Teeth aligner system

Abstract

A method and apparatus providing orthodontic tooth movement (OTM) using a removable aligner, by providing a shaped removable aligner formed of a thermoplastic and moulded to an OTM fitting shape relative to the teeth of a patient; applying a layer of a gel to an inner surface of a teeth-receiving cavity of the thermoplastic aligner; locating the shaped removable aligner with the applied gel layer in a required OTM fitting position on the teeth of the patient to provide an effective OTM force on the teeth; wherein the gel layer substantially separates and spaces the aligner from the teeth while providing a force transfer mechanism from the aligner to the teeth.

Claims

1. A teeth aligner system providing orthodontic tooth movement (OTM) for use in assisting corrective realignment of a patient's teeth, the aligner system including: a. a removable thermoplastic aligner having a teeth receiving cavity with a teeth aligning surface formed as an inner surface of the teeth receiving cavity; b. a transparent force transfer layer formed on the teeth aligning surface comprising a curable gel engaging between the teeth aligning surface and the patient's teeth, enabling a separation and spacing of the aligner from the teeth while providing a force transfer mechanism from the removable thermoplastic aligner to the teeth when in located in a required OTM fitting position on the teeth of the patient to provide an effective OTM force on the teeth; c. wherein the curable gel and the thermoplastic of the aligner are selected to provide a comparative difference of adhesion bond between the cured gel and thermoplastic aligner and the cured gel and the patient's teeth allowing ready removal of the aligner without damage to the teeth and ready repositioning to the OTM fitting position. d. wherein a polysiloxane composition is applied to the teeth aligning surface of the removable thermoplastic aligner and allowed to partially cure so as to form an adhesive bond with the patient teeth surface, and wherein an opposite surface of the polysiloxane composition, allows comparative weaker adhesive bond to the patient's teeth surface, allowing preferential removing of the aligner from the teeth without removing tooth enamel, and e. wherein the teeth aligning surface includes a surface texture formed by an applicator as the polysiloxane composition is applied onto the teeth engaging surface of the removable thermoplastic aligner.

2. A teeth aligner system according to claim 1, wherein the gel, upon completed curing of the gel, forms a first bond with the thermoplastic of the teeth aligning surface of the aligner and a second bond with the enamel surface of the teeth of the patient.

3. A teeth aligner system according to claim 2 wherein the applicator is adapted to etch the surface of the removable thermoplastic aligner, wherein the surface texture is formed by a series of grooves wherein the grooves are effective for gripping a surface of the teeth when the removable thermoplastic aligner is worn by a patient.

4. A teeth aligner system according to claim 1, wherein the transfer layer conforms to the teeth location configuration of the aligner and provides effective cushioning of initial orthodontic realignment force while able to maintain a minimal force over time and multiple removal cycles effective for realignment of teeth.

5. A teeth aligner system according to claim 1, wherein the first and second bond formed between (i) the transfer layer and aligner and (ii) the transfer layer and teeth, respectively, allows retention of the aligner system on the wearer's teeth and removal of the aligner without damage to tooth enamel following removal of the aligner.

6. A teeth aligner system according to claim 1, wherein an upper surface of the gel layer opposite the lower surface provides an attachment surface for attachment to the teeth and allowing easy removal of the removable thermoplastic aligner from the wearer's teeth without detaching the gel from the removable thermoplastic aligner while minimising damage to tooth enamel during the removal process.

7. A teeth aligner system according to claim 1, wherein the clear gel is located between the teeth and the aligner to provide an advanced force transfer interface to the teeth.

8. A teeth aligner system according to claim 1, wherein the combination of the removable thermoplastic aligner and the gel layer are clear and the preferential adhesion of the gel layer to the thermos plastic aligner over the adhesion to the teeth allow damage-free removal from the teeth after use.

9. A teeth aligner system according to claim 8, wherein an effective differential adhesion bond strength can have the ratio of bond strength formed at the first interface formed between the aligner and the transparent force transfer layer and the second interface between the transparent force transfer layer and the patient's teeth of between about 3:1 to 10:1.

10. A teeth aligner system according to claim 1, wherein the inner surface of the gel layer and a textured surface portion of the removable thermoplastic aligner forms a mechanical and/or adhesive bond upon cross linking of the gel by curing of the gel and interconnecting with the textured surface portion.

11. A teeth aligner system according to claim 1, wherein a curved shaping and configuration of the removable thermoplastic aligner aids frictional attachment to the teeth.

12. A teeth aligner system according to claim 1, wherein the gel layer composition of the invention provides a differential adhesion strength between a first interface formed between a textured surface of the removable thermoplastic aligner and the gel layer, and a second interface between the gel layer and the patient's teeth.

13. A teeth aligner system according to claim 1, wherein the removable thermoplastic aligner is formed of a plastic material so as to enhance an effective differential adhesion bond strength of a first interface formed between the thermoplastic aligner aligner and the oral adhesive so as to be greater than a second interface between the oral adhesive and the patient's teeth wherein the aligner is more readily removed with the oral adhesive from the patient's teeth.

14. A teeth aligner system according to claim 1, wherein an effective differential adhesion bond strength is such that a first interface formed between the aligner and the transparent force transfer layer is greater than a second interface between the oral adhesive and the patient's teeth wherein the aligner is more readily removed with the gel layer from the patient's teeth.

15. A teeth aligner system according to claim 1, wherein an effective differential adhesion bond strength is provided by scoring the textured portion of the teeth contacting surface of the removable thermoplastic aligner to increase the adhesive bond of first interface of the gel layer to the removable thermoplastic aligner and enable the lesser bond strength at the second interface between the gel layer and the patient's teeth allowing the aligner to be fitted to and effective for realignment of teeth, and removed from teeth without damaging teeth enamel.

16. A teeth aligner system according to claim 1, wherein the gel layer is formed from a polysiloxane selected from compounds having the general formula below: ##STR00007## wherein R1, R2 and R5 and R6 can be an alkyl group or a phenyl group; wherein R3 and R4 can be selected from alkyl groups and vinyl groups; and wherein R7 and R8 can be selected from alkyl groups and vinyl groups.

17. A teeth aligner system according to claim 1, wherein the gel layer further includes a range of agents selected from calcium salts, bioactive glass, antibacterials, probacterials, and wherein said one or more of selected agents is dispersed in the polysiloxane matrix and able to diffuse through the matrix for absorption.

18. A teeth aligner system according to claim 1 further including an applicator for providing a constant thickness layer of gel over the teeth aligning surface formed as the inner surface of the teeth receiving cavity.

19. A teeth aligner system providing orthodontic tooth movement (OTM) for use in assisting corrective realignment of a patient's teeth, the aligner system including: a. a removable thermoplastic aligner having a teeth receiving cavity with a teeth aligning surface formed as an inner surface of the teeth receiving cavity; b. a transparent force transfer layer formed on the teeth aligning surface comprising a curable gel engaging between the teeth aligning surface and the patient's teeth, enabling a separation and spacing of the aligner from the teeth while providing a force transfer mechanism from the removable thermoplastic aligner to the teeth when in located in a required OTM fitting position on the teeth of the patient to provide an effective OTM force on the teeth: c. wherein the curable gel and the thermoplastic of the aligner are selected to provide a comparative difference of adhesion bond between the cured gel and thermoplastic aligner and the cured gel and the patient's teeth allowing ready removal of the aligner without damage to the teeth and ready repositioning to the OTM fitting position; d. an applicator for providing a constant thickness layer of gel over the teeth aligning surface formed as the inner surface of the teeth receiving cavity; and e. a heat generating system for providing heat source to increase to the heat affected gel curing rate.

