Asymmetric expander

Abstract

An expansion device disclosed herein may include a lever arm attachable to a first side of a jaw of a patient; a body portion attachable to a second side of the jaw of the patient; wherein the lever arm is configured to pivot about a fixed pivot point on the body portion, the lever arm configured to pivot first side of the jaw away from the second side of the jaw of the patient while substantially maintaining a relative orientation of the second side of the jaw.

Description

ASYMMETRIC EXPANDERCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of and priority to U.S. Provisional Application 63 / 620,628, filed January 12, 2024, the entire disclosure of which is herein incorporated by reference in its entirety.FIELD

[0002] Disclosed embodiments relate to a device for asymmetric expansion of jaw segments and / or tissue portions, such as to correct a malocclusion.BACKGROUND

[0003] The normal relationship between the upper and lower back teeth is for the upper teeth to nestle between the lower teeth, biased to the outer portion of the occlusal surfaces of lower teeth (i.e. closer to the cheek). When the situation is reversed, such as to have the upper teeth biting onto the lower teeth so that the cheek-facing portion of the lower tooth is closer to the cheek than the equivalent portion of the upper tooth, this is known in the art as a crossbite.

[0004] Crossbites are regarded as a malocclusion because the teeth do not ideally function when the arches are so related. This can lead to impaired chewing function, increased wear of the teeth and predisposes to jaw disorders such as Temporomandibular Joint Dysfunction.SUMMARY

[0005] According to one embodiment, a device includes a lever arm attachable to a first side of a jaw of a patient; a body portion attachable to a second side of the jaw of the patient; wherein the lever arm is configured to pivot about a fixed pivot point on the body portion, the lever arm configured to pivot first side of the jaw away from the second side of the jaw of the patient while substantially maintaining a relative orientation of the second side of the jaw.

[0006] In some embodiments, the lever arm can be attachable to the first side of the jaw with a rigid framework affixed to at least one tooth on the first side of the jaw. The rigid framework can be affixed to the tooth with at least one of dental cement or a ring around the tooth. In an embodiment, the body portion can be attachable to the second side of the jaw with a rigid framework affixed to at least one tooth on the second side of the jaw.

[0007] In some embodiments, the device can include an actuator configured to pivot the lever arm from a first position to a second position. The actuator can include a screw and a nutthreadable on the screw, the nut can be arranged to linearly travel along a length of the screw; and the lever arm can be pivotally disposed on the nut. The nut can include a protrusion received in a channel of the lever arm. The actuator can at least partially be disposed in a channel within the body portion.

[0008] In some embodiments, the fixed pivot point can be a pin affixed to the body portion and the lever arm can include a through hole receiving the pin. The device can include a cap affixed on an end of the pin to retain the lever arm on the pin during use. The cap can be welded on the pin. The device can have a height of approximately 2-10 mm.

[0009] According to one embodiment, a method of asymmetrically expanding a first side of a jaw via an expansion device includes affixing a first rigid framework to a first set of teeth on the first side of the jaw, the first rigid framework affixed to a lever arm of the expansion device, the lever arm being pivotally attached to a body portion about a fixed pivot; affixing a second rigid framework to a second set of teeth on a second side of the jaw, the second rigid framework being affixed to the body portion; actuating an actuator to pivot the lever arm to move the first set of teeth relative to the second set of teeth.

[0010] In an embodiment, during the actuating step, the second set of teeth can be substantially not moved by the expansion device. The actuating step can include rotating a screw disposed within the body portion. A threaded nut can be disposed on the screw and upon rotation of the screw, the threaded nut can translate linearly to pivot the lever arm. A pin can be disposed on the threaded nut that travels within a channel on the lever arm. The expansion device can have a height of approximately 2-10 mm. The lever arm can be fixed to the body portion, while allowing for pivoting motion.

