TOOTH SUPPORT AND ALIGNMENT

Technical Field

The field of the invention generally relates to orthodontic devices such as retainers having a polymer based labial bow being attached to wire supporting members having non-linear, substantially U-shaped securing ends.

Cross-Reference to Related Applications

This application claims priority to provisional application no. 62/280,327, filed on January 19, 2016. The contents of the provisional application are incorporated herein in their entirety by reference.

Background

Dental braces or retainers are used in orthodontics to align teeth and their position with regard to a person's bite. They are often used to correct malocclusions such as underbites, overbites, cross bites and open bites, or crooked teeth and various other flaws of teeth and jaws, whether cosmetic or structural. Dental retainers are often used in conjunction with other orthodontic appliances to widen the palate or jaws or otherwise shape the teeth and jaws. The labial bow is a component in dental retainers which helps in retracting and retaining the anterior teeth while also contributing to the retention of the appliance.

The conventional labial bow consists of a labial wire that is covered with clear acrylic. One notable example is the Inman Aligner. The conventional acrylic covered labial bow covers more tooth surface for greater and faster tooth rotation and/or greater tooth stability. One disadvantage of this type of bow is that it is very bulky with a thickness of about 2-3 mm. While this thickness provides increased durability, the device is uncomfortable for the patient due to its size. For example, often times, the patient is unable to articulate well due to the bulk and weight of the device. Clinicians often need to make adjustments to the labial bow if they notice the orthodontic appliance is not fully functioning in its intended way. These adjustments include taking a three prong plier to bend the labial bow in certain ways to create more force on a tooth or teeth to create the desired alignment. However, since acrylic covered steel wires are so rigid, the acrylic material will often crack during the adjustment process. Lastly, the conventional labial bow contains a visible metal wire through the clear acrylic which makes the appliance less desirable to the patient.

There is therefore a great need for a labial bow that is capable of covering a larger part of the teeth in order to achieve greater and faster tooth support/rotation, but that lacks the disadvantages of the conventional labial bow. The present invention provides a thin, flat and clear labial bow which lies flat on the teeth without the presence of a wire, and which can be easily connected to wire supporting members in an aesthetically pleasing way.

The following references are provided as background to this invention.

U.S. Patent No. 6,332,774 to Chikami is directed to retainers that include a holding member and a supporting member or wire with the wire is positioned within the holding portion. The wire is retained within the holding member by a clasp type component.

U.S. Patent No. 6,053,730 to Cleary is directed to an orthodontic force module for correcting Class II malocclusions and includes a resilient body and a coupling connected to the body for connecting the body to a selected orthodontic appliance located on the patient's upper jaw. The coupling includes an opening that extends in a reference plane substantially parallel to and preferably containing the longitudinal axis of the body.

According to Cleary, the orientation of the opening provides freedom of movement of the force module when the patient's jaws are opened or closed and reduces the likelihood of fracture of the coupling. Fig. 11 of Cleary shows a coil or spring 23e placed within a sheath 38e or the sheath 38e injection molded around it.

U.S. Patent No. 5,897,313 to Cleary et al. is directed to a force module for moving individual malpositioned teeth or entire dental arches during orthodontic therapy. The module includes an elongated body with couplings at each end of the body for connection to selected orthodontic appliances. The module also includes couplings that have a sleeve portion for receiving end sections of the body and an arm portion connected to each sleeve portion, and the arm portions extend at an obtuse angle relative to the longitudinal axis of the body. Fig. 12 of Cleary shows a force module 510 that is encased at opposite ends in couplers 524, 526. Cleary et al. describes the couplers as being fixed to the force module using a variety of means, such as swaging, pinning, staking, or adhering with an adhesive.

U.S. Patent No. 4,976,614 to Tepper is directed to a removable orthodontic appliance that is seated on the teeth on each side at a midregion by clasps which provide a base for a label filament serving as a reference arch, and curved lingual spring filament which urges the teeth against the reference. The mountings for the filaments comprise open loops having filament receiving sleeves at each end by means of which the positions and angles of the filaments may be adjusted but the filaments may be coupled in solely by mechanical means. A retainer device may use synthetic resin filaments of transparent material to hold the teeth against relapse. The figures disclose clasps formed as tubes that encase the metal wire of the appliance.

