Lingual bar assembly

Abstract

An assembly for installation of a lingual retainer for correction of a teeth array. The assembly comprises a platform formed from a plurality of elements for retaining teeth, each element capable of co-operating engagement with at least one adjacent element each element having a tooth engagement surface. The assembly includes a setting jig having a first end formation configured to seat on at least one tooth and a second end formation configured to seat on at least one tooth, the setting jig further comprising at least one retaining arm bridging between the setting jig and the platform to retain the platform in a predetermined attitude relative to the teeth when the jig is seated via the first and second end formations. The assembly includes a handle which connects to the setting jig for installation of the platform

Description

LINGUAL BAR ASSEMBLY.BACKGROUND

[0001] The present invention relates to use and installation of lingual retainers and more particularly relates to an apparatus and method for installing a lingual retainer for retaining an array of teeth. The present invention further relates to an assembly and method for retaining teeth in a predetermined attitude in order to maintain orthodontic correction. More particularly the present invention provides an assembly including a lingual platform, a jig which temporarily holds the lingual platform in said predetermined attitude and a gripping handle which enables convenient setting of the lingual platform in place against an array of teeth. The invention further relates to a patient specific platform applied in situ using a setting jig and handle and which enables accurate fitting against the teeth of a patient. The Platform is formed from a plurality of elements which are adapted to locate against individual teeth of an array of teeth according to a patient specific prescription.

[0002] The invention further provides a lingual platform which comprises a plurality of co - operating elements, each element adapted to adhere to an individual tooth in a teeth array and including an aperture which receives and retains dental glue / adhesive enabling retention of the platform to the teeth via said elements. The invention further provides a lingual retainer platform which includes a plurality of elements which individually conform to a surface configuration of an opposing tooth.

[0003] The present invention also relates to a method for setting a patient specific lingual platform retainer to a tooth array using a jig and a handle to enable placement of the platform in apposition with teeth via the jig. The method comprises placing the platform retainer against a rear surface of an array of teeth, the application of a dental adhesive / glue / cement to the platform surface / s and via a window aperture / opening in each element of the platform, removing the handle and cutting one or more bridges / retainingarms which hold the jig in place to release the jig and leave the platform in apposition with a plurality of teeth.PRIOR ART

[0004] In the field of dentistry, retainers are used to maintain the position of a teeth array which has been the subject of prior orthodontic correction. Permanent retainers overcome the problem of patients who may not be diligent in wearing removable retainers such as those which may be worn at night. Fixed or permanent retainers are located on the rear face of the bottom teeth. One conventional permanent retainer is a metal wire that is mounted on the rear face of teeth to prevent those teeth from migrating back to an original position prior to a correction using such devices as braces. Retainers are very important after the removal of correcting braces. To avoid the painful and forceful shifting of braces after correction, a permanent retainer provides a permanent way to keep corrected teeth in place.

[0005] The retainer is typically chemically bonded to the bottom 4-6 teeth to provide a permanent installation. Other known permanent retainers are manufactured from a composite resin instead of metal wires, but the metal wire retainers are considered more durable. The metal-wired retainers are bonded to teeth using composite resin.

[0006] An orthodontist may recommend a wire retainer behind the teeth immediately or six months after removing braces to ensure that the teeth stay aligned. Some patients have permanent retainers fixed to both their upper and lower teeth. Orthodontists are less likely to recommend a permanent retainer for top teeth rather than on bottom teeth retainers because they have a greater chance of breaking prematurely. Permanent retainers usually involve placement from canine to canine and therefore are stabilizing a front segment of the teeth.

[0007] There are two types of known permanent retainers: a stainless steel wire (braided / flexible stranded, cylindrical, or flattened) and a fiberglass-reinforced composite resin. Not wearing retainers after braces can ultimately lead to an orthodontist suggesting braces be used a second time which is undesirable.

[0008] Permanent retainers, also termed lingual bar retainers according to the known art have both advantages and disadvantages. The obvious advantage of using a permanent lingual retainer is that the user does not have to remember to insert a removable retainer or appliance. If the user forgets to use a removable retainer or is not diligent in its use, insertion can, involve pain as the teeth may have moved as soon as within weeks of non - use. Another advantage of a permanent lingual retainer is that they are essentially invisible from the outside because they are bonded to the rear of the teeth. This differentiates them from some known removable retainers, which display a prominent wire across the front of the teeth and from plastics retainers. Other advantages of a permanent retainer include: it cannot be lost, it is cheaper in the longer term and less likely to be broken.