[0011] It should be appreciated that the foregoing concepts, and additional concepts discussed below, may be arranged in any suitable combination, as the present disclosure is not limited in this respect. Further, other advantages and novel features of the present disclosure will become apparent from the following detailed description of various nonlimiting embodiments when considered in conjunction with the accompanying figures.BRIEF DESCRIPTION OF DRAWINGS

[0012] Non-limiting embodiments of the present invention will be described by way of example with reference to the accompanying figures, which are schematic and are not intended to be drawn to scale. In the figures, each identical or nearly identical componentillustrated is typically represented by a single numeral. For purposes of clarity, not every component is labeled in every figure, nor is every component of each embodiment of the invention shown where illustration is not necessary to allow those of ordinary skill in the art to understand the invention. In the figures:

[0013] FIG. 1A is bottom view of a top jaw with a crossbite;

[0014] FIG. IB is a front view of a jaw with a crossbite;

[0015] FIG. 2A is atop down view of an expansion device according to an embodiment in a first position;

[0016] FIG. 2B is a top down view of the expansion device of FIG. 2A in a second position;

[0017] FIGS. 2C and 2D illustrate alternative attachment configurations using the expansion device of FIG. 2A;

[0018] FIG. 3 is an exploded view of an expansion device according to an embodiment;

[0019] FIGS. 4A, 4B, and 4C are various views of an expansion device according to an embodiment in a first position; and

[0020] FIGS. 5A, 5B, and 5C are various views of the expansion device of FIGS. 4A-4C in a second position.DETAILED DESCRIPTION

[0021] The normal relationship between the upper and lower back teeth is for the upper teeth to nestle between the lower teeth, biased to the outer portion of the occlusal surfaces of lower teeth (i.e. closer to the cheek). When the situation is reversed, such as to have the upper teeth biting onto the lower teeth so that the cheek-facing portion of the lower tooth is closer to the cheek than the equivalent portion of the upper tooth, this is known in the art as a crossbite. Crossbites are regarded as a malocclusion because the teeth do not ideally function when the arches are so related. As such, a crossbite can lead to impaired chewing function, increased wear of the teeth and predisposes to jaw disorders such as Temporomandibular Joint Dysfunction.

[0022] Crossbites have been corrected since the 19th century using symmetric expansion devices and various techniques may be used to correct this condition. For example, the prior devices can attach to the teeth on either side of the upper arch. By the application of symmetric pressure to the teeth in the direction of the cheeks each side of the arch, the teethmove laterally, towards the cheeks on each side, and thereby correct the crossbite. The active mechanism most expanders commonly used are screw-driven devices, although some spring- driven devices are also used. These prior devices will apply pressure to move the teeth in equal, but opposite directions.

[0023] The inventor has recognized that existing approximation devices do not allow for an elegant device, that is easy to use, to control asymmetric expansion of a crossbite. For example, one problem facing the orthodontist today is when the crossbite is limited to one side only (which is the most typical scenario), as shown in FIGS. 1A and IB. When the crossbite is only on one side of the jaw 10, the reciprocal action of the expander will cause both sides of the upper jaw to move laterally, not just the side in need of correction. Thus, the teeth having the correct orientation with respect to the upper jaw will now be too far towards the cheek, in relation to the lower teeth. Often, orthodontists will use the arts of the profession to correct this, however, this will take additional treatment time and effort.

[0024] A second, similar, problem facing the orthodontist is when the crossbite is limited to several teeth on one side of the arch, e.g., the canines and premolars, close to the front of the mouth, as seen in FIG. IB. In this situation the use of a typical expander to correct the affected teeth will also cause the back teeth on the affected side to move laterally, like in the previous example, too far towards the check in relation to the lower teeth. In addition, the teeth on the other side will also move too far laterally. This problem can be offset, slightly, by the use of a symmetrical expander that provides expansion biased towards the front of the mouth, known as a “fan” type expander, however, the teeth on the opposite side will still move too far laterally.

