Patent Description:
A common objective in orthodontics is to move a patient's teeth to positions where the teeth function optimally and aesthetically. To move the teeth, the orthodontist begins by obtaining multiple scans and/or impressions of the patient's teeth to determine a series of corrective paths between the initial positions of the teeth and the desired ending positions. The orthodontist then fits the patient to one of two main appliance types: braces or aligners.

Traditional braces consist of brackets and an archwire placed across a front side of the teeth, with elastic ties or ligature wires to secure the archwire to the brackets. In some cases self-ligating brackets may be used in lieu of ties or wires. The shape and stiffness of the archwire as well as the archwire-bracket interaction governs the forces applied to the teeth and thus the direction and degree of tooth movement. To exert a desired force on the teeth, the orthodontist often manually bends the archwire. The orthodontist monitors the patient's progress through regular appointments, during which the orthodontist visually assesses the progress of the treatment and makes manual adjustments to the archwire (such as new bends) and/or replaces or repositions brackets. The adjustment process is both time consuming and tedious for the patient and more often than not results in patient discomfort for several days following the appointment. Moreover, braces are not aesthetically pleasing and make brushing, flossing, and other dental hygiene procedures difficult.

Aligners comprise clear, removable, polymeric shells having cavities shaped to receive and reposition teeth to produce a final tooth arrangement. Dubbed "invisible braces," aligners offer patients significantly improved aesthetics over braces. Aligners do not require the orthodontists to bend wires or reposition brackets and are generally more comfortable than braces. However, unlike braces, aligners cannot effectively treat all malocclusions. Certain tooth repositioning steps, such as extrusion, translation, and certain rotations, can be difficult or impossible to achieve with aligners. Moreover, because the aligners are removable, success of treatment is highly dependent on patient compliance, which can be unpredictable and inconsistent.

Lingual braces are an alternative to aligners and traditional (buccal) braces and have been gaining popularity in recent years. Two examples of existing lingual braces are the Incognito™ Appliance System (<NUM> United States) and INBRACE® (Swift Health Systems, Irvine, California, USA), each of which consists of brackets and an archwire placed on the lingual, or tongue side, of the teeth In contrast to traditional braces, lingual braces are virtually invisible, and, unlike aligners, lingual braces are fixed to the patient's teeth and force compliance. These existing lingual technologies, however, also come with several disadvantages. Most notably, conventional lingual appliances still rely on a bracket-archwire system to move the teeth, thus requiring multiple office visits and painful adjustments. For example, lingual technologies have a relatively short inter-bracket distance, which generally makes compliance of the archwire stiffer. As a result, the overall lingual appliance is more sensitive to archwire adjustments and causes more pain for the patient. Moreover, the lingual surfaces of the appliance can irritate the tongue and impact speech, and make the appliance difficult to clear.

Relevant prior art is exemplified by <CIT> which discloses a method for obtaining a digital model of a heat treatment fixture which is configured to be releasably secured to an orthodontic appliance configured to move patient's teeth.

Therefore, a need exists for improved orthodontic appliances.

The subject technology is illustrated, for example, according to various aspects described below, including with reference to <FIG>. Various examples of aspects of the subject technology are described as numbered clauses (<NUM>, <NUM>, <NUM>, etc.) for convenience. These are provided as examples and do not limit the subject technology.

The invention pertains to a method for obtaining a digital model of a heat treatment fixture for fabricating an orthodontic appliance as defined in claim <NUM>. Further embodiments are set out in the appended dependent claims.

Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Instead, emphasis is placed on illustrating clearly the principles of the present disclosure.

The present technology relates generally to orthodontic appliances and associated systems configured to reposition one or more of a patient's teeth. In particular embodiments, the present technology relates to devices, systems, and methods for attaching or securing orthodontic appliances to the teeth, and associated methods for designing and fabricating such appliances. Specific details of several embodiments of the technology are described below with reference to <FIG>.

Terms used herein to provide anatomical direction or orientation are intended to encompass different orientations of the appliance as installed in the patient's mouth, regardless of whether the structure being described is shown installed in a mouth in the drawings. For example, "mesial" means in a direction toward the midline of the patient's face along the patient's curved dental arch; "distal" means in a direction away from the midline of the patient's face along the patient's curved dental arch; "occlusal" means in a direction toward the chewing surfaces of the patient's teeth; "gingival" means in a direction toward the patient's gums or gingiva; "facial" means in a direction toward the patient's lips or cheeks (used interchangeably herein with "buccal" and "labial"); and "lingual" means in a direction toward the patient's tongue.