20. A teeth aligner system according to claim 19 wherein the heat generating system is incorporated in the applicator.

21. A teeth aligner system providing orthodontic tooth movement (OTM) for use in assisting corrective realignment of a patient's teeth, the aligner system including: a. a removable thermoplastic aligner having a teeth receiving cavity with a teeth aligning surface formed as an inner surface of the teeth receiving cavity; b. a transparent force transfer layer formed on the teeth aligning surface comprising a curable gel engaging between the teeth aligning surface and the patient's teeth, enabling a separation and spacing of the aligner from the teeth while providing a force transfer mechanism from the removable thermoplastic aligner to the teeth when in located in a required OTM fitting position on the teeth of the patient to provide an effective OTM force on the teeth; c. wherein the curable gel and the thermoplastic of the aligner are selected to provide a comparative difference of adhesion bond between the cured gel and thermoplastic aligner and the cured gel and the patient's teeth allowing ready removal of the aligner without damage to the teeth and ready repositioning to the OTM fitting position; d. an applicator for providing a constant thickness layer of gel over the teeth aligning surface formed as the inner surface of the teeth receiving cavity; and wherein the applicator includes a scoring means and a delivery means; wherein the scoring means affects a top surface of the aligner to form a textured surface in advance of the gel and wherein the delivery means stores and delivers a quantity of the gel to the inner surface of the teeth receiving cavity.

22. A teeth aligner system according to claim 21 wherein the applicator comprises a sponge tip on or adjacent the delivery end of a barrel, the sponge tip being movable relative to or over the delivery end during egress of the gel composition, wherein during delivery of the gel composition onto a surface of the aligner, the sponge tip applies microscopic score lines or textured surface to a surface of the dental straightening device, and wherein the scored or textured surface is adapted to allow preferential mechanical adherence of the gel layer to the dental straightening device.

23. A teeth aligner system according to claim 22, wherein the sponge tip is selected from a range of polymeric materials including polyether, polyvinyl alcohol, or polyester, and a collection of bioglass particles.

24. An applicator for applying a textured surface to and delivery of a gel composition to a thermoplastic teeth aligner, the applicator comprising: i. a storage compartment for containing the gel composition, and a delivery end, wherein the gel composition includes a polysiloxane and catalyst in a predetermined ratio, ii. a sponge tip on or adjacent the delivery end of a barrel, the sponge tip being movable relative to or over the delivery end during egress of the gel composition, iii. wherein during delivery of the gel composition onto a surface of the thermoplastic teeth aligner, the sponge tip applies microscopic score lines or textured surface to a surface of the dental straightening device, and iv. wherein the scored or textured surface is adapted to allow preferential mechanical adherence of the gel layer to the thermoplastic teeth aligner.

Description

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

(1) FIG. 1: provides a plan schematic representation of dental surfaces of teeth in the mandible;

(2) FIG. 2: provides schematic plan view of a teeth aligner system for use in the present invention;

(3) FIG. 3: provides a schematic vertical cross-section of the tooth across B-B of the aligner system of FIG. 2 in use in an embodiment of the invention;

(4) FIG. 4: is a graphical representation of force versus time characteristics of a continuous interrupted orthodontic tooth movement (OTM);

(5) FIG. 5: is a diagrammatic flow diagram of a method of preparing an aligner system in accordance with an embodiment of the invention;

(6) FIG. 6A: is a diagrammatic front view representation of an applicator system for storing, mixing and delivering a curable gel composition to an aligner for forming a gel layer on the aligner in accordance with an embodiment of the invention;

(7) FIG. 6B: is a diagrammatic rear view representation of an applicator system for storing, mixing and delivering a curable gel composition to an aligner for forming a gel layer on the aligner in accordance with an embodiment of the invention;

(8) FIG. 7A: is a diagrammatic of a gel applicator in chisel shape for applying a layer of curable gel to aligner useable with the applicator system of FIG. 6 in accordance with an embodiment of the invention;

(9) FIG. 7B: is a diagrammatic view of a gel applicator in pencil shape for applying a layer of curable gel to aligner useable with the applicator system of FIG. 6 in accordance with an embodiment of the invention;

(10) FIG. 8: is a graphical representation of temperature increase versus time for different CaCl.sub.2; water; CMC masses in which different mass ratios of calcium chloride obtained different temperature increases, of 27é C, 36é C and 40é C for 1 g:1 g, 2 g:2 g and 3 g:3 g of calcium chloride:water, respectively so that room temperature water at 25é C, the 1:1, 2:2 and 3:3 mass ratios are able to obtain 52é C, 61é C and 65é C of heat, respectively with the peak temperature occurred at the 1 minute mark, then slowly decreasing over time;

(11) FIG. 9: is a diagrammatic side view of a CaCl.sub.2 and water applicator in accordance with an embodiment of the invention for applying the curable gel composition to an aligner for forming a gel layer on the aligner in accordance with an embodiment of the invention;

(12) FIG. 10: is a diagrammatic flow diagram showing steps for speeding curing of force transfer gel composition with a heat generating system in accordance with an embodiment of the invention;

(13) FIG. 11A: is a front view of an alternative applicator design with front view showing chambers for maintaining first and second components of gel separate until in use and applicator slot, in accordance with an embodiment of the invention;

(14) FIG. 11B: is a back view of the alternative applicator design of FIG. 11A with back view showing chambers for maintaining CaCl.sub.2 and water separate until combined to allow dissolution as a heat generating means system for speeding curing of force transfer gel composition in accordance with an embodiment of the invention;

(15) FIG. 12: is a flow diagram of steps for combining and setting components of the gel and with selective extent of curing of force transfer gel composition in steps external to oral cavity and in-situ formation accordance with an embodiment of the invention;

(16) FIG. 13 show graphical results of force transfer exerted by aligner system of the invention with time on front teeth surfaces using a first aligner of C+ type with 0.77 grams of gel forming gel layer versus control aligner without gel layer;

(17) FIG. 14 show graphical results of force transfer exerted by aligner system of the invention with time rear teeth surfaces using a first aligner of C+ type with 0.77 grams of gel forming gel layer versus control aligner without gel layer;

(18) FIG. 15 shows graphical results of force transfer exerted by aligner system of the invention with time on front teeth surfaces using a first aligner of ACE type with 1.14 grams of gel forming gel layer versus control aligner without gel layer;

(19) FIG. 16 shows graphical results of force transfer exerted by aligner system of the invention with time on front teeth surfaces and rear teeth surfaces using a first aligner of ACE type with 1.14 grams of gel forming gel layer versus control aligner without gel layer;

(20) FIG. 17 shows graphical results of force transfer exerted by aligner system of the invention with time on front teeth surfaces using a first aligner of ESSIX PLUS type with 0.97 grams of gel forming gel layer versus control aligner without gel layer;

(21) FIG. 18 shows graphical results of force transfer exerted by aligner system of the invention with time on front teeth surfaces and rear teeth surfaces using a first aligner of ESSIX PLUS type with 0.97 grams of gel forming gel layer versus control aligner without gel layer;

(22) FIG. 19: are graphical results of calibrated data of FIGS. 17 and 18 with force exerted by aligner system of ESSIX PLUS type for use in an embodiment of the invention with time on front and back teeth surfaces using a first aligner versus control aligner;

(23) FIG. 20: are graphical experimental results showing pull out force with reference to time from a mock jaw using a conventional aligner (no force transfer layer) and no gel;