[0025] In view of the above, the inventor has recognized the benefits of an asymmetric expansion to controllably correct an asymmetric crossbite. For example, in some embodiments, an application of a rotational force vector limited to the affected teeth can be beneficial. The non-moving portion of the device may have a slight reciprocal movement, but this will be very minimal as the reciprocal rotational pressure will be opposed by compacted bone at the back part of the upper jaw, which does not easily allow tooth movement in this direction. As such, the majority of the force applied by the instant device can be expressed clinically via the movement, or expansion, of the affected teeth. Thus theorthodontist will have a better situation with the affected teeth having been moved into correct position and minimal unwanted movements of other teeth. Further, the inventor has recognized the benefits to devices which are easy to operate and expand by a clinician or the patient themselves.

[0026] Embodiments of the present disclosure include an asymmetric expansion device (referred to herein as “the device”) arranged to move a first side of the jaw relative to the second side, without movement of the second side of the jaw. According to an aspect of the present disclosure, the clinician can actuate the device so as to control the manner in which the first side of the jaw moves away, or towards, the second side of the jaw. The first and second sides of the jaw may include first and second jaw segments and / or first and second teeth segments.

[0027] In some embodiments, the first side of the jaw can be affixed to a lever arm of the device. The lever arm of the device can be mechanically linked to a body portion about a fixed pivot point. In some embodiments, the body portion can be affixed to the second side of the jaw. For example, the first side of the jaw can be reoriented by actuation of the lever arm while the body portion, and thus the second side of the jaw, are in a fixed relationship relative to the remainder of the patient’s anatomy. In some embodiments, the device can further include a first and second rigid framework to attach the pivot arm and body portion to a first set of teeth and a second set of teeth, respectively. In an embodiment, the device can include a mechanical actuator to adjust the relative angular position of the lever arm relative to the body to provide a mechanical advantage to move the first jaw, as will be discussed below. In some embodiments, the actuator can be a nut threaded onto a screw (e.g., a hexagonal set screw). Upon rotation of the screw (e.g., via a complementary tool), the nut can move linearly along the screw. In an embodiment, the nut can be pivotally connected to the lever arm (e.g., via a protrusion received in a corresponding channel) to pivot the arm about the fixed pivot point.

[0028] Although embodiments are shown and described in which a clinician (e.g., a doctor, nurse, surgeon, or other medical professional) activates the device to move the first side of the jaw away, or towards, the second side of the jaw, the device may be used by other individuals in other embodiments. For example, the patient, or the patient’s caregiver may beinstructed on how to use the device. In some embodiments, the device may be actuated by the patient at home, under instruction from the clinician, after insertion of the device by the clinician.

[0029] Turning now to the figures, FIGS. 2A and 2B show embodiments of an approximation device 100 arranged to be attached to first and second sides of the jaw 102, 104. In an embodiment, the device 100 can be constructed from any biocompatible material, for example stainless steel. The device can be dimensioned to have an overall length and width of approximately 8 mm - approximately 15 mm, in some embodiments the length and width can be approximately 10 mm. The device 100 can have an overall height of approximately 2- 10 mm, in some embodiments the height of the device 100 can be approximately 3 mm. The device 100 can be actuated to move the first side of the jaw 102 away the second side of the jaw 104, as shown in the relative location of the first side of the jaw 102 in FIG. 2B as compared to FIG. 2A. As will be appreciated, the first side of the jaw 102 can include a first set of teeth 103 and the second side of the jaw 104 can include a second set of teeth 105. In some embodiments, as shown in FIGS. 2A and 2B, the device 100 may be attached to the first side of the jaw 102 and second side of the jaw 104 via a first rigid framework 110 and a second rigid framework 112, respectively. In an embodiment, the first rigid framework 110 and the second rigid framework can be constructed from a rigid biocompatible metal, e.g., stainless steel wires, and formed to conform to the patient’s teeth. In some embodiments, the first and second rigid frameworks 110, 112 can include rings that seat over the teeth 103, 105, or they may have attachments for bonding to the teeth 103, 105. The first and second rigid frameworks 110, 112 can attach to the teeth 103, 105 in any manner as may be known in the art. For example, FIGS. 2C and 2D illustrate alternative attachment configurations of the first and second rigid frameworks 110, 112 on the teeth 103, 105. Where no rings are illustrated on a set of teeth 103, 105, the respective rigid framework can be bonded to the teeth 103, 105 using, for example, dental cement. In some embodiments, only the first rigid framework 110 is attached to the teeth 103 that are being moved relative to the other set of teeth 105.