[0009] Permanent bonded retainers also have some disadvantages. A permanent retainer can make cleaning teeth difficult, as the wire on a bonded retainer can trap bacteria and food and increase the chance of cavities since flossing becomes more difficult. Another disadvantage is that a permanent retainer although not painful, can be uncomfortable or annoying as the tongue constantly touches them. A permanent retainer can degrade over time and may have to be replaced. It is much more difficult to replace a permanent retainer than a removable retainer since it requires the patient to attend the orthodontist to make the installation. Permanent retainers also have the disadvantage that they may increase plaque build- up and trap bacteria. Further disadvantages of permanent retainers include they are more expensive than removable retainers and can break over time, requiring retainer replacement or removal

[0010] The aim with permanent retainers is to ensure a comfortable, durable and long lasting fit. A properly fitted retainer can last decades and it will remain comfortable for the patient provided the retainer is correctly placed. A dentist will normally check the integrity of a retainer each time a patient attends for routine check -ups. Specific dental adhesives / glues / cements are used to retain the retainer and to prevent it from dislodgment.

[0011] In the prior art, lingual retainers may comprise a series of woven strands to form a lingual wire. The failure rate of wires employed in the prior art can be up to 40%. Salivawhich is rich in calcium slowly permeates into and erodes the wire which forms a precipitate which attracts bacteria ultimately degrading [de bonding] the strands which make up the wire. This can lead to bacteria build up and eventually gum disease and infections. It also leads to calcium build up causing deposits around the wire and between the teeth. In the prior art, the wire is manually adjusted -bent / shaped - to accommodate the teeth array to be restrained. The contact with the teeth is poor and relies on embedded wire in glue / cement / resin. On installation it is difficult to hold the wire and glue at the same time. In essence the wire retainers are clumsy and prone to failure which is unacceptable for a permanent installation. There is a need to continually improve the efficiency, integrity and accurate production of lingual retainers and particularly permanent lingual retainers which are patient specific, easy to install, durable, comfortable for the patient and which reduce the incidence of decay and allows access for teeth cleaning.INVENTION

[0012] Outlined broadly below are embodiments and features of the invention to enable it be better understood, and in order that the present contribution to and improvement over the current art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims.

[0013] In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components as set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways.

[0014] Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other variations on the assemblies, structures, methods and systems for carrying out the purposes of the present invention.[0015 A reference to patient specific platform can be taken to include a reference to any platform which is capable of adaption to an individual patient or can be adapted to more than one patent. A reference to an opening in the elements of the platform can be taken to include a reference to any aperture / s, opening or openings in each element having any peripheral configuration and which receives a glue / adhesive / cement. A reference to glue, resin, cement or adhesive are each interchangeable terms and generically includes any material which is suitable for fixation of each element of a platform against a tooth.

[0016] The lingual platform according to one embodiment of the invention has a series of elements which attach on the rear of every tooth surface from one bottom row canine to the other canine. Each element has a substantially rectangular window which provides Cement / glue access to the tooth. Retention is enabled by both chemical and mechanical fixation.

[0017] The platform leads to improved hygiene allowed by the patient specific improved fit of the platform. According to the invention there is improved surface area contact between tooth and retainer. Each element of the retainer is preferably around 6mm across and 3-6mm high- preferably 60-90% of the width the tooth and 15-30% of the height of the targeted tooth and are interconnected, generally encompassing up to 8 teeth.. Ideally there is approximately 15 square millimetres of contact between each element of the platform and a tooth. These dimensions and contact areas may vary according to the size of the teeth to which the retainer is attached. The lingual platform according to one embodiment of the invention has a series of elements which attach on every tooth surface from one bottom row canine to the other canine. Each element has a (substantially) anatomically tooth specific window, which could be oval, circular or rectangular in shape which provides cement / glue access to the tooth. Retention is enabled by both chemical and mechanical fixation. The platform is preferably manufactured from biocompatible Cobalt Chromium or reinforced composite resin. Other materials are contemplated including nylon, platinum, gold alloy, copper zinc palladium non precious nickel and zircon.

[0018] The present invention adapts to the rear surface contour or anatomy of the tooth. To enable this, the platform is customed to conform to an individual patient which renders the platforms patient specific, as each element of the platform conforms to each tooth in a teeth array to which the platform is attached. The Platform according to one embodiment, comprises a series of individual elements each configured according to prescription to conform to the shape of the back surface of a tooth opposed by one of the elements. The platform can be prepared using a laser process, casting or a 3D printing process, which prepares the front surface of the platform for close anatomical engagement with a back surface of a tooth in a tooth array of a patient.

[0019] According to a preferred embodiment a handle is employed to engage and hold the platform via an associated jig which is removed after application of the platform. The jig has a dual purpose of retaining the lingual platform and engaging with back teeth so as to correctly position the platform prior to application of a dental glue / resin. One aim is to minimise the profile of a joiner between the elements of the platform. This leaves a larger flossing pathway and access. The size of each element of the platform relative to the tooth to which each element is fitted, is minimised to enhance prospects for oral hygiene. Advantages of the present invention include increased contact area compared to wire, improved hygiene due to the tailored intimacy of fit, ease of installation and in this regard, the accurate setting of the platform prior to final gluing and retention of the platform during the gluing / cementing stage.