U.S. Patent No. 4,875,856 to Grussmark is directed to an orthodontic appliance for closing spaces between two adjacent teeth. The device disclosed includes a bar of elastomeric material or an elastic element and ligature wire means or an inelastic element for securing the bar in place over the labial or buccal or lingual faces of the teeth. The ligature wire means includes ligature wire secured to one or both ends of the bar for mounting and tensioning of the elastomeric bar on adjacent teeth. Grussmark discloses the end of the ligature wire as being coiled around itself to secure the wire in place.

U.S. Patent No. 4,676,745 to Zurita is directed to an orthodontic appliance to provide normal alignment of the teeth. The orthodontic appliance includes a U-shaped band of flexible material having a pair of rearwardly extending arms where the U-shaped band conforms to the labial surface of the dental arch when in position in the mouth. It also includes a pair of anchors each of which is adapted to cooperate with a molar on opposite sides of the mouth to maintain the U-shaped band in position against the labial surface of the dental arch. The orthodontic appliance further includes a resilient member joining the anchors to the arms of the U-shaped band with the resilient member applying a biasing force to the labial surface of the dental arch through the U-shaped band. Fig. 3 of Zurita discloses elongated slide members 22 with protrusions 34 into which arms 14/42 are inserted to mount the U-shaped band to the slide members 22.

U.S. Patent No. 4,059,900 to Orthwein discloses a removable dental restoration for filling an edentulous space defined at each end by a natural tooth, the restoration having at each end a means for resiliently gripping the adjacent natural tooth. In a first embodiment, the gripping means is releasable by application of opposing forces to the longitudinal side walls of the restoration. A second embodiment has the gripping means releasable by applying a simultaneous force to the end wall of each respective gripping means. Further embodiments also have gripping means releasable by application of opposing forces to the longitudinal side walls of the restoration, but the gripping means are formed separately from and attachable to the restoration. Orthwein discloses clasps and gripping means in his Figures 16-18. U.S. Patent No. 4,224,021 to Foxman discloses an adjustable attachment for a labial arch retainer. The retainer is of the type having a palatal section configured to conform to the roof of the mouth of a patient, a pair of extension wires extending anteriorally from the palatal section, an attachment hook provided at the terminal end of each extension wire, and a resilient synthetic band adapted to exert pressure against the teeth of the patient. The adjustable attachment is connected between the resilient band and the attachment hook in a manner which permits the length of the resilient band to be varied thereby permitting adjustment of the pressure exerted against the teeth of the patient. Figures 1 and 2 of Foxman show a connector 9 for connecting to a band 3. The connector includes arms 17/18 that fold over the band.

The disclosure of the above prior art references is incorporated herein in their entirety by reference.

Summary

In one general aspect a dentition retaining apparatus is provided which includes a joint between a holding member and a supporting member, the holding member being elastically deformable and having a length, width, and thickness and terminating in an end segment with at least one hole having a diameter. The supporting member is a wire having a proximal end which is threaded through the hole of the holding member and a distal end. The proximal end of the supporting member is bent so as to form a

substantially U - shape such that the end segment of the holding member lies within an open space created within the U - shape, whereby the U - shaped portion of wire compresses the end segment of the holding member.

Embodiments of the dentition retaining apparatus may include one or more of the following features. For example, the supporting member may include a second bend at a point distal to the U - shaped portion of the wire, the second bend having an angle of between about 90 to about 150 degrees.

The wire may have a diameter which is substantially equal to or greater than the diameter of the at least one hole of the holding member.

The supporting member may include a third bend a point distal to the second bend, the third bend having an obtuse angle such that the portion of the wire distal to the third bend lies along the same line as the proximal end of the wire.

The width of the holding member may be substantially the same along the length of the holding member. The width of the holding member may be between about 2 mm to about 15 mm. The thickness of the holding member may be substantially the same along the length of the holding member.

