WO2014008583A1

WO2014008583A1 - Method and system for orthodontic appliances

Info

Publication number: WO2014008583A1
Application number: PCT/CA2013/000632
Authority: WO
Inventors: Jean-Marc RETROUVEY
Original assignee: Retrouvey Jean-Marc
Priority date: 2012-07-13
Filing date: 2013-07-15
Publication date: 2014-01-16

Abstract

Whilst orthodontic appliances have achieved considerable popularity among the orthodontic community, patients compliance is difficult to achieve in many instances as these appliances have drawbacks including but not limited to comfort, retention, bulkiness, and aesthetics. Their main advantage over more sophisticated removable prosthesis to date has been their relative affordability and ease of fabrication. Accordingly it would be beneficial to provide orthodontic retainers which address these shortcomings in the prior art thereby increasing patient compliance. It would be further beneficial if such orthodontic retainers also addressed the cosmetic / aesthetic perceptions of patients with respect to the larger potential market relating to more cosmetic orthodontic treatments rather than those addressing more fundamental structural aspects of a patient's bite or other flaws of the teeth and jaw.

Description

METHOD AND SYSTEM FOR ORTHODONTIC APPLIANCES

FIELD OF THE INVENTION

[001] The present invention relates to removable orthodontic appliances and more particularly to those retained directly onto the undercut of the patient's teeth.

BACKGROUND OF THE INVENTION

[002] Orthodontics, from Greek orthos "straight or proper or perfect"; and odous "tooth", is a specialty of dentistry that is concerned with the study and treatment of malocclusions (improper bites), which may be a result of tooth irregularity, disproportionate jaw relationships, or both. Orthodontic treatment can focus on dental displacement only, or can deal with the control and modification of facial growth as well as being carried out for purely aesthetic reasons with regards to improving the general appearance of patients' teeth. In other situations orthodontic treatments are part of reconstructions ranging from partial facial reconstructions to full facial reconstructions.

[003] Removable orthodontic appliances have long been known and widely used leading to various types, some of which- date back to the early 20^th Century. Of the various orthodontic appliances orthodontic retainers, or simply retainers, are probably the best known. Orthodontic retainers are custom-made devices, normally fabricated on a stone dental cast, and are usually made of wire and plastic, e.g. acrylic, which hold teeth in position after an orthodontic treatment or are used during orthodontic procedures to perform minor tooth movements and alignments. They are most often used before minor tooth movement or after dental braces to hold teeth in position while assisting the adjustment of the surrounding gums to changes in the bone. Such dental braces typically being employed to correct the patient's bite for one or more issues including, but not limited to, underbites, malocclusions, overbites, cross bites, open bites, deep bites, crooked teeth, and various other flaws of the teeth and jaw.

[004] In order to maintain the orthodontic correction, most patients are required to wear their retainer(s) 24 hours a day initially with a gradual reduction to being at night only. There are four types of retainers typically prescribed by orthodontists and dentists, these being Hawley, vacuum formed (Essix), pressure formed (Zendura), and Bonded (Fixed) retainers.

[005] The best-known type is the Hawley retainer, which includes a metal wire that surrounds the teeth and keeps them in place. Named for its inventor, Dr. Charles Hawley, the labial wire, or Hawley bow, incorporates 2 omega loops for adjustment. It is anchored in an acrylic arch, for upper retainers this acrylic arch sits in the palate of the patient and in the floor of the mouth for lower retainers. The advantage of this type of retainer is their simplicity of fabrication and the possibility to add springs that finalize treatment and continue moving teeth as needed.

[006] In contrast the vacuum formed retainer (VFR or Essix retainer) employs a clear or transparent retainer that fits over the entire arch of teeth or only from canine to canine. A retainer, is produced from a mold of the patient's teeth. These are typically formed from polypropylene or polyvinylchloride (PVC) material approximately 0.025" thick wherein "Essix" is a brand name orthodontists are generally familiar with. VFRs do not allow the upper and lower teeth to touch because the plastic covers the chewing surfaces of the teeth and are typically removed for part of each day where orthodontists feel that it is important for the top and bottom chewing surfaces to meet to allow for a "favorable settling" to occur.

[007] Pressure formed retainers (Zendura) exploit Zendura material, a rigid polyurethane system optimized for superior stress retention properties, which by virtue of being a tougher material typically requires pressure molding in order to achieve good definition and fit for the retainer. Such retainers typically will illustrate better definition of gum line and gingival textures than VFRs. Fixed retainers typically consist of a passive wire bonded to the tongue- side of, usually depending on the patient's bite, only their lower incisors. They are typically prescribed where active orthodontic treatments have effected significant changes in the patient's bite and there is a high risk for reversal of these changes.

[008] Accordingly, orthodontic retainers within the prior art are defined by a plastic component frame in which stainless steel clasps of various sort are embedded or supplemental retention provided. Active springs or other active parts such as expansion screws have also been added to the plastic framework to selectively perform minor tooth movements. These appliances are fairly easy to fabricate, have proven to be efficient as orthodontic retainers, and are employed in approximately 2.8 million orthodontic case starts in the U.S. annually alone, of which 22 percent are adult and 78 percent are non-adult. Further, the American Association of Orthodontists estimates that there are approximately 24 million Americans currently prescribed to wear orthodontic retainers. However, the potential U.S. market is significantly larger than this as there are approximately 65 million potential patients who would like to improve their smiles, but would not seek traditional orthodontic treatment using wires and brackets.

[009] Accordingly, over the years there has been a significant amount of research and development for orthodontic devices including, but not limited to, the U.S. Patents and Patent Applications listed below. A significant fraction of the prior art is brace related, such as brackets for example, when compared to retainers but in areas such as modeling, acquisition, etc. considerable overlap exists in their application.

[0010] Retainer: 3,994,608; 4,609,349; 5,096,416; 5,536, 169; 5,607,300; 6,964,564; 2012/0,052,458; 2012/0,040,302; and 2002/0,098,460.