[0020] The jig which is prepared / designed as a temporary support carrier for the platform includes at least one strut / bridge connector which are cut to release the jig when the platform is cemented in place. Preferably two such bridge connectors are employed. The platform can be prepared / created by laser sintering, casting or 3D printing which conform outer surfaces of the platform formed by individual tooth opposing elements, to an opposing back surface of a tooth to which each element of the platform is connected. The jig to which the platform is attached is cut away from the platform by severing the supporting struts bridge connections. These are polished back using an instrument such as an abrasive or bur to a smooth surface to ensure no patient tongue abrasion. A handle isprovided to assist the ease of insertion of the retainer into the correct position, hold it in place while cementing and subsequent removal of the jig.

[0021] In one broad form the present invention comprises: an assembly for installation of a lingual retainer; the assembly comprising; a platform for retaining teeth formed from a plurality of elements, each element capable of co -operating engagement with at least one adjacent element via a connection, each element having a preformed tooth engagement surface; a jig having a first end configured to seat on a first tooth and a second end configured to seat on a second tooth, the jig further comprising at least one retaining arm which spans between the jig and platform to retain the platform in a predetermined attitude; a holder / handle which engages and retains the jig enabling a user to locate the platform against the teeth and remove the jig after installation of the platform.

[0022] The jig is for setting the platform in place and has connections at the most distal point of the platform. The handle engages and retains the jig enabling a user to seat the platform most efficiently and intimately against the teeth, hold in place for cementing to the teeth and to remove the jig after installation of the platform.

[0023] In its broadest for the present invention comprises: an assembly for installation of a lingual retainer for correction of a teeth array; the assembly comprising; a platform for retaining teeth formed from a plurality of elements, each element capable of co -operating engagement with at least one adjacent element via a connection therebetween, each element having a tooth engagement surface; a setting jig having a first end formation configured to seat on a first tooth and a second end formation configured to seat on a second tooth, the jig further comprising at least oneretaining arm which spans between the setting jig and platform to retain the platform in a predetermined attitude relative to the teeth when the jig is seated on the first and second teeth.

[0024] Each element of the platform opposes a tooth in the array of teeth while in said co -operating engagement with said at least one adjacent element. Each element and its tooth engagement surface are preformed. The setting jig is connected to the platform via a least one retaining arm but it is preferred to have two retaining / connecting arms extending radially one at either end extremities of the platform and readily severable therefrom. According to a preferred embodiment, the assembly is configured to be patient specific, with the platform fixed to the rear of a patient’s front teeth using a selected suitable adhesive or glue or cement.

[0025] Preferably each element of the platform is selected from shapes including circular, triangular, square polygonal, rectangular, and includes a central opening, with each opening configured to receive the adhesive facilitating retention of the platform against an opposing tooth of the front teeth array. Each opening can have a variety of configurations according to each platform design and selected from shapes including circular, star shaped, hexagonal, polygonal, square, triangular, rectangular.

[0026] To facilitate adhesion of each element to a tooth elements may include formations such as radial protrusions extending from the outer circumference which can increase the contact surface area. In another embodiment the opening in an element includes at least one recess extending radially from the central opening.

[0027] The assembly further comprises a holder including a handle which engages with and allows retention of the jig enabling seating / setting of the jig on the first and second teeth which are preferably molars and setting of the platform against the back surfaces of the array of front teeth in preparation for application of an adhesive.

[0028] In another broad form the present invention comprises: an assembly for installation of a lingual retainer; the assembly comprising; a platform formed from a plurality of elements for retaining teeth, each element opposing a tooth in an array of teeth and capable of co -operating engagement with at least one adjacent element via a connection, each element having a preformed tooth engagement surface; each said elements having a tooth engaging surface, a central opening an at least one radially disposed extension and at least one radially disposed void. a jig having a first end configured to seat on a first supporting tooth and a second end configured to seat on a second supporting tooth, the jig further comprising at least one retaining arm forming a connecting bridge which spans between the jig and platform to retain the platform in a predetermined attitude against the teeth in the teeth array; a holder which engages and retains the jig enabling a user to locate the platform against the teeth and remove the jig after installation of the platform.

[0029] In another broad form the present invention comprises: a platform for retaining teeth formed from a plurality of elements, each element capable of co -operating engagement with at least one adjacent element via a connection, each element having a tooth engagement surface; the platform connected to a jig having a first end configured to seat on a first tooth and a second end configured to seat on a second tooth, the jig further comprising at least one retaining arm which spans between the jig and platform to retain the platform in a predetermined attitude;the jig receiving a holder which engages and retains the jig enabling a user to locate the platform against the teeth and remove the jig after installation of the platform.