(24) FIG. 21: are graphical experimental results showing pull out force with reference to time from a mock jaw using aligner system with the gel layer in accordance with an embodiment of the invention;

(25) FIG. 22 shows graphical experimental results showing force over 70 cycles of in use and removal and refitting into OTM position in the patient of the ESSIX PLUS type of aligners with gel layer showing the maintaining of effective force transfer to maintain cyclic OTM force in use;

(26) FIG. 23 shows graphical experimental results showing force over 70 cycles of in use and removal and refitting into OTM position in the patient of the ESSIX C+ type of aligners with gel layer showing the maintaining of effective force transfer to maintain cyclic OTM force in use;

(27) FIG. 24 shows graphical experimental results showing force over 70 cycles of in use and removal and refitting into OTM position in the patient of the ESSIX ACE type of aligners with gel layer showing the maintaining of effective force transfer to maintain cyclic OTM force in use;

(28) FIG. 25: is a graphical representation of comparative pull out force with time from a mock jaw using three types of aligners in an aligner system without gel, with gel layer in accordance with an embodiment of the invention, with only saliva and with conventional aligner;

(29) FIG. 26: is a graphical representation of comparative preferential adhesion to test surfaces of aligner as against adhesion to the teeth for variety of test groups including no gel where there is no adhesion at all, with gel in accordance with an embodiment of the invention showing effective preferential difference; with saliva showing the total lack of effective contact with the teeth, and inclusion of bioglass scratching of the aligner and use with gel in accordance with an enhanced embodiment of the invention showing the substantial improvement of comparative adhesion.

DESCRIPTION OF PREFERRED EMBODIMENTS

(30) It is noted in the following description that like or the same reference numerals in different embodiments denote the same or similar features. The following examples further illustrate the various embodiments of the present invention. Neither these examples nor any of the foregoing disclosure is construed as limiting in any way the scope of the present invention. Unless otherwise indicated, all parts and percentages are by weight.

(31) Referring to FIGS. 1, 2 and 3, there is shown an aligner system 21 comprising a substantially transparent removable thermoplastic aligner 22 which is configured to assist alignment of teeth 11 of a patient when in use in undergoing OTM treatment. The removable aligner 22 has a teeth-engaging recess 24 between a front part 22 and a rear part 23 for receiving the teeth 11 of the patient.

(32) The aligner is structured to give a greater front force on the front of the teeth 11 relative to the back force on the rear of the teeth in order to provide an OTM effective force on the teeth 11.

(33) However, the system includes a force transfer means in the form of a gel layer 31 that is comparatively more preferentially attached to the inner surface 23 of the aligner than to the teeth 11. This comparative adhesion is enhanced by the inner surface 23 being a textured surface formed by various methods. One group of methods occurs after construction of the aligner such as use by scouring and particularly using bioglass to scour. Another group of methods is during construction of the aligner such as use by forming peaks and troughs in the mould of the inner surface or horizontal moulded lines etc.

(34) A suitable inner surface 25 is the textured surface forms on which a force transfer gel layer 31 is securely attached. In use, the recess 24 of the dental aligner 22 receives teeth 11 such that the force transfer layer 31 and the aligner 22 is retained cyclically by frictional fit while preferentially being retained adhesively on the aligner 22. The bond between the gel layer 31 and dental aligner is greater than the attachment of the gel with the teeth forming a differential so that the gel layer allows the brace to be removed by peeling away from the teeth without removal of the gel from the aligner, and without removing or minimal effect on tooth enamel.

(35) FIG. 5 illustrates a method of preparing an aligner system in accordance with an embodiment of the invention. At step 101, the aligner shaped based on the patient's teeth is provided. At step 102, gel component A and gel component B, when combined is configured to provide a gel which provides the force transfer gel layer 31. At step 103, the gel is applied to the aligner at a desired temperature such as around room temperature. At step 104, the aligner is inserted into and positioned within the mouth of the user by the orthodontist. At step 105, the aligner with gel is allowed to set over time and allowed to be removed after the treatment period is over.

(36) Referring to FIG. 7 FIG. 6A showing a front view (A) and FIG. 6B showing a back view (B) , there is shown a gel applicator 200 for applying a curable gel composition 31 to a teeth-engaging surface 25 of a dental straightening appliance 22. The applicator 200 can comprise a syringe barrel body providing a reservoir including two chambers 210, 220 separated by a divider. The chambers 210, 220 receive a predetermined amount of a curable polysiloxane gel composition base and a catalyst. The applicator further includes a mixing chamber 280 at one end of the reservoir, and a drive mechanism being a plunger at the opposite end of the reservoir for driving the curable gel composition base and a catalyst from the chambers to the mixing chamber.

(37) As shown, the applicator further includes a dispensing end including a sponge (not shown) adjacent the mixing chamber and a scoring means made from bio-glass forming a tip.

(38) As shown, in use the plunger promotes displacement of the gel and catalyst towards the mixing chamber for combining, and combined gel/catalyst is urged through the sponge for egress through the tip. During dispensing, the applicator is moved over the dental straightening appliance such that the scoring means contacts the surface of the dental straightening appliance in advance of gel front as the gel is liberated, to form a textured surface for adherence of the gel.

Example 1

(39) In use, an orthodontist creates and shapes a set of customized removable thermoplastic aligners for a patient. Once these aligners are formed, a force transfer layer is formed by brushing a gel onto the inner surface of each aligner (e.g. using points of a gel applicator) and inserted onto the teeth.

(40) Generally, there are several characteristics that occur: 1. The composition and properties of saliva does not significantly affect the ability of the gel to attach to the tooth enamel. 2. After setting at the room temperature such as the intraoral temperature of 37 C the following variations of temperature of 4ł C to 55ł C in situ due to hot or cold food or drinks does not significantly affect gel de-bonding

(41) Application of Gel to Aligner Interface a) The gel is to be applied to the aligner. It also allows incubate of the gel to ensure it is dry before applying loads etc.

(42) Materials: a) Gel interface (Silpuran 2403 of Wacker AG) b) ‘Points.sub.— disposable brush gel applicators (1) c) Disposable dental mixing pots (2) d) 1 ml syringe (3)

(43) Procedure: 1. Using 1 ml syringes, take even parts of A and B and place in mixing pot. 2. Stir for 30 seconds using a point 3. Take the mix up in a syringe and turn upside down. Wait until all bubbles have settled to the top and push in syringe until gel begins to come out 4. Empty syringe into a pot 5. Dip the point into the gel and apply a thin layer to the aligner 6. Insert into patient 7. Allow to set.

(44) This procedure for producing an aligner system of the invention allows forming of a first bond between the removable aligner and force transfer layer and a second bond between the force transfer layer and teeth, wherein the bond differential at the interfaces with the aligner and teeth are such that the force transfer layer will be preferentially retained by the aligner.

Example 2

(45) In another example using the applicator of FIGS. 6 and 7, after the orthodontist creates and shapes a set of customized liners for the patient, the aligners must have the gel brushed evenly in a thin layer of a predetermined thickness onto the inside surfaces of the aligner and then inserted into the patient.

(46) Under ambient temperature conditions, the time taken for curing of the gel composition is substantial. To speed up the time of curing and therefore the time that the patient can feel comfortable that the aligner is fully fitted, a heat-generating method is used. In this case the method uses the chemical reaction of dissolution of calcium chloride to provide the heat source.

(47) At 55ł C it takes 3.3 times quicker to set the gel to an equivalent cure state than at 37é C, the human intraoral temperature.