[0030] As shown in at least FIGS. 2A and 2B, the first and second rigid frameworks 110, 112 can be attachable to the device 100. For example, the first and second rigid frameworks 110,112 can be welded to the lever arm 130 and the body portion 120, respectively. In some embodiments, the device may be configured to be reusable, such that another set of rigid frameworks are attachable to the device 100. As will be appreciated, the entire device 100 may be disposed of after use.

[0031] With reference to FIG. 3, the body portion 120 can have a channel 122 which can be sized to receive a screw 140 and a threaded nut 150, which can function together as an actuator. The screw 140 can be free to rotate within the channel 122 and can axially extend out of the channel so a tool can engage the screw 140. In some embodiments, the threaded nut 150 can be threaded onto the screw 140, via a through hole 152, such that a threaded nut pin 154 extends upwards from the channel 122. While a screw 140 is illustrated herein, other linear actuators can be used to actuate the threaded nut 150 along the length of the channel 122.

[0032] Extending off an end of the channel 122, a length of material can extend substantially perpendicularly. At an opposite end of the length of material from the channel, a pin 124 can extend upward (as shown in FIG. 3) to pivotally attach the lever arm 130 to the body portion 120.

[0033] In an embodiment, the lever arm 130 can be used to transfer forces from the device 100 to the first side of the jaw 102 to move the jaw as shown from FIG. 2A to 2B. The lever arm 130 can be generally “L” shaped. At a comer of the “L” shape, a through hole 132 can be disposed to pivotally receive the pin 124 of the body portion 120. In some embodiments, a cap 160 can be welded onto the top of the pin 124 to prevent the lever arm 130 from dislodging from the device during use. The cap 160 can be affixed to the pin 124 through any known mechanical or chemical means. In some embodiments, the lever arm 130 can additionally include a channel 134 which can receive the pin 154 of the threaded nut 150. The pin 154 can pivot and translate through the channel 134 to permit the conversion of linear movement of the threaded nut 150 within the channel 122 into rotational movement of the lever arm 130 about the pin 124 of the body portion 120.

[0034] As will be appreciated, during expansion, the first side of the jaw 102 may be moveable away from the second side of the jaw 104, however, the first side of the jaw may beeither the left or right side of the mouth. For example, in some embodiments, the device 100 can be inverted, or the assembly mirrored, such that the lever arm 130 is located on an opposite side to what is shown in the figures. According to aspects of the present disclosure, the device is arranged to selectively move first and second sides of the jaw towards, or away, one another.

[0035] FIGS. 4A-4C and 5A-5C illustrate an exemplary travel path of the lever arm 130 to move the first side of the jaw 102 away from the second side of the jaw 104 during an asymmetric expansion of the jaw to correct a crossbite. In FIGS. 4A-4C, the lever arm 130 is shown in a first position. In some embodiments, the first position may be a starting position of the lever arm 130. As shown in FIGS. 4A-4C, in some embodiments, when the lever arm 130 is in the starting position, the threaded nut 150 may be located at or near a first end 126 of the channel 122. As will be appreciated, upon insertion of the device 100 into the patient’s mouth, the first end 126 of the channel 122 may be positioned near a middle or back of the patient’s mouth.

[0036] FIGS. 5A-5C illustrate the device 100 with the lever arm 130 in a second position. In some embodiments, as shown in this view, the second jaw is pivoted from the first position (see FIGS. 4A-4C) to this second position. For example, the lever arm 130 may be rotated about the pin 124 as the threaded nut 150 translates along the screw 140 along a known path to reorient the first side of the jaw 102 to alleviate the crossbite. The device 100 can make use of the actuator to convert linear motion into rotational motion to achieve a mechanical advantage using the lever arm 130. This mechanical advantage allows for guided and expected movement of the first side of the jaw 102 relative to the second side of the jaw 104.