As used herein, the terms "proximal" and "distal" refer to a position that is closer and farther, respectively, from a given reference point. In many cases, the reference point is a certain connector, such as an anchor, and "proximal" and "distal" refer to a position that is closer and farther, respectively, from the reference connector along a line passing through the centroid of the cross-section of the portion of the appliance branching from the reference connector.

As used herein, the terms "generally," "substantially," "about," and similar terms are used as terms of approximation and not as terms of degree, and are intended to account for the inherent variations in measured or calculated values that would be recognized by those of ordinary skill in the art.

As used herein, the term "operator" refers to a clinician, practitioner, technician or any person or machine that designs and/or manufactures an orthodontic appliance or portion thereof, and/or facilitates the design and/or manufacture of the appliance or portion thereof, and/or any person or machine associated with installing the appliance in the patient's mouth and/or any subsequent treatment of the patient associated with the appliance.

As used herein, the term "force" refers to the magnitude and/or direction of a force, a torque, or a combination thereof.

<FIG> is a schematic representation of an orthodontic appliance <NUM> (or "appliance <NUM>") configured in accordance with embodiments of the present technology, shown positioned in a patient's mouth adjacent the patient's teeth <FIG> is an enlarged view of a portion of the appliance <NUM>. The appliance <NUM> is configured to be installed within a patient's mouth to impart forces on one or more of the teeth to reposition all or some of the teeth. In some cases, the appliance <NUM> may additionally or alternatively be configured to maintain a position of one or more teeth. As shown schematically in <FIG> and <FIG>, the appliance <NUM> can comprise a deformable member that includes one or more attachment portions <NUM> (each represented schematically by a box), each configured to be secured to a tooth surface directly or indirectly via a securing member <NUM>. The appliance <NUM> may further comprise one or more connectors <NUM> (also depicted schematically), each extending directly between attachment portions <NUM> ("first connectors <NUM>"), between an attachment portion <NUM> and one or more other connectors <NUM> ("second connectors <NUM>"), or between two or more other connectors <NUM> ("third connectors <NUM>"). Only two attachment portions <NUM> and two connectors <NUM> are labeled in <FIG> for ease of illustration. As discussed herein, the number, configuration, and location of the connectors <NUM> and attachment portions <NUM> may be selected to provide a desired force on one or more of the teeth when the appliance <NUM> is installed.

The attachment portions <NUM> may be configured to be detachably coupled to a securing member <NUM> that is bonded, adhered, or otherwise secured to a surface of one of the teeth to be moved. In some embodiments, one or more of the attachment portions <NUM> may be directly bonded, adhered, or otherwise secured to a corresponding tooth without a securing member or other connection interface at the tooth. The different attachment portions <NUM> of a given appliance <NUM> may have the same or different shape, same or different size, and/or same or different configuration. The attachment portions <NUM> may comprise any of the attachment portions, bracket connectors, and/or male connector elements disclosed in <CIT>.

The appliance <NUM> may include any number of attachment portions <NUM> suitable for securely attaching the appliance <NUM> to the patient's tooth or teeth in order to achieve a desired movement. In some examples, multiple attachment portions <NUM> may be attached to a single tooth. The appliance <NUM> may include an attachment portion for every tooth, fewer attachment portions than teeth, or more attachment portions <NUM> than teeth. In these and other embodiments, the appliance <NUM> one or more of the attachment portions <NUM> may be configured to be coupled to one, two, three, four, five or more connectors <NUM>.

As previously mentioned, the connectors <NUM> may comprise one or more first connectors <NUM> that extend directly between attachment portions <NUM>. The one or more first connectors <NUM> may extend along a generally mesiodistal dimension when the appliance <NUM> is installed in the patient's mouth. In these and other embodiments, the appliance <NUM> may include one or more first connectors <NUM> that extend along a generally occlusogingival and/or buccolingual dimension when the appliance <NUM> is installed in the patient's mouth. In some embodiments, the appliance <NUM> does not include any first connectors <NUM>.