(48) The completion of curing (cross linking) in situ (within the oral cavity) provides a bond strength between the force transfer layer of cured gel composition with the wearers teeth sufficient to remain on the teeth and transfer orthodontic force on the teeth from the aligner.

Example 3

(49) In the third example with reference to FIGS. 8, 9, 10 and 11 there is a different heat-generating method allowing the gel composition forming the force transfer layer, to set out of the location on the teeth of the patient.

(50) It is important for the sake of adhesion and teeth conformity that the gel composition must set with while on the teeth; otherwise, there will be a misfit if the gel cures completely before it is inserted onto the teeth.

(51) Hence, in this example the gel composition was mixed and placed in a hot water bath at 55é C for 14.5 minutes; and, was applied onto the aligners using the scaffold-tip applicator. The aligners were fit onto the teeth of the patient and left to set for another 30 minutes.

(52) It is evident that the gel composition almost immediately softens after being exposed to the heat-generating method; then undergoes rapid cure after about 6 minutes. In the soft state the gel can be rolled or shaped and then placed on the aligners rather than pasted onto the aligners.

(53) Aligners

(54) Clear, removable aligner systems are used to improve upon the limitations of fixed orthodontic appliances; but mainly for aesthetic reasons. The process involves generating impression scans of the patient's dentition, and a virtual three-dimensional Computer-Aided Design (CAD) and Computer-Aided Modelling (CAM) techniques to plan desired tooth movements and produce a set of fortnightly aligners. The aligners are designed to induce a maximum of 0.15 to 0.25 mm of tooth movement for each two-week period and are ideally worn for a minimum of 20 hours per day. The system has limited control over precise tooth movements; hence, it is complemented by attachment composites that are used as force transfer mediums for better tooth control.

(55) Aligners are either digitally or manually made. They are a series of clear transparent polyacrylic plastic ‘trays’. They can be made from patients ̆ dental moulds (either through poly vinyl siloxane (PVS) impressions or digital intra-oral scans). The series of aligners are custom-made to allow small increment of dental movement.

(56) Even though the patient usually changes to a new set of aligners every 2-4 weeks (depending on which systems), the clear aligners are usually removed daily and only worn at least 20 hours per day. The patient removes the aligners to eat, floss and brush. Patients may have to remove them while drinking hot beverages and/or beverages that contain milk or sugar.

(57) There is a potential space between the plastic aligners and the teeth. This space varies in different systems, around different teeth (incisors vs premolars vs molars), as well as different parts of the tooth (incisor edge vs maximum curvature vs gingival embrasure areas). If patients do not brush and floss their teeth well after each meal, and replaces the aligners on the teeth, there will be a marked increase in intra oral acidity, increasing the risks of dental decay and decalcification.

(58) The aligners are generally a form of an acrylic, usually of polypropylene or polyvinylchloride (PVC) material. The three examples used are from the EXXIS ù range and comprise the ‘ESSIX C+’, ‘ESSIX ACE’ and ‘ESSIX PLUS’. The C+ is formed primarily of Polypropylene, the ACE is formed of co-polyester of polyethylene terephthalate and the ESSIX plus is formed of an hybrid co-polyester.

(59) To date aligners do not include any material but often have attachments on the teeth and matching shapings on the inside of the aligner. Therefore, a strong frictional fit occurs with aligners but this can require extensive force to the teeth as you must directly engage the teeth with the aligner.

(60) Gel

(61) The present invention uses a clear polysiloxane gel composition which is located between the teeth and the aligner to provide an advanced force transfer interface to the teeth. The gel which is sometimes called a ‘biogel’ is named not that it must be biologically derived; but it has to be biocompatible to the oral tissues.

(62) The polysiloxane force transfer layer is a 2-paste system that is mixed when extruded in a ‘gun-mixing tip’ system. From the softer gel state, it then sets over about a minute in a combined chemical reaction accelerated with intra oral temperatures, into a semi solid state.

(63) The gel is applied thin enough to perpetuate the potential space and undercuts of the teeth between the teeth and the aligners. It has to be firm in order to withstand intra oral pressures and forces. It demonstrates minimal creep to allow an extended intra oral usage without constant replacement.

(64) As will be shown in tests described later the gel dampens the pressures and stresses that the original aligners have on the teeth prior the placement of the gel but may shrink slightly in dimension to enhance that force level. It is not too porous or permeable so as not to allow the blatant absorption of saliva and other liquids in the oral cavity. It does not ‘lock in’ the aligners and disallow simple removal of the aligners.

(65) The biogel is easily applied onto a clean and dry aligner using the custom-made dispenser tip. After the insertion of the aligners, any excess should be easily cleaned out from the gums and surrounding soft tissues using a cotton bud or tissues before the initial set of the gel. The biogel adheres to the aligner and not the teeth when the aligners are removed. It is easily peeled off (from the aligners) and discarded at the end of its use. It is substantially biodegradable.

(66) As the aligner system of the invention are worn all the time except eating and brushing, the biogel withstands an extended period of use. Ideally it is changed with every new aligner (2-4 weeks), but depending on dimensional changes and its ability to maintain consistent force levels over the test period, the biogel may need to be changed 2-3 times daily.

(67) The biogel allows a seamless connection between the aligners and the teeth, transferring the forces originally designed and intended by the manufacturers of the aligner systems.

(68) The aligner gel is applied using a syringe-type device that can accommodate a two-part gel component system that on mixing undergoes a cross linking-type reaction to yield a solid translucent film. This film functions to fill any gaps between aligner and teeth. Patient will typically wear aligner throughout the day and only require removing them for eating. The Aligner Gel will need to robust enough to withstand regular detachment/reattachment of the aligner/Aligner Gel composite device as required by the patient to follow their daily eating schedule.

(69) Patients will need to perform the Aligner Gel protocol each time a new aligner is fitted (currently˜every two weeks in accordance with the stepwise correction schedule dictated by the orthodontist/aligner manufacturer)

(70) The aligners are preferably formed of a plastic material so as to enhance the effective differential adhesion bond strength of the first interface formed between the aligner and the oral adhesive so as to be greater than second interface between the oral adhesive and the patient ̆s teeth wherein the aligner is more readily removed with the oral adhesive from the patient ̆s teeth.

(71) The Gel is more precisely called polymerized siloxanes or polysiloxanes, silicones are mixed inorganic-organic polymers with the chemical formula [R.sub.2SiO].sub.n, where R is an organic group such as methyl, ethyl, or phenyl. These materials consist of an inorganic silicon-oxygen backbone (-Si—O—Si—O—Si—O-) with organic side groups attached to the silicon atoms, which are four-coordinate.

(72) In some cases, organic side groups can be used to link two or more of these —Si—O— backbones together. By varying the —Si—O— chain lengths, side groups, and crosslinking, silicones can be synthesized with a wide variety of properties and compositions. They can vary in consistency from liquid to gel to rubber to hard plastic.

(73) In its uncured state, silicone rubber is a highly-adhesive gel or liquid. In order to convert to a solid, it must be cured, vulcanized, or catalyzed. This is normally carried out in a two-stage process at the point of manufacture into the desired shape, and then in a prolonged post-cure process. It can also be injection molded.

(74) Silicone rubber may be cured by a platinum-catalyzed cure system, as a condensation cure system. For platinum catalyzed cure system, the curing process can be accelerated by adding heat or pressure.

(75) In one preferred form, the Gel is the Silpuran 2430 medical-grade, which has parts A and B and includes a catalyst (usually platinum) built into the system (in component A) to enact a room temperature vulcanization (RTV-2), triggered by the mixing of the equal parts of A & B.