[0011] Wire Retainer: 4,725,230; 6, 135,767; and 7,703,482

[0012] Arch Wire or Wire: 4,386,909; and 2008/0,268,398.

[0013] Modeling: 6,318,994; 6,406,292; 6,602,070; 6,699,037; 6,729,876; 6,979, 196; 7,056, 1 15; 7, 1 10,594; 7,245,977; 7,273,367; 7,320,592; 7,331,783; 7,373,286; 7,433,810; 7,578,673; 7,826,646; 8,075,306; 8, 135,569 and 2004/0,072, 120.

[0014] Brackets: 3,597,845; 3,748,740; 3,772,787; 3,854,207; 4,243,387; 4,248,588; 5,224,858; 6,042,374; 6,247,923; 6,276,931 ; 7,121,825; 7, 125,248; 2005/0,019,720; and 2006/0, 199, 137.

[0015] Acquisition: 6,227,850; 6,386,867; 6,532,299; 6,592,371 ; 7, 142,312; 7,184,150; and 7,355,721.

[0016] Though such orthodontic appliances have achieved considerable popularity among the orthodontic community, patients compliance is difficult to achieve as these appliances have considerable shortcomings regarding, including but not limited to comfort, retention, bulkiness, and aesthetics. Their main advantage over more sophisticated removable prosthesis to date has been their relative affordability and ease of fabrication. Patient compliance is important as teeth move throughout life and accordingly maintaining the results obtained from lengthy and expensive orthodontic procedures such as for example orthodontic braces requires continued regular use of the orthodontic retainer by the patient.

[0017] Accordingly it would be beneficial to provide orthodontic retainers which address these shortcomings in the prior art thereby increasing patient compliance. It would be further beneficial if such orthodontic retainers also addressed the cosmetic / aesthetic perceptions of patients with respect to the larger potential market relating to more cosmetic orthodontic treatments rather than those addressing more fundamental structural aspects of a patient's bite or other flaws of the teeth and jaw.

[0018] Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.

SUMMARY OF THE INVENTION

[0019] It is an object of the present invention to address drawbacks in the prior art relating to removable orthodontic appliances and more particularly to those retained directly onto the undercut of the patient's teeth.

[0020] In accordance with an embodiment of the invention there is provided a method comprising retaining an orthodontic appliance within the mouth of a patient solely by engagement of a predetermined element of the orthodontic appliance with an undercut portion of a predetermined subset of the teeth of the patient.

[0021] In accordance with an embodiment of the invention there is provided a device a frame retaining the orthodontic appliance within the mouth of a patient solely by engagement of a predetermined element of the orthodontic appliance with an undercut portion of a predetermined subset of the teeth of the patient.

[0022] Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Embodiments of the present invention will now be described, by way of example only, with reference to the attached Figures, wherein:

[0024] Figure 1 depicts elements of orthodontic braces according to the prior art;

[0025] Figure 2 depicts an "invisible" orthodontic brace according to the prior art;

[0026] Figures 3A through 3C depict orthodontic retainers according to the prior art;

[0027] Figure 4 depicts patterned orthodontic retainers according to the prior art;

[0028] Figure 5A depicts an orthodontic wireframe retainer according to an embodiment of the invention; [0029] Figure 5B depicts a cross-section of a tooth indicating the region of undercut wherein an orthodontic wireframe retainer according to an embodiment of the invention is retained on the tooth;

[0030] Figure 6A depicts an orthodontic wireframe retainer according to an embodiment of the invention wherein the orthodontic retainer is provided on the exterior undercut of the patient's teeth;

[0031] Figure 6B depicts an orthodontic wireframe retainer according to an embodiment of the invention without a labial bow;

[0032] Figure 6C depicts an orthodontic wireframe retainer according to an embodiment of the invention;

[0033] Figure 7 depicts a 3D laser topography system for capturing orthodontic surface mapping data relating to a patient's teeth for implementing an orthodontic wireframe retainer according to an embodiment of the invention;

[0034] Figure 8 depicts an exemplary process flow for implementing an orthodontic appliance exploiting an orthodontic wireframe retainer according to an embodiment of the invention;

[0035] Figure 9 depicts an exemplary process flow for implementing an orthodontic appliance exploiting an orthodontic wireframe retainer according to an embodiment of the invention;

[0036] Figure 10 depicts orthodontic appliances of the prior art that may exploit an orthodontic wireframe retainer according to an embodiment of the invention;

[0037] Figure 1 1 depicts orthodontic appliances of the prior art that may exploit an orthodontic wireframe retainer according to an embodiment of the invention;

[0038] Figure 12 depicts orthodontic appliances of the prior art that may exploit an orthodontic wireframe retainer according to an embodiment of the invention;

[0039] Figure 13 depicts 3D digitized patient dental data and its processing by a software system executing software according to an embodiment of the invention to establish the undercut path for insertion of a wireframe retainer according to an embodiment of the invention;

[0040] Figure 14 depicts CAD image data relating to the patient showing the undercut path and clasps together with other clasps and ball clasps according to embodiments of the invention; [0041] Figure 15 depicts CAD image data of the wireframe retainer prior to data conversion for transmittal to a CAM system according to an embodiment of the invention;

[0042] Figure 16 depicts the addition of an undercut to a patient's tooth according to an embodiment of the invention;

[0043] Figure 17 depicts the addition of an undercut to a patient's tooth according to an embodiment of the invention.

DETAILED DESCRIPTION

[0044] The present invention is directed to removable orthodontic appliances and more particularly to those retained directly onto the undercut of the patient's teeth.

[0045] The ensuing description provides exemplary embodiment(s) only, and is not intended to limit the scope, applicability or configuration of the disclosure. Rather, the ensuing description of the exemplary embodiment(s) will provide those skilled in the art with an enabling description for implementing an exemplary embodiment. It being understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope as set forth in the appended claims.