The thickness of the holding member may be between about .25 mm to about 1.5 mm.

The supporting member may be made of a wire having a diameter of between approximately 0.25 mm and approximately 3 mm.

The at least one hole of the holding member may have a diameter of between approximately 0.25 mm and approximately 3 mm.

The distance from the top to the bottom of the U shaped portion of the supporting member may have a length of between approximately 2 mm and 10 mm.

The supporting member may be made of a metal or polymer material.

The dentition retaining apparatus may include a retainer and/or a labial bow.

The holding member may include a first and second substantially flat surface.

The holding member may be constructed of a clear thermoplastic polymer.

In another general aspect, there is provided a process for forming a dentition retaining apparatus. The process includes providing a holding member, the holding member being elastically deformable and having a length, width, and thickness and terminating in an end segment with at least one hole having a diameter. Providing a supporting member, the supporting member being a wire having a proximal end which is bent so as to form a substantially U - shape. Inserting the proximal end of the wire supporting member through the at least one hole of the holding member, whereby the U - shaped portion of wire compresses the end segment of the holding member.

Embodiments of the process may include one or more of the features described above or the following. For example, the holding member may be formed through pressure forming a piece of thermoplastic material. The holding member may be formed using extrusion. The holding member may be formed using 3D printing. The one or more holes may be made by drilling.

Description of the Drawings

Fig. 1 is a perspective view of a component of a holding member and supporting member of a dental retainer with the supporting member retained within the holding member by a clasp. Fig. 2 is a perspective view of the component of Fig. 1 used in a dental retainer.

Fig. 3 is a perspective view of a holding member or labial bow of the present invention in connection with the wire supporting member of the present invention.

Fig. 4 A is a top perspective view a holding member or labial bow of the present invention in connection with the wire supporting member of the present invention.

Fig. 4B is a bottom perspective view of a holding member or labial bow of the present invention in connection with the wire supporting member of the present invention.

Fig. 5 is a view of the substantially U shaped end of the wire supporting member with arrows indicating the compression forces provided by the supporting member to the end of the bow in order to prevent tearing or fracture of the bow.

Fig. 6 A is a partial side view of the wire supporting member.

Fig. 6B is a partial side view of the holding member or labial bow.

Figs. 7A - 7C illustrate an alternative attachment mechanism between a holding member and a wire supporting member. Detailed Description

Most orthodontic retainers use a stainless steel wire as a holding member to control the position of the upper and lower front teeth. Placing the stainless steel in such a prominent view is undesirable to many patients. Instead of a stainless steel wire, some orthodontic retainers use a polymer instead. The polymer holding member then is joined to a wire supporting member that extends to the back of the teeth. Use of a polymer holding member, however, creates its own problems, such as breakage at the joint formed by the polymer holding member and the metal wire supporting member. Furthermore, the width of the polymer bow can be limited when using a supporting member having a relatively small diameter. This can be due factors such as weak points of the bow existing when the sizing of the bow is tapered from a larger diameter to a relatively smaller diameter, as well as complications with the manufacture of such a varied diameter/width rod. Nevertheless, a larger width is often desirable in cases where greater tooth stability is required or when anterior alignment is needed using an active appliance like the Inman Aligner.

Thus far, it has been difficult to achieve an orthodontic device which balances being able to maintain a large width of the labial bow while maintaining a relatively small diameter of wire supporting member. The present invention includes an attachment assembly that is essentially a metal wire going through the end of the bow which allows for a much smaller joint between the wire and bow than that which is present in the prior art. This smaller attachment assembly or joint allows for the labial bow to retract or move back without the joint getting jammed in the embrasures of the teeth, which is a common disadvantage of larger joints. Furthermore, the smaller attachment assembly allows for the bow to be used for very short teeth without the worry of the patient biting down on the joint or bow. Lastly, the smaller joint of the present invention is more aesthetically appealing than using a larger joint.