(76) There are 2 different types of RTV2 silicone rubbers: Addition cure systems which use platinum based catalyst. Condensation cure systems which use a tin based catalyst.

(77) Silicone Rubbers cured with either system have very similar properties but there are some differences which is why Addition Cure Silicone (Platinum Based) is preferred.

(78) The key differences and therefore the preference for an Addition Cure Silicone (Platinum Based) include: Low shrinkage, below 0.1% Marginally higher tensile strength Slightly tougher rubber Need for careful and accurate mixing Good abrasion resistance Can be accelerated using heat Tolerant to the addition of silicone fluid as a softener

(79) In use 5 ml of A and B Silpuran 2430 gel is used per mix. It amounts up to 0.8 g of gel used for each aligner. Initial mixing is done under 25ł C and took 2.5 hours to set. In a different example mixing was done under 37ł C and it took 1 hour to set.

(80) The gel thickness is determined by the potential space between the aligner and the cast model. All excess will be extruded and discarded. However, it is important to provide an even thickness layer of gel. Therefore, use of the applicator allows treatment of the aligner to improve coarseness and to also allow ready quantity and thickness control of applied gel.

(81) Applicator

(82) Referring to FIG. 7, one form of applicator has a chisel shaped tip. In another form, there is a pencil shaped tip. The applicators have a scaffold at the tip to scratch the aligner to encourage the gel to have physical adhesion to the aligner.

(83) Once the two components are mixed together in the mixing chamber, a sponge-tip applicator is used to apply the gel onto the aligners. An interconnective scaffold of 95% porosity from Biometic Pty. Ltd. is used as the sponge material due its high porosity and ability to remember its shape, allowing effective gel delivery.

(84) The gel needs to be applied as evenly as possible to allow a uniform cure time and gel function. A chisel-shaped sponge tip and a pencil-shaped sponge tip (FIG. 6) were investigated to observe the influences of the sponge shape on the application of the gel onto the aligners.

(85) The gel was more easily and evenly applied with the pencil-shaped tip for all the molar, premolar and canine-premolar sections. The flexibility of the scaffold allowed the pencil-shaped tip to fit into the smaller areas of canine-premolar sections;

(86) However, the pencil-shaped tip was still too big to fit nicely into the incisor sections. The incisor sections of the aligner are more easily applied with the chisel-shaped tip solely due to its smaller width of the tip allowing the sponge to fit into the aligners.

(87) It is more difficult to control the amount of gel present on the scaffold-tip. The pencil-shaped tip stores a greater volume of gel upon first application of the 1 mL, with minimal need of re-application and applies enough gel onto the convex areas of the aligners.

(88) When using a heat generating system of dissolution of calcium chloride (as described further in later section), to minimise risks of calcium chloride reacting, the design of applicator with the calcium chloride and water chambers are separate from each other.

(89) As shown in an enhanced embodiment of FIG. 11Figures 11A and 11B the design of the applicator (400) consists of two faces: front and back. The front face contains three chambers: two gel chambers (410, 420) and one slot to hold the sponge-tip applicator (450); and the back face contains two chambers: one chamber (430) for calcium chloride flakes and one chamber for thickened water (440). The coinciding surfaces of the front and back faces are fully sealed so that neither components of front nor back chambers leak into chambers on the other face. The back face is designed to generate and deliver heat to the lower gel chamber through calcium chloride dissolution.

(90) In use, as the gel in the upper chamber is pushed into the gel in the lower chamber, the calcium chloride will also be pushed into the water chamber to induce a dissolution reaction, generating heat. A sponge tip applicator will then be soaked with uniformly mixed gel and evenly coat the inner linings of the aligners for the patient to wear.

(91) A huge advantage of this applicator is that it is disposable and is very simple to use. As a result, it is hygienic, which is important as a medical product. The product is also very small, and the laminate/foil pouches used to make the chambers are readily available at low cost.

(92) TABLE-US-00001 No. Requirement Description Rationale Uniform Property 1.1 Gel parts shall be mixed Gel interface must exhibit uniform property thoroughly throughout. Biocompatibility 1.2 Gel and activating materials shall Gel must not be harmful to the patient both be biocompatible. locally and systematically. Aesthetics 1.3 Gel shall be clear. Gel system must be visibly superior over attachments of the Invisalign system. Applicator Function 1.4 Gel can be easily applied with the Gel should be evenly and easily applied with applicator. an applicator. 1.5 Applicator shall be capable of Gel cure time must be shortened for the achieving the temperature aligners to be inserted shortly after gel required to accelerate gel cure application. time. Shelf Life 1.6 Gel shall have a reasonable shelf Gel must have a reasonable minimum shelf life. life to support the duration of treatment. Gel Adhesion 1.7 Gel must preferentially adhere to Gel mast remain attached on the aligners to the aligners than to the tooth. avoid patient discomfort and loss of gel volume upon insertion-removal cycles. 1.8 Aligners with gel can be easily Gel interface system must not adhere to the removed. teeth too strongly that it prevents aligner removal. Bond Strength 2.1 Gel function shall remain Water/saliva can reduce the frictional forces constant upon contact with saliva. between the polymer chains, reducing the mechanical properties. 2.2 Gel shall not disintegrate at 37° C. Gel must withstand intraoral temperature. in the mouth. 2.3 Maximum gel retention pull force Gel shall exhibit greater retention to aligners must be greater than 17N. than with aligners with attachments. Fatigue Resistance 2.4 Gel shall not disintegrate upon 70 Gel interface system with clear aligners are to insertion-removal cycles. be used by the patient for multiple 2 week periods. Force Transferability 2.5 Gel volume shall remain at an Gel volume should not be lost between appropriate level for triggering insertion and removal cycles. orthodontic tooth movement 2.6 Initial force applied by the gel Gel shall serve as a more consistent force shall not plateau after day 1. transfer interface than Invisalign with attachment composites in which initial force quickly reaches plateau between day 2-14. 2.7 Gel shall provide at least 0.15- New gel interface system must provide tooth 0.25 mm of displacement per displacement that is at least as effective as the tooth. Invisalign system (maximum displacement of 0.15 to 0.25 mm per tooth).

(93) Benefits of System

(94) Gel formulation Setting time: How long does it take to set? Mechanical performance Ease of removal Minimal or no residual material on teeth post removal of aligner/gel device

(95) 1. Gel Benefits

(96) Benefits of Gel Include: Gel layer is clear Gel can set within a reasonable time period and only applied as much gel as is necessary Gel has adequate shelf life as it is a stable gel and ensure remains so with additives Gel can be easily applied with user friendly and simple applicator Gel can be removed from aligner easily after use as the applicator spreads gel evenly, and additives ensure ready removal Gel does not smell unpleasant during use as additives are used which neutralise odours Gel does not discolor over time as it is an appropriate gel type which does not absorb pigments Gel remains intact upon multiple insertions and removals as binding agent is used which ensures even thickness when applied to teeth Gel preferentially adheres to aligner upon removal as using appropriate silicone for adhesive properties. Potential for appropriate additives. Gel does not discolor with common food stuffs as use appropriate gel type which does not absorb pigments

(97) The polysiloxane curable gel used to form the force transfer layer overcomes the drawbacks of the prior art by avoiding propensity of aligners to stain or discolor by forming an intermediate layer. The gel layer therefore provides an aesthetic advantage over prior art removable thermoplastic aligners, which overcomes primary reasons for patient delays in using orthodontic measures for teeth realignment purposes.