[0030] In another broad form the present invention comprises: a jig for use in the installation of a lingual retainer assembly, the jig having a first abutment configured to seat on at least one molar tooth on one side of a front teeth array and a second abutment configured to seat on at least one other molar tooth on an opposite side of the teeth array, the jig further comprising at least one connecting bridge which spans between the abutments to retain the platform in a predetermined attitude and position against a surface of a plurality of teeth in the teeth array.

[0031] In another broad form the present invention comprises: an assembly for installation of a lingual retainer against an array of teeth; the assembly comprising; a platform for retaining teeth formed from a plurality of elements, each element capable of co -operating engagement with at least one adjacent element via a connection therebetween, each element having a tooth engagement surface; and a holder which engages and retains the jig enabling a user to locate the platform against the teeth, the jig further comprising at least one retaining arm which spans between the jig and platform to retain the platform in a predetermined attitude for engagement with the teeth array.

[0032] In another broad form of a method aspect, the present invention comprises: a method for installation of a lingual retainer using an assembly comprising; a platform for retaining teeth formed from a plurality of elements, each element capable of co -operating engagement with at least one adjacent element via a connection, each element having a tooth engagement surface;a jig having a first end configured to seat on a first tooth and a second end configured to seat on a second tooth, the jig further comprising at least one retaining arm forming a bridge which spans between the jig and platform to retain the platform in a predetermined attitude; a positioning handle which engages and retains the jig enabling a user to locate the platform against the teeth; the method comprising the steps of . a) taking the positioning handle and placing the jig on supporting teeth and locating the platform against a surface of each tooth of a selected tooth array; b) applying dental glue to selected platform elements to adhere the platform and each element to teeth opposing said elements; c) upon setting of the glue; cutting retaining arms from the platform to release the jig; d) using the positioning handle to remove the jig; e) finishing the retainer by smoothing surfaces.

[0033] According to a preferred embodiment, the teeth are prepared to receive the platform elements. Bonding procedures vary. Accordingly, the fitting surface is prepared in the most appropriate method relevant to the cement or luting agent. The preparation is influenced by the type of bonding procedures selected. The fitting surface is prepared in the most appropriate method relevant to the cement or luting agent.

[0034] These, together with other objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the description forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated preferred embodiments of the invention.

[0035] The present invention provides an alternative to the known prior art and the shortcomings identified. The foregoing and other objects and advantages of the invention will appear from the description to follow. In the description reference is made to the accompanying representations, which forms a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments will be described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the invention. In the accompanying illustrations, like reference characters designate the same or similar parts throughout the several views. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is best defined by the statements of invention.BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:Figures 1 shows a top view of the lingual platform and setting jig mounted on teeth, according to a preferred embodiment;Figure 2 shows an underside view of the retainer assembly including the platform and jig of figure 1 with placement handle attached.Figure 3 shows a top front view of the retainer assembly including the platform, setting jig and placement handle.Figure 4 shows an underside view of the assembly when placed in situ against teeth.Figure 5 shows the retainer assembly being placed in situ via the finger grippable placement handle.Figure 6 shows a schematic illustration of the geometry of a retainer element and its configurational relationship to a tooth according to one embodiment.Figure 7 shows a schematic illustration of a teeth array with a plurality of teeth engaging elements of different configurations.Figure 8 shows a schematic illustration of a teeth array with a plurality of alternative teeth engaging elements of different configurations.Figure 9 shows a retainer assembly including elements integrated with a setting jig, the elements each including optional radial voidsFigure 10 shows a schematic illustration of a teeth array with a plurality of teeth engaging elements of a serpentine configuration including a recess between elements which allow access for patient teeth flossing.Figure 11 shows a retainer assembly including the elements having the serpentine configuration of figure 9 incorporated with a setting jig.Figure 12 shows a retainer assembly including elements integrated with a jig, the elements having no additional extensions or voids.DETAILED DESCRIPTION

[0037] The present invention will now be described in more detail according to preferred, but non limiting embodiments and with reference to the accompanying illustrations. The examples referred to herein are illustrative and are not to be regarded as limiting the scope of the invention. While various embodiments of the invention have been described herein, it will be appreciated that these are capable of modification and therefore the disclosures herein are not to be construed as limiting of the precise details set forth, but to avail such changes and alterations as fall within the purview of the description.