The inventor has developed a new assembly for use in dental devices, including dentition devices such as retainers and labial bows. The assembly involves modifications to the first and second end of a U-shaped polymer labial bow as well as the wire supporting members which attach to the first and second end of the polymer bow.

Specifically, the polymer bow of the present invention includes at least one hole located near each end of the polymer bow, each of which are secured to the end of a wire supporting member. The wire supporting member of the present invention is secured to the polymer bow by threading a proximal end through the hole of the bow where the shape of the proximal end of the wire is substantially non-linear such that the wire includes at least two angular bends. Specifically, a first 180° bend is formed from the wire supporting member, which creates a substantially U-shape that restricts the movement of the end of the bow when the wire is threaded through the hole of the bow. The U-shaped portion of the wire is preferably flush with the top and bottom surface of the end of the bow so as to reinforce the strength of this area. The wire is then bent at a point distal from the first bend at an angle that is 90° or more so as to exert a pressure on the attached bow and prevent tearing or fracturing especially around the area where the hole is located.

Without being limited by theory, it is believed that such an assembly allows a force to be exerted which is in the opposition direction of the elongation force exerted on the labial bow when the dental device is being worn and therefore potentially stretched during use. This minimizes the potential of tearing or stretching to occur in the area surrounding the hole. The forces being exerted on the bow are shown in Fig. 5, indicated by arrows. Specifically, there is an inward force being exerted by either side of the U-shape on the two flat surfaces of the bow, which is believed to reinforce the strength in this area.

Further, there are inward forces being exerted by the first and second bend of the wire, one in the direction of elongation of the wire and another in the opposite direction. The design of this securing end therefore allows for reinforcement of the end of the bow, while still providing enough flexibility and rigidity to achieve the intended support to the teeth. Importantly, in cases where a wider labial bow is required for greater tooth stability or for correcting anterior alignment using an active appliance such as the Inman Aligner, the present assembly is ideal as it does not limit the width of the bow to the diameter of the wire supporting member which is relatively smaller in order to be aesthetically pleasing.

Fig. 1 shows a component 10 of a dental retainer in which a portion 10b of the metal wire 3 is inserted within the holding member 2 and a clasp (unnumbered) is secured around the holding member 2 where the metal wire 3 enters. In use, the holding member 2 is pressed against the front teeth and the supporting member 3 generally passes around the outside of the side teeth. Fig. 2 shows the component 10 used with a completed dental retainer. In use, the front teeth are pressed against the holding member 2b and the wire 3 is bent at one end 2a to conform to the teeth against which it is placed. The holding member 2b receives the end of the wire 3 and is held in place with, for example, the clasp illustrated in Fig. 1.

Referring to Figs. 3-6, holding member or first member 105 and a supporting member or second member 110 are shown. The supporting member includes a proximal end 110a which is threaded through hole 101 and distal end 110b which is the end which is farther away from holding member 105. The holding member 105 may be a labial bow having an outside surface 105a which is in substantial contact with the inner lip tissue when the assembly is worn and an inside surface 105b which is in contact with the teeth of the patient when worn. The holding member 105 has a width w which is from about 2mm to about 10 mm, and preferably between about 2.5 mm to about 6 mm so as to provide optimal support and alignment to the teeth. The holding member has a thickness of about .25 mm to about 2 mm. Preferably, the thickness of the holding member is from about .5 mm to about 1 mm. The holding member 105 is preferably flat, but can also include concave surfaces on its tooth facing side so as to conform to the teeth better. This can be accomplished by pressure forming a piece of thermoplastic, for example, with more details to be provided later on in this application.

Referring to Fig. 6A, The supporting member 110 is non-linear at its proximal end. Namely, the supporting member includes a first bend which is bent at an angle "a" of about 180° such that the wire resembles a U-shape and creates a space x substantially between the two portions of wire on either side of the first bend. At a point distal from the first bend, the wire supporting member 110 is bent at an angle "b" of at least 90° and preferably between 95° to about 130° such that the proximal end 110a of the supporting member is in substantial contact with a point distal to the proximal end 110a. An optional third bend may be present at a point distal to the second bend, being bent at an angle "c". Angle c is preferably an obtuse angle which allows the wire supporting member to stay in line and on the same plane as the proximal end of supporting member, as is shown in Figs. 3, 4A, 4B, 5 and 6A.