(98) 2. Setting Time Benefits

(99) The temperature range at which the gel can be set in an adequate amount of time is of particular interest. The gel is to be applied onto the aligners and inserted into the mouth before it is completely set, to give it some time to set in shape with the dentition.

(100) Therefore, the cross-linking rate of a silicone formulation and its extent of reaction are important factors that determine its performance in a coating. For instance, the extent of cure strongly affects the release and adhesion properties of silicone. Moreover, temperature greatly affects the curing time of silicone. It has been demonstrated that the cross-linking reactions in polymers under various temperatures can be effectively investigated using a Scanning Vibrating Needle Curemeter.

(101) The human intraoral temperature, although usually at around 37é C, can spike up to 57é C upon consumption of hot food and drinks. In an investigation of the influences of temperature increases on the mechanical properties of thermoplastic aligners it has been found that the aligners effectively maintain its shape across the range of intraoral temperatures, but experiences a centralised stress above 56.5é C.

(102) The gel cure time must be accelerated for the patient to be able to wear the aligners soon after application of the gel. Higher temperatures will speed up the gel cure rate. With reference to FIG. 10, the devised heat-generating method shall aim to achieve a temperature range that is high enough to accelerate the cure time but low enough to avoid any detrimental changes to aligner properties.

(103) When using Silpuran A/B the cure times are as follows:

(104) TABLE-US-00002 Time in minutes Time in minutes % Cured at 37 łC. at 55 łC. 1 2.4 0.5 2 3 2 5 5 3.8 10 21 6.8 20 30 9.5 50 41 12.5 80 47 14.5 90 52.5 16.5 95 60 17.5

(105) Therefore, a heat-generating method is used to speed up the heat affected gel curing rate.

(106) In one form, the heat-generating method to speed up the heat affected gel curing rate uses calcium chloride. In another form, the heat-generating method to speed up the heat affected gel curing rate uses a hot water bath.

(107) The chemical ‘calcium chloride_ was chosen as it is used as a heat source and is also widely used as moisture absorbers. Further it also is used in purer food-grade forms.

(108) The molecular weight of anhydrous calcium chloride is 110.98 g/mol and 1 mol of pure calcium chloride exhibits a heat of enthalpy of −80 kJ/mol. Its characteristic to generate heat upon dissolution in water introduces some possibilities of it complementing the applicator system as a heat-generating component. By pure calculation, assuming that the heat capacity of water is 4.18 J/gé C, a 1:1 ratio of calcium chloride to water can raise the water temperature by 87é C. Similarly, 1:2 ratio can raise the temperature by 58é C and a 1:3 ratio can raise the temperature by 44é C.

(109) According to these results, calcium chloride dissolution is more than capable of generating enough heat to accelerate the gel set time. The quickness and effectiveness of heat generation by dissolution of calcium chloride is shown in FIG. 8.

(110) This system is therefore incorporated into one form of applicator as shown in FIG. 9. In this form, the design of the calcium chloride is with cough tablets in mind - sealed packets 310 that break as calcium chloride flakes are “pushed” into the water chamber 320 to activate the heat generating chemical process of dissolution of calcium chloride. By location of this chemical reaction next to but separate to the mixing of the gel components the mixed gel at a higher temperature can be applied by the applicator to the aligner and inserted onto the teeth of the patient to allow setting in situ.

(111) Controlling the setting time of the force transfer layer apart from significantly reducing fitting time for a patient, allows in-situ formation of an adhesion bond between teeth and curable gel layer of the aligner system. The extent of the adhesion bond between teeth and gel layer can be controlled by modifying the gel composition, however it is critical that there is an adhesion differential between the aligner and gel interface and teeth and gel interface to maintain retention bond to teeth in use, and allow preferential removal of the gel layer from the teeth upon removal of the aligner system with minimal enamel damage or residual gel layer on the teeth.

(112) In the enhanced form of FIG. 11 the dissolution of Calcium chloride is more readily achieved in a controlled and sealed manner to allow the heat treated combined gel components to form a gel layer with the applicator on the inner surface of the aligner and form the OTM force transfer means.

(113) With reference to FIG. 12, the gel is a heat curable material and is able to have the setting of the gel is undertaken for a predetermined time on the aligner external of the patient and the remaining setting of the gel in location in the OTM fitting position in the patient to provide the shaped form to correspond with the aligner and/or teeth of the patient to provide a minimalist thickness gel layer. At step 161 the gel components, A and B are provided. At step 162, the gel components A and B are combined to form a mixed gel. At step 163, heat generating means are positioned relative to the mixed gel to raise the temperature of the gel. At step 164, the gel mixture is greater than 50% cured. The curing of the mixed gel for the predetermined time on the aligner external of the patient during the setting period is greater than 50% but less than 85%. At step 165, the gel is allowed to fully set at a slower rate at a lower temperature. The shaping and spacing of the aligner from the teeth by the gel layer and the resilient nature of the gel layer allows for ready cyclic removal and insertion daily with effective replacement into OTM fitting position on the teeth of the patient.

(114) 3. Mechanical Performance—Force/Compression

(115) In orthodontics, forces are applied either continuously, continuously interrupted or intermittently. Traditionally, continuous forces have been incorporated to produce a constant mechanical stimulus on orthodontic appliances. These types of forces resorb alveolar bone and form new bone layers in the open marrow spaces in the periodontal ligament (PDL) tension sites at the termination of tooth movement. As a result, continuous forces are often regularly interrupted by the orthodontist to allow tissues the time for reorganisation in the PDL tension sites, ultimately triggering favourable tooth alignment Continuously interrupted forces appear to induce biologically favourable tooth movement due to its ability to quickly reduce force as the PDL hyalinises and cell necrosis occurs, supporting ideal paradental reconstruction with minimal tissue damage.

(116) FIGS. 13 to 19 illustrate the force vs time characteristic of continuous interrupted orthodontic force. It is intuitive that the declining force magnitude needs to be reactivated to its initial level with constant interruption in order to achieve ongoing satisfactory orthodontic tooth movement (OTM). As the gel is not solid, it expresses physical deformation as the aligners were inserted. Hence a ‘continued’ test allow its expression over time. This allowed us to study the force decay of the system; measuring the peak insertion force, and further normalising to a mean reading. Preliminary experiment had the gel set in-situ, the thickness of the gel affected the results. Subsequent experiment had the gel set with a clamp in place. This allowed an even thick layer standardised for all aligners.

(117) Traditionally, “light” orthodontic forces have been assumed to be more physiologically effective than “heavy” forces due to their ability to increase cellular activity and prepare tissues for further changes without causing unnecessary tissue compression. On the other hand, heavy forces can often cause hyalinisation of PDL, triggering root resorption.

(118) Other studies have developed a more detailed relationship between the magnitude of the applied force and the extent of tissue reaction. Iwasaki et al. [42] suggest that all forces above a certain threshold results in the same rate of tooth movement. Hixon et al. [43] suggest that after a certain threshold, higher forces are more efficient in tooth movement. Others oppose this and suggest a differential theory, which describes a linear relationship between the rate of tooth movement and the magnitude of applied force up until a certain threshold, at which a further increase in force magnitude causes a steep decline in the remodelling rate. According to the theory, low forces should be used for space closure as higher forces induce PDL hyalinisation and delay tooth movement. Another model shows that a plateau is reached after a certain threshold rather than a sharp decline.

(119) These findings highlight that there is no absolute relationship between the magnitude of applied orthodontic force and rate of tooth displacement, nor is there an absolute threshold of applied force that dictates the rate of tooth movement. Rather, different tooth movement will be reached within a broad range of forces.