Additionally or alternatively, the connectors <NUM> may comprise one or more second connectors <NUM> that extend between one or more attachment portions <NUM> and one or more connectors <NUM>. The one or more second connectors <NUM> can extend along a generally occlusogingival dimension when the appliance <NUM> is installed in the patient's mouth. In these and other embodiments, the appliance <NUM> may include one or more second connectors <NUM> that extend along a generally mesiodistal and/or buccolingual dimension when the appliance <NUM> is installed in the patient's mouth. In some embodiments, the appliance <NUM> does not include any second connectors <NUM>. In such embodiments, the appliance <NUM> would only include first connectors <NUM> extending between attachment portions <NUM>. A second connector <NUM> and the attachment portion <NUM> to which it is attached may comprise an "arm," as used herein (such as arm <NUM> in <FIG> and <FIG>). In some embodiments, multiple second connectors <NUM> may extend from the same location along the appliance <NUM> to the same attachment portion <NUM>. In such cases, the multiple second connectors <NUM> and the attachment portion <NUM> together comprise an "arm," as used herein. The use of two or more connectors to connect two points on the appliance <NUM> enables application of a greater force (relative to a single connector connecting the same points) without increasing the strain on the individual connectors. Such a configuration is especially beneficial given the spatial constraints of the fixed displacement treatments herein.

Additionally or alternatively, the connectors <NUM> may comprise one or more third connectors <NUM> that extend between two or more other connectors <NUM>. The one or more third connectors <NUM> may extend along a generally mesiodistal dimension when the appliance <NUM> is installed in the patient's mouth. In these and other embodiments, the appliance <NUM> may include one or more third connectors <NUM> that extend along a generally occlusogingival and/or buccolingual dimension when the appliance <NUM> is installed in the patient's mouth. In some embodiments, the appliance <NUM> does not include any third connectors <NUM>. One, some, or all of the third connectors <NUM> may be positioned gingival to one, some, or all of the first connectors <NUM>. In some embodiments, the appliance <NUM> includes a single third connector <NUM> that extends along at least two adjacent teeth and provides a common attachment for two or more second connectors <NUM>. In several embodiments, the appliance <NUM> includes multiple non-contiguous third connectors <NUM>, each extending along at least two adjacent teeth.

As shown in <FIG>, in some embodiments the appliance <NUM> may be configured such that all or a portion of one, some, or all of the connectors <NUM> disposed proximate the patient's gingiva when the appliance <NUM> is installed within the patient's mouth. For example, one or more third connectors <NUM> may be configured such that all or a portion of the one or more third connectors <NUM> is positioned below the patient's gum line and adjacent to but spaced apart from the gingiva. In many cases it may be beneficial to provide a small gap (e.g., <NUM> or less) between the third connector(s) <NUM> and the patient's gingiva, as contact between the third connector(s) <NUM> (or any portion of the appliance <NUM>) and the gingiva can cause irritation and patient discomfort. In some embodiments, all or a portion of the third connector(s) <NUM> is configured to be in direct contact with the gingiva when the appliance <NUM> is disposed in the patient's mouth. Additionally or alternatively, all or a portion of one or more first connectors <NUM> and/or second connectors <NUM> may be configured to be disposed proximate the gingiva.

According to some embodiments, one or more connectors <NUM> may extend between an attachment portion <NUM> or connector <NUM> and a joint comprising (a) two or more connectors <NUM>, (b) two or more attachment portions <NUM>, or (c) at least one attachment portion <NUM> and at least one connector <NUM>. According to some embodiments, one or more connectors <NUM> may extend between a first joint comprising (a) two or more connectors <NUM>, (b) two or more attachment portions <NUM>, or (c) at least one attachment member and at least one connector <NUM>, and a second joint comprising (a) two or more connectors <NUM>, (b) two or more attachment portions <NUM>, or (c) at least one attachment portion <NUM> and at least one connector <NUM>. An example of a connector <NUM> extending between (a) a j oint between a second and third connector <NUM>, <NUM>, and (b) a joint between a second connector <NUM> and an attachment portion <NUM> is depicted schematically and labeled <NUM> in <FIG>.