[0046] Referring to Figure 1 there are depicted elements of orthodontic braces according to the prior art which are employed in adjusting the location of one or more teeth for a patient, typically in their childhood. As depicted these elements include:

• bracket - normally cemented directly onto the tooth for the purpose of attaching an arch wire;

• elastic tie - a tiny rubber band that fits around the bracket and holds the archwire in place;

• steel tie - thin piece of wire that is wrapped around the bracket to hold the archwire in place;

• wire or archwire - a metal wire attached to the brackets to move the teeth during treatment;

• elastic power chain - made of similar elastic material as elastic ties and in essence form a continuous band, from one tooth to another, and may be employed instead of the steel tie ligatures to increase the pressure applied during treatment;

• coil or coil spring - fits between brackets and over the arch wire to widen spaces between teeth; • rubber band post - a fitting on a bracket allowing attachment of a small rubber band that is attached to these posts and adds pressure to move the teeth;

• molar band - a thin metal ring, usually stainless steel, which serves to secure orthodontic attachments to a tooth; and

• headgear tube - round, hollow attachment where the inner bow of headgear external to the patient's mouth is inserted.

[0047] Accordingly, an orthodontist treating a patient to adjust the locations of a patient's teeth will typically attach molar bands to the patient's rear molars to anchor the braces to the patient's jaw. Accordingly, brackets are attached to the patient's teeth and the required expansion / tension elements including archwire, elastic power chain, coil, rubber band are employed to apply pressure to the teeth such that they move over a period of time. These braces are typically constructed from steel brackets and steel wire resulting in high visibility of the braces to others, a drawback of such braces to many individuals. Whilst brightly coloured brackets, elastic ties, etc. can provide some fun for children generally the visibility of braces becomes an increasingly significant issue for teens, young adults, and adults.

[0048] Hence within the prior art solutions to address this drawback have included the use of transparent "wires" and white ceramic brackets for example. Additionally, as depicted in Figure 2 depicts an "invisible" orthodontic brace according to the prior art wherein the brackets have been modified to fit the inner surfaces of the patent's teeth. However, whilst visual appearance drawbacks are reduced other issues such as comfort due to interference with the patients tongue and difficulty cleaning due to its being hidden are increased.

[0049] Accordingly it would be beneficial in some embodiments of braces to employ alternative means to engage the patient's teeth removing the bulky molar bands. It would also be beneficial to provide discrete or multiple anchor points for treatment without requiring that all or a substantial portion of the patient's teeth be cemented with brackets. Accordingly it would be beneficial in improving patient acceptance of brace type systems to provide a means for engaging the patient's teeth that minimizes the overall extent of orthodontic appliances within the patient's mouth, the number of attachments required to exterior surfaces of the patient's teeth, and the visibility of the orthodontic appliance.

[0050] Typically, post orthodontic treatment to adjust the position of one or more teeth of a patient the patient is required to employ an orthodontic retainer. Referring to Figures 3A through 3C there are depicted orthodontic retainers according to the prior art which comprise a series of wires embedded into a plastic body such that the wires loop between adjacent teeth and around in front. The pattern of these wires, as is evident in Figures 3A through 3C respectively, is established in dependence upon the specific requirements of each individual patient. The retainer accordingly is intended to minimize the subsequent drift of the adjusted teeth towards their original pre-treatment positions. The plastic body is designed to cover a substantial portion of the patient's upper palate, as evident in Figures 3 A and 3B, or a substantial portion of the lower gum and expose palate beneath the tongue for a lower retainer such as depicted in Figure 3C.

[0051] As with the orthodontic braces described above in respect of Figure 1 the plastic body of the orthodontic retainer may be patterned to make them more acceptable, particularly to children and teenagers. Examples of some patterned orthodontic retainers according to the prior art are depicted in Figure 4. However, such cosmetic effects do not fundamentally change the patient experience, especially the negative aspects including discomfort and cleanliness for example.

[0052] Referring to Figure 5 there is depicted an orthodontic wireframe retainer 500 according to an embodiment of the invention. Orthodontic wireframe retainer 500 comprises a plurality of profiled curls 530 which match the undercut profile of patient's teeth which are joined with teeth elements, such as first and second teeth 510 and 520 respectively, which fit the undercut of the adjacent teeth in the region between them. The orthodontic wireframe retainer 500 as depicted also includes molar loop 540 which fits around the undercut of the patient's molars and includes tooth 550 which matches the groove in the molar. Accordingly, the orthodontic wireframe retainer 500 has a profile that matches the undercut of the patient's teeth.

[0053] It would be evident to one skilled in the art that an orthodontic wireframe retainer according to an embodiment of the invention is retained within the undercut of the patient's teeth as evident from Figure 5B. As depicted in Figure 5B there is cross-section indicating the root, neck and crown portions of the tooth as normally defined within orthodontics. As evident in Figure 5B within the neck portion an undercut 590 exists wherein the tooth has narrowed and being approximately the region of the tooth wherein the gum (gingiva) and periodontium meet. Accordingly, insertion of the body 560 of the orthodontic wireframe retainer 500 into this region in retention of the body 560 against the tooth. Similarly, a second element of the orthodontic wireframe retainer 500 or a second wireframe retainer may be retained by similar insertion against the undercut with minor compression of the other gum 580.

[0054] Now referring to Figure 6A there is depicted an orthodontic wireframe retainer 610 according to an embodiment of the invention wherein the orthodontic wireframe retainer 610 is provided on the exterior undercut of the patient's teeth 620. As depicted orthodontic wireframe retainer 610 comprises a plurality of profiled curls 650 which match the undercut profile of patient's teeth which are joined with teeth elements, such as first and second teeth 630 and 640 respectively, which fit the undercut of the adjacent teeth in the region between them. The orthodontic wireframe retainer 610 as depicted also includes molar loop 670 which fits around the undercut of the patient's molars and includes tooth 660 which matches the outer groove in the molar. Accordingly, the orthodontic wireframe retainer 610 has a profile that matches the undercut of the patient's teeth.