(120) Referring to FIGS. 13 to 18, there is shown comparative applied force decay measurements on front and back teeth. The graphs identify terms F1.5 and B1.5.

(121) F: is the force moving the teeth forwards

(122) B: is the force moving the teeth backwards

(123) 1. When testing the aligner system comprising removable aligner and gel force transfer layer, the aligner system in a jig (see figure xx), peak force was less than the conventional aligner (without the gel layer) but maintained the force over 420 seconds—this proves the gel layer can be added without inhibiting the removable aligner and potentially promote the fatigue resistance of the aligner with time;

(124) 2. The gel liner in the aligners can help reduce the peak force at the beginning and keep the force until the end. This means at the beginning of a three-week surgery—the patient will experience less pain by using aligner with gel; and

(125) 3. The aligners with the gel had the same displacement as the aligners without gel and kept the force throughout the whole period.

(126) Again, for ESSIX PLUS, with gel layer one on backward tooth has higher force at the end compared to aligner (without gel).

(127) From a peak limit measured for the jig the gel liner consistently applied force to the end of the tooth displacement sequence—often being equivalent to or higher in force transferred by the no gel brace.

(128) With these observation, the gel liner in the aligners helps reduce the peak force at the beginning, and keep the force until the end. This means at the beginning of a three-week surgery, the patient will experience less pain by using aligner systems of the invention (with gel layer), and the aligner system continues apply force on the teeth after three weeks. The aligner system of the invention (with gel) can move the same displacement as the conventional aligner (without gel), and keep an orthodontic force throughout the whole period.

(129) For ESSIX ACE and ESSIX PLUS which shows higher force at the end, the gel on these aligners (around 1 gram) are thicker than the gel on ESSIX C+ aligner (0.8 gram). This means the force remains at the end may proportional to the thickness of the gel.

(130) TABLE-US-00003 Max force C+ ACE PLUS no gel 1 10.9 19.8 13.9 2 7 18.1 12.9 3 5.9 15.1 11.1 Average 7.933333 17.66667 12.63333 with gel 1 11.2 23.5 17.1 2 8.8 22.3 16.8 3 6.3 21.7 16.4 Average 8.766667 22.5 16.76667 with saliva 1 9.5 22.4 16.3 2 8.1 22 14.9 3 6.8 20.6 14.6 Average 8.133333 21.66667 15.26667

(131) These tables above and corresponding force decay results shown by graphs of FIGS. 13 to 18, confirms that the peak force for the aligner system of the invention is increased compared to conventional aligners but decreases relatively rapidly to a plateau force which is maintained for the length of the test. In essence therefore initial pain is quickly mitigated while effective force transfer occurs to provide the OTM force required and allow ready cyclic use by removal and replacement from and to an OTM position in the patient by the patient.

(132) Clearly, the aligner system with gel exhibits a varied initial and changing force than conventional aligner (without gel). The rapid decline from peak force to plateau force for the aligner system supports the view that the gel layer transfers a sufficient OTM force from the aligner but minimizes the length of time a patient is exposed to high/peak forces as a result of a compressive characteristic of the gel layer, i.e. the gel layer moves in-situ to adhere to the teeth and match the configuration of the aligner.

(133) Results from cycle testing (see FIGS. 22 to 24) shows force decay with 70 cycles of removal and insertion of the aligner system. As shown the force decay results indicate high (peak) initial force followed by consistent OTM force retention on teeth by the aligner system with 70 cycles.

(134) 4. Ease of Removal—Comparative Adhesion

(135) In this case, comparative adhesion refers to the preferential bonding of the gel to the one surface over another. This preference will most likely depend on the surface texture and wettability of the interfaces. If the gel is found to adhere to the teeth, this will be problematic to both the safety and efficacy of the device.

(136) In this study, samples of the gel interface were split into groups and placed upon the two different surfaces to be tested. The bonding strength between the gel interface and test surface will be measured quantitatively and qualitatively as well as being compared between groups. The silicone (Wacker AG ̆s Silpuran 2403) will be applied to the test surface and cured outside of the human mouth environment in order to mimic the conditions in which the proposed gel will be used by the patient in the market.

(137) The test of comparative adhesion looked at which surface, of the teeth or the aligner, the gel preferentially adheres. To show this comparative adhesion there were used 5 tests.

(138) Test 1: Conventional Aligner—No Gel Control Test

(139) Instron 5567 Universal Testing Machine was used to pull each aligner off the teeth in a direction perpendicular to the occlusal plane. The pull out force was recorded as the retentive force of the aligner; and, the pull out speed was set at 1 mm/s to investigate the worst case scenario of aligner removal. The test was repeated 3 times per test group and an average pull out force for each group was calculated.

(140) Test 2: Aligner System (with Gel Layer)

(141) The gel must set with the teeth; otherwise, there will be a misfit if the gel cures completely before it is inserted onto the teeth. Hence, the gel was mixed and placed in a hot water bath at 55é C for 14.5 minutes; and, was applied onto the aligners using the scaffold-tip applicator. The aligners were fit onto the matching mock jaw and was left to set for another 30 minutes before conducting the pull test.

(142) Pull out tests were conducted in an identical manner to Test 1. The removed gel-aligner set and the teeth surfaces were then visually inspected to record whether any gel residues were left on either of the test surfaces. The gel was mixed with a hint of red silicone pigment for ease of visual inspection.

(143) Test 3: Aligner System (with Gel Layer) and Saliva

(144) For the saliva groups, 1 mL of 37é C water was carefully spread over the teeth before the aligner with gel was fit.

(145) Gel preparation and application process, as well as the pull out test, were conducted in an identical manner to Tests 1 and 2.

(146) Test 4: Micro-Scratching (Gel and Saliva)

(147) Referring to FIG. 25, it is shown that in each removal test, a significant increased removal force is required for the aligner system compared to a conventional aligner. The greatest removal force was shown for etched bioglass aligner surface before application of the gel layer. Similar forces for removal were observed for composite gel layer including sintered sand.

(148) In summary table therefore the comparative adhesion to the aligner rather than the teeth is shown by Table below showing Pull-out adhesion parameters for mock jaw 1 aligners with gel:

(149) TABLE-US-00004 Average Adhesion Adhesion Mock max % increase/ to aligner to teeth Residue jaw 1 force (N) decrease (n/3) (n/3) area Essix 24.1 +6.6 1/1 1/1 Between C+ teeth, occlusal Essix 35.8 +23.9 3/3 2/3 Between ACE teeth, occlusal Essix 26.5 +7.3 3/3 2/3 Between PLUS teeth, occlusal

(150) In Table below of Pull-out adhesion parameters for mock jaw 2 aligners with gel .sup.- showing significant increase in pull out force for aligner system for each conventional aligner

(151) TABLE-US-00005 Average Adhesion Adhesion Mock max % increase/ to aligner to teeth Residue jaw 2 force (N) decrease (n/3) (n/3) area Essix 8.7 +10.1 3/3 1/3 Between C+ teeth, and occlusal Essix 22.5 +27.8 3/3 2/3 Between ACE teeth, and occlusal Essix 16.8 +33.3 3/3 2/3 Between PLUS teeth, and occlusal

(152) Table 15. Pull-out adhesion parameters for mock jaw 1 aligners with gel and saliva.sup.—showing significant increase in pull out force for aligner system for Essix ACE conventional aligner