[0038] Referring to Figure 1 there is shown a top view of an assembly 1 including a lingual platform 2 and setting jig 3 jig according to a preferred embodiment mounted upon abottom set of teeth 4. Jig 3 comprises first and second abutments 5 and 6 which are each configured to respectively engage molar teeth. For example part of abutment 5 engages molar 7 and part of abutment 6 engages molar 8. Abutments 5 and 6 provide a secure foundation for self support and also for supporting lingual platform 2. Setting jig 3 further includes a body 9 which acts as a bridge spanning between abutments 5 and 6. Abutments 5 and 6 are preferably configured to engage two teeth on either side of the bottom teeth array to provide a secure foundation . Body 9 includes openings 11 and 12 which receive and retain a placement handle 13 ( see figure 2) to be described in more detail below. Body 9 also includes crescent formation 14 which engages bridging retaining arms 15 and 16 which support platform 2 and hold it against teeth array 4 comprising teeth 17, 18, 19, 20, 21 and 22. Lingual platform 2 comprises a series of individual elements 23, 24, 25, 26, 27 and 28 which respectively oppose teeth 17, 18, 19, 20, 21 and 22. Each element 23, 24, 25, 26, 27 and 28 respectively includes apertures 29, 30, 31, 32, 33 and 34.

[0039] Figure 2 shows with corresponding numbering, an underside view of the lingual platform 2 and setting jig 3 with placement handle 13 attached. Each element 23, 24, 25, 26, 27 and 28 spans preferably 85% of the width of the tooth it opposes and has a height enabling a sufficient contact area with the tooth. Typically, the width of an element would be in the order of 6mm and the height of the element in the order of 3 -8mm with the dimensions variable to suit the tooth size and geometry of the individual patient. The aperture size is a function of the size of the element but whose size and geometry may be varied according to requirements. Typically, the aperture width will be about 4mm less than the overall width of the corresponding element. The height of the aperture will typically be about 4mm less than the overall height of the aperture. Typically, for each element, its width will be greater than its height. Apertures 29, 30, 31, 32, 33 and 34 allow access to dental glue which sets to bind each aperture against the tooth that each opposes. When glue / adhesive is applied to the apertures part of the glue adheres to the tooth exposed through the aperture and another part of the glue engages the element thereby providing a key in lock arrangement. This also avoids exposure of the patient’s tongue to edging around the aperture which might otherwise cause discomfort. A practitioner cancheck for and remove any sharp edges as required. Once lingual platform 2 is set in position jig 3 is removed by cutting away retaining arms 15 and 16.

[0040] From figure 2 it can be seen that bridge body 9 receives via openings 11 and 12 guide protrusions 35 and 36, which preferably engage via snap fit inter fitting. Tab 37 on handle 13 engages an underside of crescent 14 to secure the handle 13 to jig 3. Platform 2 further comprises formations 38, 39, 40, 41 and 42. Each formation is arranged to locate between adjacent teeth in teeth array 4 ( see figures 1 and 3) . For example, formation 39 is interposed between elements 24 and 25 and in situ engages the gap / junction between teeth 18 and 19 shown in figure 1. Similarly for the gaps between remaining teeth, the formations provide a connection to an adjacent element and a change in angle of each element to accommodate the angles and attitudes of the teeth in the teeth array and each particular tooth to which one of the elements is attached. Formations can be fold lines in the platform between elements creating a change in angle of an element. Figure 2 shows the underside of each abutment 5 and 6. The underside profiles are configured to conform to geometry of the teeth on which the abutments sit. Accordingly, abutment 5 has underside profiles 43 and 44 which engages teeth 45 and 46 (see figure 3). Eikewise, abutment 6 has underside profiles 47 and 48 which engage teeth 49 and 50 (see figure 3).

[0041] Figure 3 shows with corresponding numbering for corresponding parts a top view from the front of the retainer assembly including the lingual retainer platform 2, placement handle 13 and mounted on array of bottom teeth array 4. Setting jig 3 comprises first and second abutments 5 and 6 in situ providing a secure foundation for self support and also for supporting lingual platform 2. Bridge 9 of jig 3 is obscured by which spans between abutments 5 and 6. Abutments 5 and 6 are preferably configured to engage two teeth on either side of the bottom teeth array to provide a secure foundation . Bridge body 9 includes openings 11 and 12 which receive and retain a placement handle 13 ( see also figures 2 and 4) to be described in more detail below. Bridge body 9 also includes crescent formation 14 which engages retaining arms 15 and 16 which support platform 2 and hold it against teeth 17, 18, 19, 20, 21 and 22. Eingual platform 2 comprises a series of individual elements 23, 24, 25, 26, 27 and 28 which respectively oppose teeth 17, 18, 19, 20, 21 and 22.