[0055] Now referring to Figure 6B there is depicted an orthodontic wireframe upper retainer 680 according to an embodiment of the invention wherein a bow 690 has been included between the left and right sides of the orthodontic wireframe upper retainer 680 providing increased rigidity but without the full palate plastic plate of the prior art retainers. It would be evident to one skilled in the art that for an orthodontic wireframe lower retainer that a similar bow may be provided between the left and right hand sides but following a path along the lower part of the gum / mouth floor or under the tongue across the floor of the mouth. Referring to Figure 6C there is depicted an orthodontic wireframe retainer according to an embodiment of the invention.

[0056] As will be described below in respect of Figures 7 through 9 respectively orthodontic wireframe retainers, such as orthodontic wireframe retainers 500, 610, and 680 in Figures 5, 6A and 6B respectively, are based upon exploitation of Computer Aided Design (CAD) and Computer Aided Manufacturing (CAM) techniques wherein, for example 3D CAM orthodontic removable appliances according to embodiments of the invention are fabricated based upon processing within a CAD environment of data obtained from a 3D scan of an orthodontic dental cast obtained for example using a standardized impression technique, such as alginate material. Once the virtual dental cast of a patient has been digitized then it is "surveyed" upon a computer system to highlight the line of contour of the teeth and determine the optimum path of insertion for the orthodontic retainer according to embodiments of the invention. A wire frame and mesh are then designed to take advantage of the retentive part of the dentition, such as for example the undercut described in Figure 5B.

[0057] This virtual orthodontic appliance is then transformed in the actual orthodontic appliance by using CAD / CAM technology thereby allowing for a design / fabrication process that allows for the implementation of a highly retentive orthodontic appliance that does not require full palatal coverage.

[0058] Referring to Figure 7 there is depicted a 3D laser topography system 750 for capturing orthodontic surface mapping data supporting embodiments of the invention. The surface mapping data relates to a patient's teeth for implementing an orthodontic wireframe retainer according to an embodiment of the invention. As depicted in Figure 7 a 3D laser topography system 750 comprises an optical measurement sub-system 740 which operates in conjunction with multi-axis positioning sub-system, enclosure, and microprocessor controller, these not being shown for clarity. Within the optical measurement sub-system 740 a laser 710 acts as an optical source projecting onto the surface 730 being measured wherein the reflected optical signal is coupled to a CCD detector 720. As the surface being measured shifts from a first height 730A to a second height 730B, a distance £>, , the reflected optical signal shifts from first CCD location 760A to second CCD location 760B, a distance D₂ .

Accordingly a scaling factor, k , equates positional changes of the reflected laser spot to vertical changes in the surface being measured as given by Equation (1) below.

D_x = k D₂ (1)

[0059] 3D laser topography system 750 moves the sample through a translational process beneath the optical measurement sub-system 740 allowing the full three-dimensional object to be characterized resulting in a data file allowing surface contour mapping to be performed such as depicted by mouth contour surface 860 in Figure 8. The resulting mouth contour surface 860 can then be employed to provide an appliance - mouth contour 870 from which the appliance 880 can be manufactured.

[0060] Referring to Figure 8 there is depicted an exemplary process flow for implementing an orthodontic appliance exploiting an orthodontic wireframe retainer according to an embodiment of the invention such as described above in respect of Figures 5A, 6A and 6B respectively. Accordingly the process begins with step 805 wherein a molding of the patient is obtained using one or other of the known prior art techniques such as where the impression is carried out by placing a viscous liquid material into the patient's mouth, usually in a customised dental impression tray. The material, usually an alginate, then sets to become an elastic solid, and, when removed from the mouth, provides a detailed and stable reproduction of the patient's teeth. Common materials used for dental impressions are sodium alginate, polyether and silicones - both condensation-cured silicones and addition-cured silicones, such as polyvinyl siloxane. Historically plaster of Paris, zinc oxide eugenol and agar have been used. Next in step 810 the patient mold is scanned and then converted to a framework model in step 815 such as depicted by mouth contour surface 860.

[0061] Next in step 820 the patient teeth undercut is established within the framework model based upon an automated algorithm wherein a teeth undercut profile is then generated in step 825. Subsequently in step 830 an orthodontic appliance is selected, for example a retainer, wherein the generated teeth undercut profile is merged with the selected orthodontic appliance model in step 835. In step 840 the resulting patient specific orthodontic appliance model is modified as appropriate before in step 845 it is transmitted to a CAM system wherein in step 850 the patient specific orthodontic appliance model is manufactured.

[0062] Optionally, the teeth undercut profile may be established in conjunction with or solely in dependence upon a user's input. Alternatively an inter-oral scanning system exploiting techniques such as confocal microscopy, optical coherence tomography, photogrammetry, active and passive stereovision and triangulation, and interferometry may be employed thereby removing the initial step, see for example Logozzo et al in "A Comparative Analysis Of Intraoral 3d Digital Scanners For Restorative Dentistry" (Internet J. Medical Technology, Vol. 5, No. 1, ISSN: 1559-4610). However, such systems are expensive and accordingly multiple orthodontists may leverage a centralized scanning facility by taking impressions and sending these to this facility for scanning. Such a centralized scanning facility or other facilities may then provide the contour generation, wire mesh formation, and fabrication of the designed orthodontic appliance. Optionally, the scanning of the impression may be performed directly without requiring the translation of the negative impression to a positive impression through a molding process employing the impression made directly by the patient.

[0063] Now referring to Figure 9 there is depicted an exemplary process flow for implementing an orthodontic appliance exploiting an orthodontic wireframe retainer according to an embodiment of the invention. At step 905 a digital representation of patient's upper and / or lower mouth is taken according to the orthodontic appliance and / or orthodontic procedure which is then transmitted to an orthodontic system in step 940 allowing an orthodontic practitioner or other authorized user to view the acquired scan such as to verify its acceptance or to proceed to assessing suitability for a PAtient SPecific ORthodontic Appliance (PASPORA). Accordingly the data file for the intra-oral scan is stored locally at the orthodontic system in step 940 and then transmitted to an orthodontic CAD system (OCAD) in step 950 for storage and / or further processing.