(153) TABLE-US-00006 Average Adhesion Adhesion Mock max % increase/ to aligner to teeth Residue jaw 1 force (N) decrease (n/3) (n/3) surface Essix C+ 22.9 +1.3 3/3 0/3 N/A Essix ACE 31.4 +8.7 3/3 0/3 N/A Essix PLUS 24.3 −1.6 3/3 0/3 N/A

(154) Table 16. Pull-out adhesion parameters for mock jaw 2 aligners with gel and saliva.sup.—showing significant increase in pull out force for aligner system for each conventional aligner

(155) TABLE-US-00007 Average Adhesion Adhesion Mock max % increase/ to aligner to teeth Residue jaw 2 force (N) decrease (n/3) (n/3) surface Essix C+ 8.1 +2.5 3/3 0/3 N/A Essix ACE 21.7 +23.3 3/3 0/3 N/A Essix 15.3 +21.4 3/3 0/3 N/A PLUS

(156) Results shown in FIG. 26 show the following: 1. Equal adhesion for (i) gel layer and aligner, and (ii) gel layer and teeth .sup.—for gel layer comprising sintered sand composite gel; 2. 90% adhesion for gel layer and aligner, and 55% adhesion for gel layer and teeth .sup.—for aligner system 3. 100% adhesion for aligner and gel layer in presence of saliva; 4. 100% adhesion for aligner and gel layer, 10% adhesion to teeth .sup.—for bioglass etched aligner surface.

(157) The results of the adhesion tests show a desirable preferential adhesion between interface of gel layer and aligner and gel layer and teeth is achieved for the aligner system. This is achieved by controlling the first and second bond formed between the gel layer and aligner and gel layer and teeth, allowing removal of the aligner system without leaving gel layer on the teeth.

(158) However, this is also changeable depending on the components used in the gel layer and/or the nature of the aligner surface.

(159) 5. Minimal or No Residual Material on Teeth Post Removal of Aligner/Gel Interface

(160) This is shown by the experiments and supports that the use of the gel layer as a force transfer means allows ready OTM treatment while minimizing or nearly eliminating any surface damage to the teeth. It still allows ready cyclic removal and replacement to the OTM position by the patient in daily routines to allow cleaning of teeth.

(161) In Use

(162) The method of applying an aligner in a required temporary set position within the oral cavity of a patient the method includes the steps of: a. providing an aligner for use with a patient, wherein the aligner has a modified textured teeth-engaging surface; b. applying an oral gel layer to a surface of polymeric material of the aligner comprising an interior surface to receive at least a portion of one or more teeth of the patient when the aligner is worn; c. curing the curable adhesive, the curing comprising after the applying to the curable adhesive of a light source sufficient to cause the curable adhesive to cure to form a cured product bonded to the surface of the polymer material; d. the curable acrylic adhesive comprising: e. a polysiloxane is the aligner gel which is Silpuran 2430 which falls within compounds having the general formula 1 below

(163) ##STR00006## f. And an initiator.

(164) The aligner gel can include constituent components of calcium fortifier.

(165) The aligner gel can further include constituent components of an antibacterial agent.

(166) It can be seen that the invention of an aligner with gel layer provides the benefit of the gel being a mechanical-coupling interface between clear aligner systems and the teeth upon which they sit. The gel does not harbour unwanted bacteria is essential if the product is to be used safely in a patient ̆s mouth. The gel does not promote anomalous growth of select organisms in the patients ̆mouth.

(167) The gel layer is biocompatible to the oral tissues. It is preferably a two-paste system that is mixed when extruded in a ‘gun-mixing tip’ system. From the softer gel state, it then sets over about a minute in a combined chemical reaction accelerated with intra oral temperatures, into a semi solid state.

(168) The gel is thin enough to perpetuate the potential space and undercuts of the teeth between the teeth and the aligners. It is firm in order to withstand intra oral pressures and forces. The gel demonstrates minimal creep to allow an extended intra oral usage without constant replacement. It should not dampen the pressures and stresses that the original aligners have on the teeth prior the placement of the gel but may shrink slightly in dimension to enhance that force level. It should not be too porous or permeable to allow the blatant absorption of saliva and other liquids in the oral cavity. It should not ‘lock in’ the aligners and disallow simple removal of the aligners.

(169) The gel layer of the invention is easily applied onto a clean and dry aligner appliance using the custom-made dispenser tip. After the insertion of the aligners, any excess gel can be easily cleaned out from the gums and surrounding soft tissues using a cotton bud or tissues before the initial set of the gel. The biogel adheres to the aligner and not the teeth when the aligners are removed. It is easily peeled off (from the aligners) and discarded at the end of its use, and can be biodegradable.

(170) As the aligners are worn all the time except eating and brushing, the biogel withstands an extended period of use. It is changed with every new aligner (2-4 weeks), but depending on dimensional changes and its ability to maintain consistent force levels over the test period, the biogel may need to be changed 2-3 times daily.

(171) The gel layer of the invention allows a seamless connection between the aligners and the teeth, transferring the forces originally designed and intended by the manufacturers of the aligner systems.

(172) It negates the need for attachment placement completely. This improves the aesthetics of clear aligner systems, improves the patient experience with any clear aligner systems, decreases the chair time and costs of the clinician and prevents the damage to the enamel when the attachments are removed.

(173) The gel avoids hypersensitivity and allergic reactions.

(174) With prolonged aligner wear, the buffering effect of saliva neutralising the oral acids is reduced. This increases carious incidences and leads to higher chances of enamel decalcification. The biogel may be incorporated with a Fluoride releasing and/or tooth mousse CPAP calcium phosphorous remineralisation agent to negate that effect.

(175) Benefits of System

(176) It is clear there is a synergistic benefit in the combination of features

(177) These benefits include: Ideal aesthetics Removable Force application on all tooth surfaces Less pain responses Better oral hygiene

(178) Interpretation

EMBODIMENTS

(179) Reference throughout this specification to ‘one embodiment_ or ‘an embodiment_ means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases ‘in one embodiment_ or ‘in an embodiment_ in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

(180) Similarly it is appreciated that in the above description of example embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the Detailed Description of Specific Embodiments are hereby expressly incorporated into this Detailed Description of Specific Embodiments, with each claim standing on its own as a separate embodiment of this invention.

(181) Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

(182) Different Instances of Objects

(183) As used herein, unless otherwise specified the use of the ordinal adjectives ‘first_ , ‘second_ , ‘third_ , etc., to describe a common object, merely indicate that different instances of like objects are being referred to, and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner.

(184) Specific Details

(185) In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

(186) Terminology

(187) In describing the preferred embodiment of the invention illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar technical purpose. Terms such as “forward”, “rearward”, “radially”, “peripherally”, “upwardly”, “downwardly”, and the like are used as words of convenience to provide reference points and are not to be construed as limiting terms.

(188) Comprising and Including

(189) In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word ‘comprise_ or variations such as ‘comprises_ or ‘comprising_ are used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

(190) Any one of the terms: including or which includes or that includes as used herein is also an open term that also means including at least the elements/features that follow the term, but not excluding others. Thus, including is synonymous with and means comprising.

(191) Scope of Invention

(192) Thus, while there has been described what are believed to be the preferred embodiments of the invention, those skilled in the art will recognize that other and further modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such changes and modifications as fall within the scope of the invention. For example, any formulas given above are merely representative of procedures that may be used. Functionality may be added or deleted from the block diagrams and operations may be interchanged among functional blocks. Steps may be added or deleted to methods described within the scope of the present invention.

(193) Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

(194) Industrial Applicability

(195) It is apparent from the above, that the arrangements described are applicable to the dental, orthodontic and other specialist medical, dental and surgical industries.