[0037] In some embodiments, the device 100 can be actuated upon rotation of the screw 140. Upon rotation of the screw 140 the threaded nut 150 can be arranged to drive movement of the lever arm. In some embodiments, the screw 140 can be a hexagonal set screw that can be actuated by the clinician to drive movement of the jaws. The nut 150 may be threaded on the screw 140, and arranged to move along a length of the screw as the clinician turns the screw. For example, in some embodiments, the nut may move linearly within the channel (e.g., between first and second positions), but not move, or may only minimally move, in a lateraldirection. The channels also may be arranged to prevent the nut from rotating when the clinician turns the screw.

[0038] As shown in FIGS. 4A-5C, the lever arm may interface with the pin 154 of the threaded nut 150. In some embodiments, a shape of the channel 134 can be an elongate opening in which the pin 154 is moveable while the lever arm pivots about pin 124. In some embodiments, channel 134 may act as a guide channel for guiding movement of lever arm 130. For example, in some embodiments, the channel 134 can be arranged to control the degree to which the lever arm pivots. For example, when the pin 154 hits one of the ends of the channel 134, the lever arm can be prevented from further rotation.

[0039] When the lever arm is in the first position, the threaded nut can be positioned at the first end 126 of the channel 122. As will be appreciated, the threaded nut may be located near the first end or even a distance from the first end in the first position in other embodiments. To move the lever arm 130 relative to base portion 120, the clinician may turn the screw 140, causing the threaded nut 150 to move in a direction away from the first end 126 of the channel 122, towards a second end 128.

[0040] When the clinician turns the screw 140, the threaded nut 150 can move along the length of the screw, (e.g., in a direction away from the first end 126 of the housing). As the nut 150 linearly translates, the pin 154 on the threaded nut 150 can move within the channel 134 of the lever arm 130 to cause the lever arm to pivot about the fixed pivot point about pin 124. This, in turn, may cause the lever arm 130 to push the first side of the jaw 102 away from the second side of the jaw 104. In cases where contraction of the first side of the jaw 102 may be needed, this process can be performed in reverse.

[0041] In one exemplary method of use, a clinician can obtain impression of an upper jaw and or teeth of a patient. This can be completed via a traditional negative impression in a putty-like material, or a digital scan. In some cases where the patient has a crossbite, there will be upper teeth near the front of the mouth (most likely canines and / or premolars), on one side that occlude (bite) inside the lower teeth that would benefit from lateral movement, towards the cheek, while the posterior teeth (e.g., the molars) do not require lateral movement, as seen in FIG. IB. The device can be positioned within the mouth of the patientaccording to the individual needs of the occlusion, to effect a lateral, rotational movement of only the affected teeth. While it is understood that the unaffected teeth may move slightly, this small amount of movement is understood to be clinically insignificant and will be described herein as “substantially maintaining a relative orientation of the second side of the jaw,” or like language.

[0042] The clinician can create custom rigid frameworks (wires) 110, 112 which can be welded, or otherwise affixed, to the device 100. The rigid frameworks can be conformed to fit to the teeth 103, 105. The clinician can then fix the device 100 to the teeth 103, 105 according to the custom plan for attachment, using orthodontic bonding material. Once installed within the mouth of the patient, the clinician can show the patient, or their caregiver, how to activate the device by turning the screw 140.

[0043] The screw 140 may be turned at a slow or rapid pace, depending on the clinician’s preference, or required medical needs. A fast pace (e.g., up to approximately 1 mm per day of movement) is viewed as rapid expansion, when a splitting and distraction of the upper jaw bone is created by a lot of pressure. This is known as a “Skeletal Expansion” as the expansion is effected by the movement of the segment of bone attached to the teeth, and not by the teeth moving through the bone. Alternatively, a slower movement, of around 1 mm per month is effected to achieve a dental tooth movement, known as “Dental Expansion,” this involves the teeth moving through the bone and the bone remodeling accordingly.