The materials that may be used to make the wire supporting member include metals, polymers, and combinations of the two. Examples of metals include stainless steel, nickel titanium and other biocompatible metals. Examples of plastics include polyethylene terephthalate, nylon, polyethylene, polypropylene, polyurethane, and other biocompatible plastics. In general, the wire should have sufficient tensile strength to prevent the wire from being plastically deformed when the wire is expanded or retracted. The labial bow may be made of plastics such as polyethylene terephthalate, nylon, polyethylene, polypropylene, polyurethane, and other biocompatible plastics. The plastic may be extruded as a rod, and then oriented and flattened to make the labial bow.

The outer diameter of the wire can range from approximately 0.5 mm and 3.0 mm in diameter. Preferably, the hole 101 which is shown in Fig. 6B has a diameter which is slightly smaller or equal to the outer diameter of the wire. This sizing ensures a tight fit as the supporting member is inserted within the hole and therefore prevents substantial movement of the holding member or labial bow away from the desired location in order to achieve the tooth support intended.

Shown in Fig. 6B is length y, which is defined as the distance between the outer edge of the labial bow and the closest outer edge of the hole 101. Preferably this length y is between about 2 mm - 10 mm, and most preferably between about 4 - 5 mm. It has been found that this length is important in maintaining the strength and integrity of the material at the end of the bow, while also keeping the length small enough so as to have an aesthetically pleasing device. Indeed, it this length y, together with the diameter of the wire supporting member 110, that determines the length z of the U which is formed by the first bend of the wire supporting member. The tip 106 of the holding member 105 is designated as the area at the end of the holding member which rests within the space x within the U shape of the supporting member after the supporting member is threaded through hole 101. Therefore, the length k of the space x is equal to or greater than length y-

The labial bow may have a variety of cross-sectional shapes, such as a circle, oval, square or rectangle. Preferably, the labial bow has a ribbon shape with a rectangular cross section and two substantially flat surfaces 105a and 105b. The figures show a tapering of the ends of the labial bow 105. This feature may be preferred depending on the sizing of the patient's dental anatomy.

Further, length z which is designated as the length of the U-shaped section of wire is between 2 mm and 20 mm, but may be implemented at a length of between 3 mm and 10 mm. The length k of space x may be between about 1 mm - 10 mm, and most preferably is between about 3 - 5 mm.

As is understood to one of ordinary skill in the art, the holding member is a U shaped member with two ends. Therefore, reference to one end or one tip of the holding member is meant to apply to either the first or second ends of the holding member or labial bow. Similarly, each end of the holding member is meant to attach to a wire supporting member. Therefore, reference to one wire supporting member is meant to apply to either first or second supporting members which attach to the first and second holding members, respectively.

To make the dental retaining device/assembly, the holding member is formed or provided in which the holding member terminates in an end segment having a length with a particular cross section. A hole 101 is then made by, for example, drilling, at a point on the flat surface of the holding member such that the hole extends through from surface 105a to surface 105b. A wire supporting member is then constructed according to the features provided above, using pliers, machinery or other similar tools. The wire is then threaded through the hole 101, thus securing the tip of the holding member 105 within the inner space x created by the U-shape. Both ends of the holding member are secured to a supporting member in this way. This unique attachment of the plastic shape with the wire supporting member gives this assembly a unique holding ability which is completely different from anything on the market today.

In a method of using the assembly described herein, a patient uses a dentition retaining apparatus that includes the non-linear, U-shaped supporting members attached to both ends of a holding member, such as a labial bow. As described above, the holding member contains a hole on each end, through which a U- shaped wire supporting member is threaded and secured. The holding member is preferably a ribbon shape and elastically deformable. These characteristics of the holding member along with the manner in which each end is attached to a supporting member allows for greater support and alignment of the teeth than the rod shaped holding members without compromising on appearance by still being able to maintain a small diameter of the wire supporting member, as described above.

