The present Application relates to the fields of orthodontics, implant dentistry, cosmetic dentistry, and dentofacial orthopedics, and more specifically, but not exclusively, to an orthodontic aligner with an elastomeric inner functional layer and a rigid outer functional layer, and to methods of orthodontic treatment using the orthodontic aligner.
Orthodontic and dental treatments generally have two objectives: functional and cosmetic. Functionally, an orthodontic treatment corrects the orientation of teeth and the shape of a bite. Cosmetically, orthodontic treatments smooth out variations in appearances of the teeth and straighten a patient's smile.
These goals are not always achievable at the same time. Certain orthodontic treatments are highly effective but, at least temporarily, are aesthetically distasteful. Still other dental treatments achieve cosmetic improvements but do not assist at all with respect to functional improvements. An example in the first category is metal braces, while an example in the second category is veneers.
Clear aligners are a relatively recent addition to orthodontic treatments that achieve functional benefits while also being a cosmetic improvement compared to metal braces. Clear aligners are molded of thermoplastic polyurethane and are typically designed to fit over attachments, also known as buttons, which are bonded to the labial and buccal surfaces of the teeth. The force of the aligner acting on the attachments causes the teeth to move. Clear aligners are available today under the trademarks Invisalign® by Align Technologies and Clarity® by 3M, among others.
Despite their recent popularity, clear aligners suffer from significant limitations that hamper their utility and effectiveness.
First, clear aligners are unable to be worn during eating, because the elastomeric material cannot withstand the forces of chewing and the temperature ranges of foods. In addition, food may cause the aligners to stain. As a result, it is necessary to remove and store the aligner during eating.
Second, most clear aligners are currently implemented with attachments on the labial and buccal surfaces of the teeth. Attaching on the labial and buccal surface is necessary because, due to the angulation of the teeth and the limitations of the strength of the elastomer, the clear aligner is unable to apply sufficient force on attachments connected to the lingual surface of the teeth. Also, attachments are necessary for vertical extrusion of teeth. Labial attachments are aesthetically displeasing, and, especially in combination with the frequent removal of the aligner as discussed above, may cause embarrassment to the patient.
Third, clear aligners are currently unable to effectively address certain cosmetic challenges. For example, when a patient is missing a tooth, the solution that is available with clear aligners is to include a pontic. A pontic is a tooth-shaped place holder, created in the space left by a missing tooth in the aligner. However, when the aligner is removed (e.g., for eating), the pontic must be removed with it. Similarly, aligners are unable to effectively compensate for developing depths, thicknesses, or spaces in the dentition. At best, at specific points, the aligner may be constructed with a tooth cavity in the tray being marginally wider, to allow space for a temporary bonding veneer to be applied to a particular tooth. This solution, however, is still subject to the orthodontist's incremental adjustment of the teeth, and comes at the expense of undesirable aesthetics between visits.
Still another cosmetic drawback of clear aligners is their ability to become stained. For example, if a patient smokes, or eats turmeric, the aligners will stain and pick up fragments that highlight the architecture of the various appliances and attachments. Also, if the teeth are stained, the stain will show through the aligners.
Clear aligners are also unable to achieve certain functional objectives, even in combination with other treatments. First, in general, if the force exerted by the clear aligner is not strong enough to move the tooth, the plastic material of the aligner becomes misshapen and deforms outward, leading to patient discomfort and lack of effective movements. Furthermore, forces of clear aligners are limited to horizontal and angular movements, without labial and buccal attachments for lateral force. In addition, clear aligners are not able to achieve certain specific treatments. For example, should a patient have a bimaxillary protrusion, the ideal form of treatment, although least common, is to perform sequential distalization of the molars. The sequential distalization moves the molars distally which makes space for the protruding teeth to be brought back in alignment with the others. However, the material of elastomeric aligners is too soft to properly track the teeth with enough force to distalize the molars and bicuspids in sequence. As a result, if clear aligners are used, the most prevalent treatment of bimaxillary protrusion is to remove healthy teeth that are closest to the deformity. Removing healthy teeth is obviously a suboptimal outcome.