[0042] Figure 4 shows with corresponding numbering, an underside view of the assembly placed in situ. Each element of elements 23, 24, 25, 26, 27 and 28 forming platform 2 respectively include one aperture from the apertures 29, 30, 31, 32, 33 and 34. Apertures 29, 30, 31, 32, 33 and 34 respectively align with teeth 17, 18, 19, 20, 21 and 22. Bridge body 9 includes openings 11 and 12 which receive and retain placement handle 13.. Each element spans the width of the tooth it opposes and has a height sufficient to enable a sufficient contact area with the tooth. Typically the width would be in the order of 6mm and the height in the order of 3 -8mm with the dimensions variable to suit the tooth size and geometry of the individual patient. The aperture size is a function of the size of the element. Typically the aperture width will be about 4mm less than the overall width of the corresponding element. The height of the aperture will typically be about 4mm less than the overall height of the aperture. Typically, for each element, its width will be greater than its height. Apertures allow access to dental glue or other suitable biocompatible adhesive which sets to bind each aperture against the tooth that each opposes. When glue is applied to the apertures part of the glue adhere to the tooth exposed through the aperture and another part of the glue engages the element thereby providing a key in lock arrangement. This also avoids exposure of the patient’s tongue to edging around the aperture which might otherwise cause discomfort. A practitioner can check for and remove any sharp edges as required. Once lingual platform 2 is set in position jig 3 is removed by cutting away retaining arms 15 and 16.

[0043] Figure 5 shows the retainer assembly 1 being placed in situ via the finger grippable placement handle 13. Shown is lingual platform 2 and setting jig 3 with placement handle 13. Placement handle 13 includes a central body 51 terminating at either side in finger grips 52 and 53. The whole assembly 1 is placed in situ by holding grips 52 and 53 using the installing practitioner’s fingers and setting the lingual platform 2 against the back surface of the teeth. Thumb rests 52 and 53 can also be used to hold the whole assembly 1 in place while curing the adhesive cement placed between platform 2 and teeth 17, 18, 19, 20, 21 and 22. The practitioner sets the assembly 1 against the patient’s teeth holding handle 13 via the finger grips 52 and 53.

[0044] Retainer platform 2 is preferably manufactured from biocompatible Chrome cobalt. Other materials are contemplated including platinum, gold alloy, copper zinc palladium non precious nickel and zircon. Platform 2 being patient specific, provides improved surface area contact between teeth and retainer platform 2. Platform 2 adapts closely to the rear surface contour or anatomy of the patient’s teeth as it is custom made to conform to an individual patient via each element of the platform conforming to each tooth in a teeth array to which the platform is attached. This intimacy of fit is without compromise to a flossing pathway, oral hygiene and access.

[0045] A dental adhesive glue / cement is preferably applied to the platform elements via an internal space within each platform to adhere the platform and each element to teeth opposing the respective elements. The adhesive glue is not applied in the spaces where the platform elements join ( refer joins 38, 39, 40, 41 and 42 in figure2) . Upon setting / curing of the adhesive glue; the practitioner cuts retaining arms 15 and 16 from the platform 2 to release the setting jig 3. The positioning handle 13 is used to remove jig 3, following which the retainer 2 is machined with a bur to remove any rough abrasive parts of the surfaces which could create patient discomfort, particularly to the tongue.

[0046] Figure 6 shows a schematic illustration of the geometry of a retainer element in elevation and its configurational relationship to a tooth according to one embodiment. In figure 6, tooth 60 is defined by various dimensions. Dimension A-B represents the height of the element 61. Dimension C-D represents the height of tooth 60. Dimension E-F defines width of element 61 and dimension G-H defines a width of tooth 60.

[0047] The configuration of element 61 relative to the size and shape of tooth 60 can vary from patient to patient and also according to patient specific characteristics which can be built into the assembly design. Accordingly, variations may be made to the size relationships between an element and its opposing tooth according to particular patient requirements. For example, the length ratio between length A - B and length C to D is preferably within the rage of 25-40%. Preferably, the length ratio between length E-F and length G-H is preferably within the rage of 40-60%. In another embodiment a ratio of opening size in an element if preferably within the rage of 50-70% of the diameter of theouter diameter of the body of the retaining element. Ring. It will be appreciated by persons skilled in the art that variations to this ratio are contemplated. Preferably the thickness of the ring is 0.75mm Platform thickness is preferably within the range 0.2-2mm.

[0048] Figure 7 shows a schematic illustration of a teeth array 65, 66, 67, 68, 69, 70 with a plurality of teeth engaging elements 71, 72, 73, 74, 75, 76, of different configurations. Tooth engaging retaining element 71 -76 each comprises a generally circular body which defines a circular internal space. Elements 71-76 may be adapted with extensions and / or recesses or voids. The geometry of each void may be the same for each element 71-76 or each element may vary according to design prescription. In figure 7, tooth engaging retaining element 71 comprises a generally circular body which defines a circular internal space and external extensions 77 and 78. Element 72 of tooth 66 includes voids 79 and 80 and extension 81. Element 73 is shown with two reciprocal radial voids 82 and 83. Element 74 includes two reciprocal radial voids 84 and 85 and an extension 86. Element 75 includes two reciprocal radial voids 87 and 88 in an alternative orientation off the horizontal and an extension 89. Element 76 includes three radial extensions 90, 91 and 92.