[0064] Alternatively, the exemplary process flow begins at step 910 wherein a negative impression of the patient's upper and / or lower mouth is taken which is then molded in step 920 into a positive impression. This is then scanned in step 930 to provide the digital representation of patient's upper and / or lower mouth which is then communicated to either an orthodontic system in step 940 allowing an orthodontic practitioner or other authorized user to view the acquired scan such as to verify its acceptance or is communicated to an OCAD in step 950. In either event the digitized patient data may be assessed for suitability with respect to a PASPORA prior to the process proceeding.

[0065] At step 950 the OCAD allows the extraction of the undercut data of the patient from their digitized dental impression allowing for the determination of the undercut profile at the predetermined regions of the patient's teeth as determined in dependence of multiple factors, including but not limited to, the digitized dental impression, the PASPORA to be fitted, and the orthodontic treatment or procedure to be performed. This process may include transmitting data including, but not limited to, the wireframe model data, digitized patient dental impression, and simulations of PASPORA operation back to the orthodontist executing for example step 910 or step 905 for review and discussion with the patient prior to committing to manufacturing. Alternatively, this data may be provided to a third party in step 970 for review such as for example a provider of dental plan coverage for the patient, a manufacturer of the PASPORA, the patient at their personal email address, and a data storage server.

[0066] Accordingly upon completion of the design, verification and modification of the PASPORA using the generated undercut profile a wireframe model of the PASPORA is communicated in step 960 to a first manufacturing system or to a second manufacturing system in step 990. The first manufacturing system in step 960 may for example be a CAM system providing milling of the PASPORA based upon the wireframe model and / or an alternative representation of the wireframe model compatible with the CAM system. Milling of a material that is biocompatible may include for example milling stainless steel, a machinable plastic, machinable resin, or a machinable ceramic such as alumina or zirconia for example. Such materials include those within the following prior art references for example including, but not limited to, "Biomaterials Tutorial" (Sigma-Aldrich, http.V/www.sigmaaldrich. com/materials-science/biomaterials/tutori l. html) , "Characteristics of Metals used in Implants" (J Endourol. 1997, pp383-9), and "Biocompatible Materials for the Human Body" (Business Communications Co., Report B-072N, 2003). It would be evident that a wider range of materials may exist when compared to those considered biocompatible for in vivo or in-body applications.

[0067] Subsequent to its manufacturing in step 960 the PASPORA may be subject to additional post-processing steps including, but not limited to, sintering, passivation, coating, and laser marking. Alternatively in step 990 the PASPORA is manufactured using a 3D printing CAM system. Similarly subsequent to its manufacturing in step 960 the PASPORA may be subject to additional post-processing steps including, but not limited to, sintering, passivation, coating, and laser marking. Alternatively, the wireframe retainer is designed, printed in 3D using a special composite and then the composite framework is then cast in chrome cobalt allow or another material providing the required mechanical and biocompatible properties. Optionally, the wireframe retainer may be 3D printed in the composite for fit verification etc. and then 3D printed into the final material or cast.

[0068] Optionally, the orthodontic system in step 940 may be the system performing the intraoral scan in step 905 or alternatively it may be associated with a third party such as for example another part of the orthodontic practice, another part of an orthodontic facility, or an independent provider of orthodontic appliances. It would be evident that storage of the scanned patient data, the wireframe model of the PASPORA, and other files associated with the process may be stored locally to one or more of the systems described or may be stored remotely in a remote server. Optionally, the scanning of the impression may be performed directly without requiring the translation of the negative impression to a positive impression through a molding process employing the impression made directly by the patient.

[0069] It would be evident to one skilled in the art that the process flows described in respect of Figures 8 and 9 support a variety of boundaries between orthodontic practitioner, CAD implementation and PASPORA design, and CAM manufacturing of the PASPORA. In some instances all stages may be provided within a single vertically integrated orthodontic facility, such as for example a hospital or third party orthodontic provider such as a large orthodontic practice. In other instances a single integrated CAD - CAM service provider may support multiple orthodontic practices implementing either of the physical and / or intra-oral scanning approaches to data acquisition. In other instances digitization of the physical molding may be provided by an intermediate provider to the CAD - CAM service provider or may be part of their operations. In other instances the digitization of the physical molding may be within the orthodontic practice itself. Accordingly, a variety of supply chain scenarios may be supported as well as a variety of CAM based manufacturing processes and materials. In some embodiments of the invention the CAD - CAM wireframe model generated may comprise two or more elements which are manufactured separately and then combined to provide the PASPORA.

[0070] Referring to Figure 10 there are depicted some orthodontic appliances of the prior art that may exploit an orthodontic wireframe retainer according to an embodiment of the invention. First and second images 1010 and 1020 depicting Maxillary and sprung palatal expanders respectively whilst third and fourth image depict first and second space maintainers. Similarly Figure 1 1 depicts orthodontic appliances of the prior art that may exploit an orthodontic wireframe retainer according to an embodiment of the invention including first and second retainers 1 1 10 and 1 120 respectively supporting replacement teeth as well as spring retainer 1 130 and thumb crib 1 140. Figure 12 also depicts orthodontic appliances of the prior art that may exploit an orthodontic wireframe retainer according to an embodiment of the invention including pendulum 1210, Nance holding arch 1220, and transpalatal arch 1230. It is evident in these prior art orthodontic devices that replacing the wires, bands, and other retainer like elements with an undercut engaging element such as described supra in respect of Figures 5 and 6 would provide to improved patient experience and thereby increase the likelihood of their completing the orthodontic regimen that they are engaged in.