As another example, a patient may have occlusions between teeth as well as a class 3 malocclusion or an asymmetry of the mandible and maxilla arches. The appropriate treatment for severe asymmetry is orthognathic surgery; however, it is also necessary to perform an orthodontic treatment prior to surgery, so that the teeth will be decompensated so that they will meet properly following the surgery. Removable aligners are unable to be used for filling in such occlusion-related gaps after decompensation, prior to surgery.
As still another example, should a patient have TMJ (temporomandibular joint) pain due to mild mandible/maxilla asymmetry, malocclusions, or various forms of arthritis, the patient may be given a special removable appliance that accommodates the angulation of the jaw, or fills in the occlusal gaps. However, this removable appliance cannot simultaneously move teeth into ideal position, and also the patient cannot eat while wearing the removable appliance. Accordingly, the patient may have bite blocks implemented with a composite material to resurface the tooth's height and shape, thereby improving the occlusion at the ideal mandibular/maxillary position. However, adjusting bite blocks while wearing clear aligners is nearly impossible, because the aligners are fitted to the pre-measured shape of the teeth.
Aligners made of ceramic and other rigid materials have been proposed. However, if the ceramic is solid, there will necessarily be an unfilled cavity around the plurality of the teeth. This unfilled cavity may allow entry of food particles. Flexible ceramics do exist but either have a cloth-like structure, which is too soft for orthodontic treatment, or they are flexible in their green state, which may leach chemicals.
It is an object of the present disclosure to provide an alternative to a clear aligner that is capable of overcoming the above-described challenges. Specifically, it is an object of the present disclosure to provide an aligner that is capable of being worn while eating. It is a further option of the present disclosure to provide an aligner that does not require the use of labial attachments for movements that would require the use of labial attachments in other types of aligner devices. It is a further object of the present disclosure to provide an aligner that is able to effectively address aesthetic challenges such as missing teeth, or uneven teeth, or impacted teeth, even as the treatment is being performed with the aligner. It is a further object of the present disclosure to provide an aligner that is capable of being used in conjunction with various orthodontic, dental, orthognathic, and other treatments which are currently unavailable with clear aligners.
The present disclosure introduces a new paradigm for the construction of aligners. The aligners are made of a structure having multiple functional layers, with the inner functional layer being elastomeric and the outer functional layer being rigid. The rigid outer functional layer is sufficiently strong and heat-resistant to withstand the forces and temperatures of eating. The rigid outer functional layer also provides sufficient lateral force to work on teeth even using lingual or palatal attachments, and to perform orthodontic treatments that are unavailable with elastomeric aligners. The rigid outer functional layer may either end at the gingival line or may extend over the labial side of the maxilla or over the palate and other medical devices configured at the palate, depending on the desired treatment goals.
The present disclosure further discloses various forms of orthodontic treatment that may be achieved with the orthodontic aligners described herein.
According to a first aspect, an orthodontic aligner includes an inner functional layer comprised of an elastomer, and a non-elastomeric outer functional layer.
In another implementation according to the first aspect, the outer layer is comprised of a biocompatible rigid or semi-rigid polymer.
In another implementation according to the first aspect, the inner functional layer and outer functional layer are made of a functionally graded material. Optionally, the functionally graded material is a functionally graded polymer having greater elasticity at the inner functional layer and greater rigidity at the outer functional layer.
In another implementation according to the first aspect, the aligner further includes a plurality of inner cavities within the inner layer, each inner cavity shaped to receive therein a tooth attachment. Optionally, the inner cavities are configured to receive therein lingual tooth attachments.
In another implementation according to the first aspect, the elastomeric inner functional layer is molded to fit a tooth with sufficient tightness to function as a gasket preventing entry of food particles between the tooth and the orthodontic aligner.
In another implementation according to the first aspect, a combined thickness of the outer and inner functional layers is up to 800 μm in a region surrounding at least one tooth.