[0044] The internal voids described may be any shape and oriented in any radial direction, The external extensions can be located at any selected / designed radial location about the periphery of an element.

[0049] Figure 8 shows a schematic illustration of a teeth array including teeth 100, 102, 103 104, with a plurality of alternative teeth engaging elements 105, 106, 107, 108 each of alternative configurations.

[0050] These features of geometry are used to offset specific forces that potentially cause relapse. They can be employed to prevent vertical, rotational, transverse and angular relapse. Examples of shapes for the retainer elements include square, crescent, elliptical, semi circular, ovoid, polygonal, rectangular, star shaped. Example shapes are identified as 128 A- 128E which show hexagonal, rectangular, circular, rectangular and elliptical shapes. Element 105 includes a generally circular body defining an internal space 109 which is star shaped. Also included are voids 110 and 111 and extensions 112 and 113.

[0051] Element 106 includes a generally circular body defining an internal polygonal space 114. Also included are recesses or voids 115 and 116 and extension 117. Element 107 includes a generally circular body defining an internal circular space 118. Also included are a plurality of voids 119, 120, 121 and 122 and extension 123. Element 108 includes a generally circular body defining an internal space 124. Also included are extensions 125, 126 and 127. Figure 8 serves to illustrate the variety of retaining element configurations available for prescription depending upon patient specifics and design requirements.

[0052] Figure 9 shows a retainer assembly 130 including elements 129 131, 132, 133, 134 and 135 integrated with a setting jig 136 having a body 137 bridging between abutments 138 and 139 similar to the use and characteristics of setting jig 3 described earlier. Jig 136 is connected to platform 140 via retaining arms 141 and 142. and each including optional radial voids. Elements 129 131, 132, 133, 134 and 135 respectively include openings 143, 144, 145, 146, 147 and 148 which receive adhesive used when platform 140 is fitted to the back surfaces of a bottom front teeth array ( not shown but described earlier). Each said openings are configured to optimise fitting and adhesion to the particular tooth. Element 129 includes radial protrusions 149 which can increase surface area and bonding in that location. Opening 144 includes radial recesses 150 which provide additional contact areas for adhesive glue. Similarly opening 145 has radial recesses 151, opening 146 has radial recesses 152 and opening 147 includes radial recesses 153. Element 135 includes radial protrusions 154 similar to element 129.

[0053] Figure 10 shows a schematic illustration of an alternative embodiment of a platform a teeth array with a plurality of teeth 160, 161, 162, 163, 164, and 165 which respectively engage elements 166, 167, 168, 169, 170 and 171 defining a serpentine configuration. The serpentine configuration results in the formation of respective recesses 172, 173, 174, 175, 176 which in use, allow access for patient flossing when the retainer platform 178 is in situ.

[0054] Figure 11 shows a retainer assembly 180 comprising a setting jig 181 having a body 182 which spans between abutments 183 and 184 which as described earlier seat on molar teeth. Bridging body 182 of jig 180 are retaining arms 186 and 185 which support platform 187 formed by the plurality of elements 188, 189, 190, 191, 192 and 193. According to theembodiment of platform 187 shown, elements 188, 189, 190, 191, 192 and 193 are separated by serpentine recesses, 194, 195, 196, 197 and 198. As previously described by example with reference to the schematic layout of figure 10, the serpentine recesses 194, 195, 196, 197 and 198 of platform 187 allow access between teeth for cleaning and flossing.

[0055] Figure 12 shows a retainer assembly 200 according to an alternative embodiment. Assembly 200 comprises a setting jig 201 having a body 202 spanning between abutments 203 and 204. Abutment 203 includes underside formations 205 and 206 which are configured to seat on and preferably confirm to a patient’s molars as described previously. Likewise abutment 204 includes formations 207 and 208 which also conform to patent molars. Assembly 200 further comprises a platform 209 comprising elements 210, 211, 212, 213, 214 and 215, which in use oppose the rear back surface of an array of front teeth. Elements 210, 211, 212, 213, 214 and 215, respectively comprise openings 216, 217, 218, 219, 220 and 221. In this embodiment the openings are all substantially circular and provide access for a fixation adhesive. The elements having no additional extensions or recesses / voids as described for earlier embodiments. Platform 209 is joined via retaining arms 222 and 223. Once platform 209 is set in position and glued, retaining arms 222 and 223 are cut to release setting jig 201. As before any rough edges or protrusions are machined away to form a smooth surface avoiding any harm to a patient’s tongue.