[0044] Although the device is shown and described for use to repair a crossbite, the device may be used to approximate tissue and / or jaw segments or other orthodontic procedures.

[0045] Various aspects of the present disclosure may be used alone, in combination, or in a variety of arrangements not specifically discussed in the embodiments described in the foregoing and is therefore not limited in its application to the details and arrangement of components set forth in the foregoing description or illustrated in the drawings. For example, aspects described in one embodiment may be combined in any manner with aspects described in other embodiments.

[0046] Also, the invention may be embodied as a method, of which an example has been provided. The acts performed as part of the method may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include performing some acts simultaneously, even though shown as sequential acts in illustrative embodiments.

[0047] Use of ordinal terms such as “first,” “second,” “third,” etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements.

[0048] Also, the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having,” “containing,” “involving,” and variations thereof herein, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

Claims

CLAIMSWhat is claimed is:

1. An device comprising: a lever arm attachable to a first side of a jaw of a patient; a body portion attachable to a second side of the jaw of the patient; wherein the lever arm is configured to pivot about a fixed pivot point on the body portion, the lever arm configured to pivot first side of the jaw away from the second side of the jaw of the patient while substantially maintaining a relative orientation of the second side of the jaw.

2. The device of claim 1, wherein the lever arm is attachable to the first side of the jaw with a rigid framework affixed to at least one tooth on the first side of the jaw.

3. The device of claim 2, wherein the rigid framework is affixed to the tooth with at least one of dental cement or a ring around the tooth.

4. The device of claim 1, wherein the body portion is attachable to the second side of the jaw with a rigid framework affixed to at least one tooth on the second side of the jaw.

5. The device of claim 4, wherein the rigid framework is affixed to the tooth with at least one of dental cement or a ring around the tooth.

6. The device of claim 1, further comprising an actuator configured to pivot the lever arm from a first position to a second position.

7. The device of claim 6, wherein the actuator includes: a screw; and a nut threadable on the screw, the nut arranged to linearly travel along a length of the screw; wherein the lever arm is pivotally disposed on the nut.

8. The device of claim 7, wherein the nut includes a protrusion received in a channel of the lever arm.

9. The device of claim 6, wherein the actuator is at least partially disposed in a channel within the body portion.

10. The device of claim 1, wherein the fixed pivot point is a pin affixed to the body portion and the lever arm includes a through hole receiving the pin.

11. The device of claim 10, further comprising a cap affixed on an end of the pin to retain the lever arm on the pin during use.

12. The device of claim 11, wherein the cap is welded on the pin.

13. The device of claim 1, wherein the device has a height of approximately 2-10 mm.

14. A method of asymmetrically expanding a first side of a jaw via an expansion device, the method comprising: affixing a first rigid framework to a first set of teeth on the first side of the jaw, the first rigid framework affixed to a lever arm of the expansion device, the lever arm being pivotally attached to a body portion about a fixed pivot; affixing a second rigid framework to a second set of teeth on a second side of the jaw, the second rigid framework being affixed to the body portion; actuating an actuator to pivot the lever arm to move the first set of teeth relative to the second set of teeth.

15. The method of claim 14, where during the actuating step, the second set of teeth are substantially not moved by the expansion device.

16. The method of claim 14, wherein the actuating step includes rotating a screw disposed within the body portion.

17. The method of claim 16, wherein a threaded nut is disposed on the screw and upon rotation of the screw, the threaded nut translates linearly to pivot the lever arm.

18. The method of claim 17, wherein a pin disposed on the threaded nut travels within a channel on the lever arm.

19. The method of claim 14, wherein the expansion device has a height of approximately 2-10 mm.

20. The method of claim 14, wherein the lever arm is fixed to the body portion, while allowing for pivoting motion.

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