In another implementation according to the first aspect, a thickness of the outer layer in said region is approximately 100 microns at a region corresponding to a root of a tooth, and up to approximately 500 microns at a region corresponding to a tip of the tooth, and a thickness of the inner layer is between approximately 300 to 400 microns at the root, and between approximately 50 to 100 microns at the tip. Generally, the thickness of the layers in different regions depends on the material that is used, as well as aesthetic considerations. Thus, when desired for aesthetic purposes, the thickness of the outer layer may be even greater than 500 microns at the tip.
In another implementation according to the first aspect, the aligner maintains structural integrity at temperatures of between approximately −3° C. to 105° C.
In another implementation according to the first aspect, the aligner maintains structural integrity at pressures of up to approximately 800 psi. In particular, the rigid outer functional layer maintains structural integrity at typical pressures of chewing, e.g., up to at least about 160 psi. Preferably, the rigid outer functional layer maintains structural integrity at even greater pressures, such as 700-800 psi, which are pressures that are typical for dentures and crowns.
In another implementation according to the first aspect, the aligner includes at least one region of increased thickness on an external face of the outer functional layer, said region of increased thickness corresponding to a region of decreased thickness of a corresponding tooth or arch point. Optionally, the region of increased thickness has a thickness of up to approximately 8,000 μm, or even greater, if desired for aesthetic purposes.
In another implementation according to the first aspect, the aligner includes at least one pontic, and the pontic is comprised of a material of the outer functional layer over an entire dimension of the pontic and includes the material of the inner functional layer at a gingival margin.
In another implementation according to the first aspect, the aligner further includes an extended portion configured to extend over a hard palate of a patient, said extended portion comprised of the material of the outer functional layer, the material of the inner functional layer, a semi-flexible acrylic, or a hard acrylic.
In another implementation according to the first aspect, the outer layer is comprised of regions having various thicknesses so as to form a veneer and thereby smooth out an appearance of adjacent teeth. Optionally, the regions of various thicknesses include at least one of additional thickness at the tip of a tooth and additional thickness in an interproximal space between two teeth.
In another implementation according to the first aspect, a system for orthodontic treatment includes the orthodontic aligner and one or more aligner attachments configured for attachment onto a patient's teeth.
Optionally, the system further includes metal rings or snap buttons for affixation onto molars. Optionally, the system further includes a plurality of magnets, including a first set of magnets for affixation onto teeth and a second set of magnets for affixation onto the aligner. Optionally, the system further includes a temporary grill applied over the outer functional layer. Optionally, the system further includes at least one chain for raising and exposing an impacted tooth.
According to a second aspect, a method of orthodontic treatment is disclosed. The method includes: applying aligner attachments to a plurality of teeth; and affixing an orthodontic aligner to the teeth, said orthodontic aligner including an inner functional layer comprised of an elastomer; a non-elastomeric outer functional layer, and a plurality of inner cavities within the inner layer, each inner cavity shaped to receive therein an aligner attachment, and the affixing step comprises overlaying the inner cavities over the aligner attachments.
In another implementation according to the second aspect, the orthodontic aligner includes a plurality of inner cavities within the inner layer, each inner cavity shaped to receive therein an aligner attachment, and the method further comprises applying aligner attachments to a plurality of teeth; and the affixing step comprises overlaying the inner cavities over the aligner attachments. Optionally, the step of applying aligner attachments comprises applying the attachments to a lingual side of the teeth.
In another implementation according to the second aspect, the orthodontic aligner comprises at least one interproximal section, said interproximal section being configured to apply an interproximal force, and the method further comprises performing distalization with the at least one interproximal section.
In another implementation according to the second aspect, the method further includes performing sequential molar distalization with a series of orthodontic aligners each having different sections of increased thickness.
Optionally, the at least one interproximal section of a first aligner of the series is comprised of the elastomeric functional layer functioning as a spacer, and the at least one interproximal section of a subsequent aligner of the series is comprised of material of the both the elastomeric functional layer and the outer functional layer.