[0056] It will be appreciated by those skilled in the art that numerous variations and modifications may be made to the invention without departing from the overall spirit and scope of the invention broadly described herein.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:1 An assembly for installation of a lingual retainer for correction of a teeth array; the assembly comprising; a platform formed from a plurality of elements for retaining teeth, each element capable of co -operating engagement with at least one adjacent element each element having a tooth engagement surface; a setting jig having a first end formation configured to seat on at least one tooth and a second end formation configured to seat on at least one tooth, the setting jig further comprising at least one retaining arm bridging between the setting jig and the platform to retain the platform in a predetermined attitude relative to the teeth when the jig is seated via the first and second end formations.2 An assembly according to claim 1 wherein, elements are integrally connected to said at least one adjacent element via an integral connection.3 An assembly according to claim 2 wherein elements are integrally connected to said at least one adjacent element via a fold in the platform.4 An assembly according to claim 3 wherein, each element of the platform opposes a tooth in the array of teeth while in said co operating engagement with said at least one adjacent element.5 An assembly according to claim 4 wherein each element and its tooth engagement surface are preformed6 An assembly according to claim 5 wherein the setting jig is connected to the platform via a plurality of retaining arms which bridge between the setting jig and platform.7 An assembly according to claim 6 wherein, the retaining arms extend radially from the setting jig to the platform.8 An assembly according to claim 7 wherein, the retaining arms bridge the setting jig and the platform at or near extremities of the platform.9 An assembly according to claim 8 wherein, the platform and setting jig are patient specific.10 An assembly according to claim 9 wherein, the platform is fixed to rear surfaces of front teeth using an adhesive.11 An assembly according to claim 10 wherein, each element of the platform has a central opening.12 An assembly according to claim 11 wherein, the central opening of each element is configured to receive said adhesive facilitating retention of the platform against an opposing tooth of the front teeth array.13 An assembly according to claim 12 wherein, each element has a circular outer circumference.14 An assembly according to claim 13 wherein, the configuration of the central opening in each element is selected from shapes including circular, star shaped, hexagonal, polygonal, square, triangular, rectangular, elliptical.15 An assembly according to claim 14 wherein at least one element of the platform has extending from the outer circumference at least one radially disposed protrusion.16 An assembly according to claim 15 wherein, at least one element has at least one recess extending radially from the central opening.17 An assembly according to claim 16 wherein, the assembly further comprises a holder including a handle which engages with and allows retention of the jig.18 An assembly according to claim 17 wherein, the handle enables setting of the jig via its abutments each on at least one molar tooth of a patient and setting of the platform against the array of teeth.19 An assembly according to claim 18 wherein, the molars are back teeth.20 An assembly according to claim 19 wherein, the array of teeth comprises front lower teeth21 An assembly according to claim 20 wherein, the retaining arms bridging the setting jig and platform are severable from the platform, bridges are severable from the platform22 An assembly according to claim 21 wherein, the handle facilitates removal of the setting jig once the retaining arms are severed.23 An assembly according to claim 22 wherein, the handle engages and retains the jig enabling seating of the platform intimately against the front teeth, for cementing using said adhesive.24 An assembly for installation of a lingual retainer against an array of teeth; the assembly comprising; a platform for retaining teeth formed from a plurality of co -operating elements, a setting jig having a first end configured to seat on a first supporting tooth and a second end configured to seat on a second supporting tooth, the setting jig further comprising at least one retaining arm which spans between the setting jig and platform to retain the platform in a predetermined attitude against the teeth in the teeth array, while confirming to teeth array contours; a handle which engages and retains the setting jig enabling a user to locate the platform against the teeth and remove the jig after installation of the platform.25 A setting jig for use with an assembly for the installation of a lingual retainer; the jig having a first abutment configured to seat on at least one tooth on a first side and a second abutment configured to seat on at least one tooth on an opposite side, the jig further comprising at least one retaining arm which spans between the abutments to retain a retaining platform in a predetermined attitude against and to conform to a surface of each of a plurality of teeth in the teeth array.26 A method for installation of a lingual retainer using an assembly comprising; a platform for retaining teeth formed from a plurality of elements, each element capable of co -operating engagement with at least one adjacent element via a connection, each element having a tooth engagement surface; a setting jig having a first end configured to seat on a first tooth and a second end configured to seat on a second tooth, the jig further comprising at least one retaining arm which spans between the jig and platform to retain the platform in a predetermined attitude; a positioning handle which engages and retains the setting jig enabling a user to locate the platform against the teeth; the method comprising the steps of . a) taking the positioning handle and placing the jig on supporting teeth and locating the platform against a surface of each tooth of a selected tooth array; b) applying dental glue to selected platform elements to adhere the platform and each element to teeth opposing said elements; c) upon setting of the glue; cutting retaining arms from the platform to release the jig; d) using the positioning handle to remove the jig; e) finishing the retainer by smoothing surfaces.

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