[0071] Within the embodiments of the invention described above in respect of Figures 5 through 9 and their implementation into PASPORA such as depicted in Figures 10 through 12 that the physical wireframe is derived from a drawn virtual wireframe. This virtual wireframe is planned using software which may be specifically designed for this purpose or may be an application or module design to provide compatibility with a commercial orthodontic CAD software suite such as 3shape's OrthoAnalyzer™, Cadent's OrthoCAD, Sirona's Cerec™, and "SureSmile" for example. Essentially, there are two core elements to the software providing such undercut retainers according to embodiments of the invention. The first is an electronic surveyor that allows for the precise determination of the line of contour of the undercut of the patient and the second part is a CAD tool allowing for multiple adjustments / refinements in the shape and thickness of the wireframe to be made with their visualization in respect of the patient and the PASPORA overall. This software as described supra may be provided to the orthodontic practitioner directly or to a third party service provider to the orthodontic practitioner. It would also be possible for a third party service provider to engage directly with patients seeking replacement retainers for example by retrieving their wireframe model and re-manufacturing without variation or receiving an impression directly from the patient which is scanned and either used directly or used to determine variations in the current wireframe model with or without orthodontic practitioner overview.

[0072] The determination of a path of insertion respecting the line of contour of the dentition provides maximum retention whilst allowing reduction and / or minimization of any force exerted onto the patient's dentition. In addition to the material used to manufacture embodiments of the invention being biocompatible and readily used in removable prosthodontics and orthodontics it would be beneficial in some embodiments for the material to also allow for the addition of any springs or auxiliaries by soldering etc. As evident from the discussions supra the methods of design and fabrication of removable orthodontic / prostodontic appliances allow for the creation of multiple designs all based on the same operating principles of embodiments of the invention.

[0073] According to embodiments of the invention the path of insertion respecting the line of contour of the dentition may be determined directly from the 3D scanned image of the patient's dentition or alternatively the path of insertion may be determined by combining the 3D scanned image of the patient's dentition with additional dentition information including, but not limited to, that derived from standard models of dentition based upon patient age, sex, race, etc.; x-ray analysis, ultrasound analysis and visual / physical inspection.

[0074] Referring to Figure 13 there are depicted first to seventh images 1310 through 1370 respectively relating to 3D digitized patient dental data and it's processing by a software system executing software according to an embodiment of the invention to establish the undercut path for insertion of a wireframe retainer according to an embodiment of the invention. As depicted:

^■ first image 1310 depicts 3D digitized patient data in plan or top view;

^■ second image 1320 depicts 3D digitized patient data viewed from the left hand side;

^■ third image 1330 depicts 3D digitized patient data viewed from the right hand side;

^■ fourth image 1340 depicts software extracted undercut path data, dark line along teeth, presented on the 3D digitized patient data viewed from the left hand side;

^■ fifth image 1350 depicts software extracted undercut path data, dark line along teeth, presented on the 3D digitized patient data viewed from the left hand side;

^■ sixth image 1360 depicts software extracted undercut path data, dark line along teeth, presented on the 3D digitized patient data viewed from the right hand side; and

^■ seventh image 1370 depicts software extracted undercut path data, dark line along teeth, presented on the 3D digitized patient data viewed from the right hand side.

[0075] Now referring to Figure 14 there are depicted first to seventh images 1410 through 1470 respectively relating to CAD image data relating to the patient showing the undercut path and clasps together with other clasps and ball clasps according to embodiments of the invention. As depicted:

^■ first image 1410 depicts the 3D digitized patient data in plan or top view with a wireframe retainer according to an embodiment of the invention in place;

^■ second image 1420 depicts the processed 3D digitized patient data with extracted undercut path data and a wireframe retainer according to an embodiment of the invention with clasps from the right hand side;

^■ third image 1430 depicts the processed 3D digitized patient data with extracted undercut path data and a wireframe retainer according to an embodiment of the invention with clasps from the right hand side;

^■ fourth image 1440 depicts the processed 3D digitized patient data with a wireframe retainer according to an embodiment of the invention with close up of clasp on second molar under the line of contour;

■ fifth image 1450 depicts the processed 3D digitized patient data with a wireframe retainer according to an embodiment of the invention with clasp on second molar under the line of contour; ^■ sixth image 1460 depicts the processed 3D digitized patient data with a wireframe retainer according to an embodiment of the invention depicting a ball clasp in the lingual aspect; and

^■ seventh image 1470 depicts the processed 3D digitized patient data with a wireframe retainer according to an embodiment of the invention depicting a ball clasp in the buccal aspect.

[0076] Referring to Figure 15 there are depicted first to fourth 1510 through 1540 respectively relating to CAD image data of a wireframe retainer prior to data conversion for transmittal to a CAM system according to embodiments of the invention. As depicted:

^■ first image 1510 depicts the 3D digitized patient data in plan or top view with a wireframe retainer according to an embodiment of the invention in place;

^■ second image 1530 depicts the resulting 3D digitized wireframe retainer for the patient according to an embodiment of the invention from the right hand side;

^■ third imagel 530 depicts the resulting 3D digitized wireframe retainer for the patient according to an embodiment of the invention from the top view; and

■ fourth image 1540 depicts the resulting 3D digitized wireframe retainer for the patient according to an embodiment of the invention from the left hand side.

[0077] Beneficially embodiments of the invention allow for:

^■ a CAD CAM designed orthodontic removable appliance, wherein a path of insertion in conjunction with an accurate determination of the line of contour allows for the design of a retentive appliance that does not rely on acrylic coverage of soft tissue for retention;

■ a scanned impression allows for the design of a virtual retainer device respecting the line of draw and line of contour using known technology;

■ a design can be altered or modified as appropriate on a computer at the design phase allowing different configurations of frameworks to also be tested and / or investigated;

■ additional active or passive components can be added or incorporated in the design as prescribed by the practitioner;

■ good retention is achieved without resorting to bulky acrylic components or significant orthodontic hardware in the patient's mouth; ^■ orthodontic devices may be implemented in a manner providing enhanced cosmetic appearance for the patient;

^■ prototyping via 3D printing may be employed to verify fit etc. by dentist prior to manufacture of final orthodontic appliance; and

^■ the dentist / orthodontist has the capability to review, correct and approve the computer generated design in contrast to the prior art.

[0078] It would be evident to one skilled in the art that false colour processing may be applied to the images to highlight elements of the patient dental data, the processed dental data such as employed in fourth to seventh images 1340 to 1370 respectively; and wireframe retainer. Such graphics processing being controllable under the direction of a user of the CAD system to aid / enhance the design of the wireframe retainer according to an embodiment of the invention.