In another implementation according to the second aspect, the orthodontic aligner further comprises a chain, and the method further comprises affixing the chain to an impacted tooth and raising the impacted tooth to a space opened through the performance of the distalization.
In another implementation according to the second aspect, the step of affixing the orthodontic aligner to the teeth comprises first affixing the inner functional layer and subsequently overlaying the outer functional layer onto the inner functional layer.
In another implementation according to the second aspect, the step of affixing the orthodontic aligner to the teeth comprises affixing the aligner to the teeth when the outer functional layer is already adhered to the inner functional layer.
The present Application relates to the fields of orthodontics, implant dentistry, cosmetic dentistry, and dentofacial orthopedics, and more specifically, but not exclusively, to an orthodontic aligner with an elastomeric inner functional layer and a rigid outer functional layer, and to methods of orthodontic treatment using the orthodontic aligner.
Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not necessarily limited in its application to the details of construction and the arrangement of the components and/or methods set forth in the following description and/or illustrated in the drawings and/or the Examples. The invention is capable of other embodiments or of being practiced or carried out in various ways.
As used in the present disclosure, the term “layer” refers to a contiguous section of a particular material. The term “functional layer” refers to a contiguous section of a particular material that has similar properties, e.g., with respect to modulus of elasticity, density, hardness, etc. A layer may have more than one functional layer. For example, the layer may be a functionally graded material. The term “functionally graded material” refers to a composite material whose physical properties vary in composition and structure over different depths. A functionally graded multi-material is a functionally graded material made of different materials.
Referring to
The rigid outer functional layer 11 may be a layer made of any suitably rigid and biologically safe material. Exemplary biocompatible materials are a rigid ceramic, porcelain, zirconia, carbon fiber, polymethyl acrylate, polymethyl methacrylate, a rigid polymer, a semi-rigid polymer, a multilayer rigid film, resins, and other polymers currently used in 3D-printed dentures. These materials are desirable due to their heat resistance, force tolerance, strength, and luminosity. The outer layer may also be a flexible ceramic (which may still be more rigid than the elastomer), provided that the flexible ceramic is medically and food grade safe.
Outer functional layer 11 may be made of any desired color. In particular, the color of outer functional layer 11 may be selected from a spectrum of hues in order to approximate the natural look of a tooth, or a naturally stained tooth, per cosmetic indication of the patient.
The elastomeric inner functional layer 13 may be made of any elastomer that is currently used, or that may become used, in the production of clear aligners. Examples of such elastomers include: a polyurethane resin plastic, which is currently used in clear aligners, a silicone rubber, or another form of thermoplastic elastomer.
Both the rigid outer functional layer 11 and the elastomeric inner functional layer 13 are compatible with being worn while eaten. In particular, the rigid outer functional layer maintains structural integrity at typical pressures of chewing, e.g., up to at least about 160 psi. Preferably, the rigid outer functional layer maintains structural integrity at even greater pressures, such as 700-800 psi, which are pressures that are typical for dentures and crowns. The rigid outer functional layer thus compensates for the structural deficiencies of the elastomeric inner functional layer. Both the outer functional layer 11 and inner functional layer 13 maintain structural integrity at temperatures in which food and drink are commonly ingested, or even higher or lower, e.g., from approximately −3° C. to 105° C. The heat tolerance above 100° C. also enables the use of boiling water for cleaning the aligners, as well as prevents damage to the aligners in the event that a user attempts to ingest food or drink that is too hot.
The aligner 10 has a labial side 12, a buccal side 9, a lingual or palatal side 14, an occlusal side 16, and a gingival side 18 at the point of contact with the gum line. Henceforth in this disclosure, the term “labial” will be used to refer to all fixtures on the side of teeth facing the lips, the term “lingual” will be used to all fixtures on the side of teeth facing the tongue, and the term “occlusal” will be used to refer to all surfaces of the teeth facing opposing teeth. On the lingual side 14, the aligner 10 includes a plurality of cavities that accommodate the contours of aligner attachments 15. Aligner attachments 15 are also referred to herein as buttons. The attachments 15 are used to rotate and extrude the tooth, as well as to help anchor the aligner 10 to the tooth. The attachments 15 may be either pre-manufactured and directly applied via a template tray, or directly fabricated via composite and light cure.