A process for forming a dental retainer includes forming a plastic strap, forming a hole through both ends of the plastic strap, forming the proximal end of a wire supporting member such that it is substantially U-shaped, having a first bend being approximately 180 degrees and a second bend being at least 90 degrees at a point distal to the first bend, forming a dental retainer, attaching the labial bow to the dental retainer by threading the wire supporting member through the hole in the plastic strap, and customizing the fit of the labial bow to an individual patient's dental anatomy. The final result is a highly durable clear and stain resistant plastic labial bow that is effectively used in many orthodontic retainers.

Formation of the polymer bow

Polyethylene terephthalate may be extruded into the desired shape such as a ribbon shape or a rod shape and either air or water cooled depending which properties were to be imparted into the plastic. Brittleness and crystallization may be impacted by cooling time of the extruded rod. When desired to impart orientation to the polymer, the cooled rod may be reheated and stretched to orient the polymer rod. This allows the polymer to be suitable for having a shrink memory imparted. It was found that polyethylene

terephthalate can be highly oriented by heating and stretching. This was useful based on the understanding that the more a plastic is oriented, the more it tends to shrink when heated. The rod was worked to achieve an oriented rod that is approximately 1.75 mm in diameter. Although the rod had outer diameter of 1.75 mm, other diameters are expected to be useful, for example over a range of 1.5 to 2.0 mm or 1.25 to 2.5 mm. The outer diameter is selected such that the further processing of the rod will provide a labial bow of the desired dimensions.

The oriented rod is then placed in a heated mold at a temperature ranging from approximately 160 - 230 ° Celsius. The rod then is stamped into a "U" flattened shape that is approximately 0.8 mm in thickness and 3 mm in width, such that the rod now resembles a ribbon or rectangular shape. The "U" shape is of a curve or radius that is approximately that of an average dental arch.

Alternatively, the ribbon shape may be extruded at the first step without the need for the flattening step. In yet another embodiment, the fabrication of the holding member can be achieved by pressure forming a piece of thermoplastic over a plaster or 3D printed mold of the patient's teeth. Next, the portion of the material crossing over the labial surfaces of the teeth may be selectively isolated from the rest of the mold. One or more holes may then be formed through either end of the cut out thermoplastic piece and thereafter the wire supporting members may be attached as has been described above.

Formation of an orthodontic retainer

A plaster mold is made of a mouth of a patient who has just finished an orthodontic treatment in which orthodontic brackets were used to align the teeth. The teeth of such a patient must be held in place for a period of time after the orthodontic brackets have been removed from the teeth. Orthodontists prefer using an orthodontic retainer for this purpose. Such a retainer is formed in part using the plaster mold impression of the teeth of the patients.

As described above, a conventional retainer uses a round or flat stainless steel wire that is in contact with the front teeth and is attached to the molar clasps on the teeth that are in the back of the mouth. Such a retainer is illustrated in Fig. 2. The palate of the mouth is covered with an acrylic wafer of plastic to which the molar clasps are attached. The flat, clear strap of polymer described above is used to replace the stainless steel wire that is currently being used in retainers.

Referring to Figs. 7A-C, another embodiment of the invention is illustrated wherein the attachment between the holding member and the wire supporting member is achieved using a small metal piece such as a staple or rivet, 203, which is pierced through one or more holes 201a and 201b which are formed through holding member 205. The staple 203 is then welded or soldered to the wire supporting member 210 such that a secure attachment is achieved.

While several particular forms of the invention have been illustrated and described, it will be apparent that various modifications and combinations of the invention detailed in the text and drawings can be made without departing from the spirit and scope of the invention. For example, references to materials of construction, methods of construction, specific dimensions, shapes, utilities or applications are also not intended to be limiting in any manner and other materials and dimensions could be substituted and remain within the spirit and scope of the invention. Accordingly, it is not intended that the invention be limited, except as by the appended claims.