[0079] The inventors have found that some patients do not have undercuts on one or more of their teeth either impacting the establishment of an undercut path for insertion of a wireframe retainer according to an embodiment of the invention or impacting the design of the wireframe retainer itself. Accordingly, in some embodiments of the invention, such as described below in respect of Figures 16 and 17, it would be beneficial therefore to create one or more undercut sections upon one or more teeth in order to establish those elements of the undercut path or the design of the wireframe retainer.

[0080] Referring to Figure 16 there are depicted first to third images 1600A to 1600C respectively. First image 1600 A depicts the patient's tooth 1610 without undercut. As evident in second image 1600B the tooth 1610 has had an undercut 1620 formed close to the gum 1640. Then in third image 1600C the undercut 1620 is shown with the retainer 1630 inserted against it close to the patient's gum 1640. The undercut 1620 may be formed for example through a direct physical removal process such as through use of a diamond tipped saw blade for example, or through an indirect removal process, such as high pressure water cutting and laser ablation for example. Optionally, high pressure water cutting may include the addition of an abrasive element with the water. The depth of the undercut may be only a few thousands of an inch, e.g. 1 to 10 thousands of an inch (e.g. 30 microns to 250 microns). The width of the undercut may be similarly only a couple of thousands of an inch, e.g. 1 to 5 thousands of an inch (e.g. 30 microns to 130 microns). With direct physical processes such as diamond tipped saw blade the profile of the undercut 1620 may be defined with good repeatability as the initial contact of the saw blade with tooth may be detected. This would allow, for example, the retainer 1630 to be designed with a predetermined profile along the edge engaging the tooth 1610. With indirect physical processes the exact depth and profile of the undercut formed is subject to other factors influencing the final result such as the depth and strength of the enamel on the patient's tooth for example. Accordingly, a second stage of measuring the undercut may in some instances be performed prior to the design and manufacturing of the wireframe retainer.

[0081] Now referring to Figure 17 there are depicted first to third images 1700 A to 1700C respectively. First image 1700A depicts the patient's tooth 1710 without undercut. As evident in second image 1700B the tooth 1710 has had an element 1720 bonded to the inner surface of the tooth 1710 close to the gum 1740 so that a gap exists between the element 1720 and gum 1740. Then in third image 1700C it can be seen that the wireframe retainer 1730 has been inserted between the element 1720 and patient's gum 1740. Element 1720 may, for example, be formed from a polymer such as polyvinyl chloride, polypropylene, polyacrylonitrile, polyvinyl butyral. Alternatively, element 1720 may be formed from a ceramic such as aluminium oxide, aluminium nitride, and boron nitride or a metal such as surgical stainless steel, 316 stainless steel, chromium, nickel, iron-chromium alloys, cobalt chromium alloys, titanium, titanium niobium alloys, titanium molybdenum alloys, niobium, and niobium alloys. The element 1720 may be bonded to the tooth 1710 by an adhesive or cement for example, including but not limited to, water based acid-base cements, such as zinc phosphate, zinc polyacrylate(polycarboxylate), glass ionomer, etc. including those containing metal oxide or silicate fillers embedded in a salt matrix for example; non-aqueous acid-base cements such as eugenol and non-eugenol zinc oxide for example; resin-based cements such as acrylate and methacrylate for example; as well as others such as employing an ion leaching agent, a polycarboxylic acid, sugar, and water; 4-methacryloxyethyl trimellitic acid and water with a powder material comprising a powdered fluoroalumino silicate glass or a powdered metal oxide for example.

[0082] Within Figure 17 the element 1720 is depicted as being positioned on the patient's tooth 1710 with a spacing between the lower surface of element 1720 and upper surface of patient's gum 1740. However, according to an alternate embodiment of the invention the lower surface of the element 1720 may be in contact with the upper surface of patient's gum 1740 prior to the insertion of wireframe retainer 1730. Accordingly, the wireframe retainer 1730 is then inserted between the patient's gum 1740 and the lower surface of element 1720. As depicted element 1720 is designed such that the wireframe retainer 1730 fits below the element 172. However, element 1720 may be designed such that wireframe retainer 1730 engages directly upon it rather than between it and the patient's gum for example.

[0083] The depth of the element 1720 attached may be only a few thousands of an inch, e.g. 1 to 10 thousands of an inch (e.g. 30 microns to 250 microns) although it may be deeper. The height of the undercut may be similarly only a couple of thousands of an inch, e.g. 1 to 5 thousands of an inch (e.g. 30 microns to 130 microns) although it may be thicker. With a direct physical attachment the profile of the resulting undercut formed between the element 1720 and gum 1740 may be defined with good repeatability allowing, for example, a predetermined profile for the engaging edge of the retainer 1730 to be employed. In some other instances depth and profile of the undercut formed may be subject to other factors influencing the final result such as the repeatability of the attachment process, adhesive spill- out, etc. Accordingly, a second stage of measuring the undercut formed may in some instances be performed prior to the design and manufacturing of the wireframe retainer after the attachment.

[0084] Specific details are given in the above description to provide a thorough understanding of the embodiments. However, it is understood that the embodiments may be practiced without these specific details. For example, circuits may be shown in block diagrams in order not to obscure the embodiments in unnecessary detail. In other instances, well-known circuits, processes, algorithms, structures, and techniques may be shown without unnecessary detail in order to avoid obscuring the embodiments. Implementation of the techniques, blocks, steps and means described above may be done in various ways.

[0085] Also, it is noted that the embodiments may be described as a process which is depicted as a flowchart, a flow diagram, a data flow diagram, a structure diagram, or a block diagram. Although a flowchart may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be rearranged. A process is terminated when its operations are completed, but could have additional steps not included in the figure.