As discussed above, aligner 10 may be used for implementation of various orthodontic treatments, including orthodontic treatments that are not feasible with currently available clear aligners.
The solution is to distalize the molars using a series of aligners 110a, 110b, 110c, as shown in
In another possible implementation, the aligner 10 may be used for sequential distalization of the upper or lower molars and bicuspids. Similar to the stages shown in
An exemplary implementation of sequential distalization is shown in
The elastic functional layer 231 widens interproximal gap 221 by moving tooth 201 leftward. This is shown in the middle section of
At the next stage of the treatment, as interproximal gap 221 increases, aligner 210b includes clastic functional layer 232 as well as rigid functional layer 233. Eventually, the gap is sufficient to fit nearly an entire tooth, and aligner 210c is introduced with thickened rigid layer 234 to complete the widening at gap 221. This state is also shown at
In the view of
Following completion of the movement of the teeth with the aligners, a final tray may be prepared and worn as needed or at night to maintain positioning of the teeth.
The aligners described above may be combined with various other orthodontic treatments. For example, although, for standard treatments, the aligners end at the gingival margin, the aligners (particularly, the rigid layers of the aligners) may alternatively extend to and over the hard palate. The palate extension may serve for pediatric patients as an alternative to a palate expander for dentofacial orthopedics. In addition, the palate extension may serve as a further support to which a traditional denture may be affixed. The palate extension may be made of a different material than the rigid outer layer and elastomeric inner layer. For example, the palate extension may be made of a semi-flexible or hard acrylic. The palate extension may also be made of the same material as the rigid outer layer or the elastomeric inner layer. The composition of the palate extension may be selected on a case-by-case basis, depending on how much flexibility and force is needed in the palate region. Correspondingly, the aligners may also extend over the anterior face of the maxilla. This additional coverage on the maxilla is beneficial when the aligners are used as partial dentures. In situations when multiple teeth are missing, the aligner may need support in order to stay in place. The additional coverage on the maxilla and/or palate provides this support.
As another example of an add-on component, metal rings or snap buttons for the molars may also be fabricated with the aligner. The rings or snap buttons are used for palate expansion or anchorage or other dental procedures. The metal rings may be affixed with temporary cement as used in a fixed palate expander, and may be changed as needed with the entirety of the aligner. The aligner may also be installed with one or more sets of magnets, in order to enable a magnetic attraction to, or a magnetic repulsion from, additional sets of magnets located in the mouth, for example attached to the teeth. A silicone like glue and/or bonding material composites may also be used to further seal the space between the elastomeric layer and enamel of the teeth, to reduce the risk of caries. This glue or bonding material is preferably semi-flexible, to allow for easy removal of the aligner by the orthodontist.
Optionally, purely aesthetic additions may also be implemented. For example, a temporary grill may be applied, in which studding and specialized hues may be applied. The labial grill attachments may be glued, magnetized, or fixed in various ways. The attachments may then be reapplied to future trays. Other less common aesthetic changes, such as creating a fake gap, or fake “buck” teeth, may also be implemented via various thicknesses and hues of the appliance. Such aesthetic changes may be desirable, for example, during orthodontic treatment of actors.
Referring to
A process for manufacture of the multilayer aligners begins with the orthodontist taking an impression or 3d scan of the patient's teeth, in a manner known to those of skill in the art. The impression or scan is converted into a 3d model of the patient's bite in relevant software.
