes into contact with the appliance 60. Optionally, the body 62 of the appliance 60 includes recesses or other structure that matingly receives one or both of the protrusions 42, 44 in order to facilitate steady and properly aligned contact of the post 40 with the appliance 60 during subsequent steps.

As the post 40 continues to advance, the hooks 36 move in an upward direction (viewing the drawings) to contact the archwire 66. In practice, the hooks 36 may contact the archwire 66 either before or after the protrusions 42, 44 engage the appliance 60, depending upon the position of the hand instrument 10 relative to the appliance 60. However, at some point during movement of the lever 18, the hooks 36 bear against the archwire 66 in an upward direction while the protrusions 42, 44 bear against the appliance body 62 in a downward direction. This step is shown in Fig. 7. Subsequent movement of the lever 18 relative to the handle 12 initiates movement of the archwire 66 in an upward direction relative to the archwire slot 64. The hooks 36 continue to ascend while lifting the archwire 66 out of the archwire slot 64 and against the spring force provided by the ligating clips. Finally, the hooks 36 move the archwire 66 through the opening of the clips, and thereby release the archwire 66 from the archwire slot 64 as represented by Fig. 8.

Advantageously, the movable hooks 36 can accommodate a wide variety of appliances of different widths, so that only a single hand instrument such as the instrument 10 may be needed to release the archwire from all of the various appliances in the oral cavity of the patient. Also, the movable hooks 36 are beneficial when attempting to remove archwires that are relatively small and flexible because the hooks 36 can be moved next to the sides of the appliance and as near each other as possible during an archwire removal procedure regardless of the width of the appliance. In this scenario, undue bending of the archwire is less likely to occur as the archwire passes through the opening of the spring clips.

In addition, the movable hooks 36 facilitate placing the hand instrument in regions of the oral cavity where access is limited. For instance, if the space between adjacent appliances is very small and the appliances are relatively narrow, as might occur in anterior regions of the oral cavity, the lever 18 can be partially actuated by the practitioner to decrease the distance between the hooks 36 before the hooks 36 are placed behind the archwire 66. This enables the hooks 36 to be maneuvered in positions aligned with the sides of the brackets such that the probability of contact with adjacent appliances or teeth is reduced.

Moreover, the assembly 24 can be turned to any convenient orientation about the longitudinal axis of the post 40 to enhance use of the hand instrument 10 with each appliance regardless of the location of the appliance in the oral cavity. The practitioner may elect to turn the assembly 24 relative to the handle 12 in order to better position the protrusions 42, 44 in alignment with a particular appliance, to provide a better grip of the hand instrument and/or to improve the practitioner's view of the area where the appliance is located.

All of the patents and patent applications mentioned herein are expressly incorporated by reference. Moreover, other constructions are possible. For example, the protrusions 42, 44 may be shaped for mating reception with appliance bodies having other configurations, or for mating reception with tiewings or other structure of appliances. As another example, the assembly 24 may be provided with detent structure or other structure that enables the practitioner to detect by tactile feedback when the assembly 24 is in certain, pre-selected rotational orientations relative to the handle 12 (such as four different orientations spaced 90 degrees apart from each other around the axis of rotational). Furthermore, the hand instrument may be constructed with one hook that is stationary and one hook that is movable. As a result, the scope of the invention should not be deemed limited to the specific embodiments set out above, but instead by a fair scope of the claims that follow along with their equivalents.

Claims

Claims:

1. A hand instrument for removing an orthodontic archwire from the archwire slot of an orthodontic appliance comprising: a body; a pair of arms extending along opposite sides of the body, each of the arms having an outer end portion with a hook; a post connected to the body and movable relative to the body, the post having an outer end portion extending between the hooks; and a coupling connecting at least one of the arms to the body for enabling movement of at least one of the hooks in a direction toward the other hook as the post moves in a direction away from the body.

2. A hand instrument according to claim 1 wherein the body includes a passage and wherein the post extends through the passage.

3. A hand instrument according to claim 1 and further comprising at least one spring for biasing at least one of the hooks in a direction toward the other hook.

4. A hand instrument according to claim 1 and further comprising at least one cam section for moving at least one hook in a direction away from the other hook as the outer end portion of the post moves in a direction toward the body.

5. A hand instrument according to claim 1 wherein the outer end portion of the post includes a recess for receiving an archwire.

6. A hand instrument according to claim 1 wherein the coupling comprising a pivotal coupling.

7. A hand instrument for removing an orthodontic archwire from an archwire slot of an orthodontic appliance comprising: a handle; a lever pivotally connected to the handle; a body; a pair of arms extending along opposite sides of the body, each of the arms having an outer end portion with a hook; an elongated post connected to the body and having an outer end portion extending between the hooks, wherein one of the post and the pair of arms is connected to the lever and movable relative to the body as the lever is moved relative to the handle, and wherein the body is pivotally connected to the handle for movement of the body relative to the handle in an arc about the longitudinal axis of the post.

8. A hand instrument according to claim 7 further comprising a coupling connecting at least one of the arms to the body for enabling movement of at least one of the hooks in a direction toward the other hook.

9. A hand instrument according to claim 8 wherein the coupling enables movement of at least one of the hooks in a direction toward the other hook as the post moves in a direction away from the body.

10. A hand instrument according to claim 9 further comprising at least one spring for biasing at least one of the hooks in a direction toward the other hook.

11. A hand instrument according to claim 10 and further comprising at least one cam section for moving at least one hook in a direction away from the other hook as the outer end portion of the post moves in a direction toward the body.

12. A hand instrument according to claim 7 wherein the body includes a passage and wherein the post extends through the passage.

13. A hand instrument according to claim 7 wherein the outer end portion of the post includes a recess for receiving an archwire.

14. A hand instrument according to claim 7 wherein the coupling comprising a pivotal coupling.

15. A hand instrument according to claim 7 wherein the post is connected to the lever and wherein the pair of arms is movable in directions toward each other.

16. A hand instrument according to claim 7 wherein the body is pivotally connected to the handle for movement through an arc of at least 360 degrees.

17. A method for removing an orthodontic archwire from an archwire slot of an orthodontic appliance comprising: placing a pair of hooks along opposite sides of the appliance and in positions extending at least partially around the archwires; moving a post along a path between the hooks and toward a position for contact with the appliance; shifting at least one of the hooks in a direction toward the other hook and toward a position nearer to the appliance; and urging the post in a direction against the appliance while moving the hooks in a generally opposite direction in order to remove the archwire from the archwire slot of the appliance.

18. A method according to claim 17 wherein the act of moving the post includes the act of moving an outer end portion of the post into a recess of the appliance.

19. A method according to claim 17 wherein the act of moving the hooks includes the act of urging the archwire against at least one spring clip of the appliance.

20. A method according to claim 17 wherein the post includes a longitudinal axis, and including the act of pivotally moving the post and the pair of hooks together about the longitudinal axis of the post.

21. A method according to claim 17 wherein the act of shifting at least one hook is carried out by moving the hook about a pivot axis.

22. A method according to claim 17 and including the act of moving at least one hook toward the other hook before carrying out the act of placing the pair of hooks along opposite sides of the appliance.