[0086] Furthermore, embodiments may be implemented by hardware, software, scripting languages, firmware, middleware, microcode, hardware description languages and/or any combination thereof. When implemented in software, firmware, middleware, scripting language and/or microcode, the program code or code segments to perform the necessary tasks may be stored in a machine readable medium, such as a storage medium. A code segment or machine-executable instruction may represent a procedure, a function, a subprogram, a program, a routine, a subroutine, a module, a software package, a script, a class, or any combination of instructions, data structures and/or program statements. A code segment may be coupled to another code segment or a hardware circuit by passing and/or receiving information, data, arguments, parameters and/or memory contents. Information, arguments, parameters, data, etc. may be passed, forwarded, or transmitted via any suitable means including memory sharing, message passing, token passing, network transmission, etc.

[0087] For a firmware and/or software implementation, the methodologies may be implemented with modules (e.g., procedures, functions, and so on) that perform the functions described herein. Any machine-readable medium tangibly embodying instructions may be used in implementing the methodologies described herein. For example, software codes may be stored in a memory. Memory may be implemented within the processor or external to the processor and may vary in implementation where the memory is employed in storing software codes for subsequent execution to that when the memory is employed in executing the software codes. As used herein the term "memory" refers to any type of long term, short term, volatile, nonvolatile, or other storage medium and is not to be limited to any particular type of memory or number of memories, or type of media upon which memory is stored.

[0088] Moreover, as disclosed herein, the term "storage medium" may represent one or more devices for storing data, including read only memory (ROM), random access memory (RAM), magnetic RAM, core memory, magnetic disk storage mediums, optical storage mediums, flash memory devices and/or other machine readable mediums for storing information. The term "machine-readable medium" includes, but is not limited to portable or fixed storage devices, optical storage devices, wireless channels and/or various other mediums capable of storing, containing or carrying instruction(s) and/or data.

[0089] The methodologies described herein are, in one or more embodiments, performable by a machine which includes one or more processors that accept code segments containing instructions. For any of the methods described herein, when the instructions are executed by the machine, the machine performs the method. Any machine capable of executing a set of instructions (sequential or otherwise) that specify actions to be taken by that machine are included. Thus, a typical machine may be exemplified by a typical processing system that includes one or more processors. Each processor may include one or more of a CPU, a graphics-processing unit, and a programmable DSP unit. The processing system further may include a memory subsystem including main RAM and/or a static RAM, and/or ROM. A bus subsystem may be included for communicating between the components. If the processing system requires a display, such a display may be included, e.g., a liquid crystal display (LCD). If manual data entry is required, the processing system also includes an input device such as one or more of an alphanumeric input unit such as a keyboard, a pointing control device such as a mouse, and so forth.

[0090] The memory includes machine-readable code segments (e.g. software or software code) including instructions for performing, when executed by the processing system, one of more of the methods described herein. The software may reside entirely in the memory, or may also reside, completely or at least partially, within the RAM and/or within the processor during execution thereof by the computer system. Thus, the memory and the processor also constitute a system comprising machine-readable code.

[0091] In alternative embodiments, the machine operates as a standalone device or may be connected, e.g., networked to other machines, in a networked deployment, the machine may operate in the capacity of a server or a client machine in server-client network environment, or as a peer machine in a peer-to-peer or distributed network environment. The machine may be, for example, a computer, a server, a cluster of servers, a cluster of computers, a web appliance, a distributed computing environment, a cloud computing environment, or any machine capable of executing a set of instructions (sequential or otherwise) that specify actions to be taken by that machine. The term "machine" may also be taken to include any collection of machines that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein.

[0092] The foregoing disclosure of the exemplary embodiments of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many variations and modifications of the embodiments described herein will be apparent to one of ordinary skill in the art in light of the above disclosure. The scope of the invention is to be defined only by the claims appended hereto, and by their equivalents.

[0093] Further, in describing representative embodiments of the present invention, the specification may have presented the method and/or process of the present invention as a particular sequence of steps. However, to the extent that the method or process does not rely on the particular order of steps set forth herein, the method or process should not be limited to the particular sequence of steps described. As one of ordinary skill in the art would appreciate, other sequences of steps may be possible. Therefore, the particular order of the steps set forth in the specification should not be construed as limitations on the claims. In addition, the claims directed to the method and/or process of the present invention should not be limited to the performance of their steps in the order written, and one skilled in the art can readily appreciate that the sequences may be varied and still remain within the spirit and scope of the present invention.

Claims

CLAIMS What is claimed is:

1. A method of:

retaining an orthodontic appliance within the mouth of a patient solely by engagement of a predetermined element of the orthodontic appliance with an undercut portion of a predetermined subset of the teeth of the patient.

2. The method according to claim 1 wherein;

the undercut is between the line of contour of the tooth and the gingival margin.

3. The method according to claim 1 wherein;

the predetermined element of the orthodontic appliance engaging with the undercut portion of the predetermined subset of the teeth of the patient is on located under the line of contour and on the inner portion of their dentition.

4. The method according to claim 1 wherein;

the predetermined element of the orthodontic appliance engaging with the undercut portion of the predetermined subset of the teeth of the patient penetrates only to a predetermined point in the region between two adjacent teeth.

5. The method according to claim 1 wherein;

the undercut portion of a predetermined subset of the teeth of the patient is determined in dependence upon at least one of a direct scan of the patient's teeth and a scan of an impression of the patient's teeth.

6. The method according to claim 1 wherein,

a predetermined portion of the undercut on the predetermined subset of the teeth of the patient is formed by the removal of material from the patient's teeth.

7. The method according to claim 1 wherein,

a predetermined portion of the undercut on the predetermined subset of the teeth of the patient is formed by the addition of a predetermined material to the patient's teeth.

8. An orthodontic device comprising:

a frame retaining the orthodontic appliance within the mouth of a patient solely by engagement of a predetermined element of the orthodontic appliance with an undercut portion of a predetermined subset of the teeth of the patient.

9. The method according to claim 8 wherein;

10. The method according to claim 8 wherein;

1 1. The method according to claim 8 wherein;

12. The method according to claim 8 wherein;

13. The method according to claim 8 wherein,

14. The method according to claim 8 wherein,