The orthodontist determines a plan for how he or she wishes for the teeth to move. Software may generate a video model showing how an aligner is expected to affect the positioning of the teeth over time. The practitioner confirms that the expected teeth movement is consistent with clinical goals. In addition, the practitioner may use the software to prepare a digital model of the cosmetic improvements he or she desires for the teeth. The cosmetic improvements may include factors such as hues, thickened layers, veneers, coatings, or pontics. Alternatively, software may be equipped with Al technology for recommending to the practitioner the ideal outer and inner proportions of the rigid layer for motion, gripping, and aesthetics. As discussed above, as a result of the addition of the aligners, various teeth are built-up in a veneer-like fashion, or even completely “repositioned” via the illusion of the aligner. Internally, underneath the aligner, the teeth move to approach the appearance of the outer rigid layer.
Following completion of the design, the aligner is manufactured. In a preferred embodiment, the aligner is manufactured in an additive manufacturing process. When the aligner is made of different materials, the additive manufacturing process may be performed using a multi-material 3D printing device. An exemplary multi-material additive manufacturing 3D printing device available today is the Polyjet™ sold by Stratasys, Inc. Other manufacturing techniques are possible, such as hand-forming, gluing, milling, and injection molding.
In one manufacturing approach, the elastomeric inner functional layer and the rigid outer functional layer are manufactured together in the same 3D printing device. Depending on the materials, the 3D printing may be performed through use of a CAD program, for printing on a surface. The layers may optionally be printed over a mold, such as a wax mold, where relevant for the materials. The elastomeric inner layer is then fabricated, and the rigid outer layer is fabricated. These layers may be formed substantially simultaneously or sequentially. The rigid outer layer may be attached to the elastomeric inner layer through any appropriate means, such as gluing, sintering, or curing, depending on the composition of each layer. The minimum thickness of each layer is dictated by the capabilities of the 3d printing device, which currently is approximately 15 μm. The maximum thickness may be up to approximately 8,000 μm or even thicker, as dictated by the cosmetic needs, as discussed above. When deemed necessary, the layers may also be hand-milled and/or hand-affixed.
In an alternative embodiment, the elastomeric inner functional layer and outer functional layer are manufactured separately. The inner functional layer is secured directly to the patient's teeth and gums. This securing may be accomplished through any suitable process, including reliance on the inherent elasticity of the elastomeric layer (e.g., through an interference fit}, or using an adhesive, bands, or magnets. Once the inner functional layer is in place, the outer functional layer is then overlaid onto the inner functional layer, like a shoe over a sock. Separating the manufacturing process is of particular value when the inner functional layer and outer functional layer are made of two different materials that are not easily manufactured together in the same process, such as an elastomer and a ceramic, which require different curing processes.
Should the patient require additional features that require metal sintering that cannot be directly fabricated, the individual additional parts may be fabricated individually. The individual parts may then be attached to the aligner at the point of manufacture, or may be glued to the aligner by the orthodontist, as desired. For example, a grill may be attached to the aligner in a similar manner.
When a final tray (e.g., a retainer} is used, the final tray may be pre-fabricated based on the final estimate of the veneer and crown adjustments of the teeth, taken at the outset of treatment. The final tray may thus serve as a preview for the permanent and semi-permanent final appearance of the teeth. Alternatively the patient can get a final scan upon completion of the treatment, and the final tray may be manufactured following that scan. In the latter case, care should be taken to have the final tray ready as close as possible to cessation of treatment with the aligners, so as to prevent movement of the teeth.
This application is a Continuation-in-Part of PCT Application No. PCT/IL2023/050394, filed Apr. 13, 2023, entitled “Orthodontic Aligner with Elastomeric Inner Surface and Rigid Outer Surface, and Methods of Orthodontic Treatment With Same,” which claims the benefit of priority of U.S. Provisional Application No. 63/330,356, filed Apr. 13, 2022, entitled “Multilayer Orthodontic Aligner with Elastomeric Inner Layer and Rigid Outer Layer and Methods of Orthodontic Treatment with Same,” the contents of each of which are incorporated by reference as if fully set forth herein.
Number | Date | Country | |
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63330356 | Apr 2022 | US |
Number | Date | Country | |
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Parent | PCT/IL2023/050394 | Apr 2023 | WO |
Child | 18912763 | US |