Each of the connectors <NUM> may be designed to have a desired stiffness so that an individual connector <NUM> or combination of connectors <NUM> imparts a desired force on one or more of the teeth. In many cases, the force applied by a given connector <NUM> may be governed by Hooke's Law, or F = k × x, where F is the restoring force exerted by the connector <NUM>, k is the stiffness coefficient of the connector <NUM>, and x is the displacement. In the most basic example, if a connector <NUM> does not exist between two points on the appliance <NUM>, then the stiffness coefficient along that path is zero and no forces are applied. In the present case, the individual connectors <NUM> of the present technology may have varying non-zero stiffness coefficients. For example, one or more of the connectors <NUM> may be rigid (i.e., the stiffness coefficient is infinite) such that the connector <NUM> will not flex or bend between its two end points. In some embodiments, one or more of the connectors <NUM> may be "flexible" (i.e., the stiffness coefficient is non-zero and positive) such that the connector <NUM> can deform to impart (or absorb) a force on the associated tooth or teeth or other connector <NUM>.

In some embodiments it may be beneficial to include one or more rigid connectors between two or more teeth. A rigid connector <NUM> is sometimes referred to herein as a "rigid bar" or an "anchor. " Each rigid connector <NUM> may have sufficient rigidity to hold and maintain its shape and resist bending. The rigidity of the connector <NUM> can be achieved by selecting a particular shape, width, length, thickness, and/or material. Connectors <NUM> configured to be relatively rigid may be employed, for example, when the tooth to be connected to the connector <NUM> or arm is not to be moved (or moved by a limited amount) and can be used for anchorage. Molar teeth, for example, can provide good anchorage as molar teeth have larger roots than most teeth and thus require greater forces to be moved. Moreover, anchoring one or more portions of the appliance <NUM> to multiple teeth is more secure than anchoring to a single tooth. As another example, a rigid connection may be desired when moving a group of teeth relative to one or more other teeth. Consider, for instance, a case in which the patient has five teeth separated from a single tooth by a gap, and the treatment plan is to close the gap. The best course of treatment is typically to move the one tooth towards the five teeth, and not vice versa. In this case, it may be beneficial to provide one or more rigid connectors between the five teeth. For all of the foregoing reasons and many others, the appliance <NUM> may include one or more rigid first connectors <NUM>, one or more rigid second connectors <NUM>, and/or one or more rigid third connectors <NUM>.

In these and other embodiments, the appliance <NUM> may include one or more flexible first connectors <NUM>, one or more flexible second connectors <NUM>, and/or one or more flexible third connectors <NUM>. Each flexible connector <NUM> may have a particular shape, width, thickness, length, material, and/or other parameters to provide a desired degree of flexibility. According to some embodiments of the present technology, the stiffness of a given connector <NUM> may be tuned via incorporation of a one or more resiliently flexible biasing portions <NUM>. As shown schematically in <FIG>, one, some, or all of the connectors <NUM> may include one or more biasing portion <NUM>, such as springs, each configured to apply a customized force specific to the tooth to which it is attached.

As depicted in the schematic shown in <FIG>, the biasing portion(s) <NUM> may extend along all or a portion of the longitudinal axis L1 of the respective connector <NUM> (only the longitudinal axis L1 for second connector <NUM> and the longitudinal axis L2 for third connector <NUM> is labeled in <FIG>). The direction and magnitude of the force and torque applied on a tooth by a biasing portion <NUM> depends, at least in part, on the shape, width, thickness, length, material, shape set conditions, and other parameters of the biasing portion <NUM>. As such, one or more aspects of the biasing portion <NUM> (including the aforementioned parameters) may be varied so that the corresponding arm <NUM>, connector <NUM>, and/or biasing portion <NUM> produces a desired tooth movement when the appliance <NUM> is installed in the patient's mouth. Each arm <NUM> and/or biasing portion <NUM> may be designed to move one or more teeth in one, two, or all three translational directions (i.e., mesiodistal, buccolingual, and occlusogingival) and/or in one, two, or all three rotational directions (i.e., buccolingual root torque, mesiodistal angulation and mesial out-in rotation).

The biasing portions <NUM> of the present technology can have any length, width, shape, and/or size sufficient to move the respective tooth towards a desired position. In some embodiments, one, some, or all of the connectors <NUM> may have one or more inflection points along a respective biasing portion <NUM>. The connectors <NUM> and/or biasing portions <NUM> may have a serpentine configuration such that the connector <NUM> and/or biasing portion <NUM> doubles back on itself at least one or more times before extending towards the attachment portion <NUM>. For example, in some embodiments the second connectors <NUM> double back on themselves two times along the biasing portion <NUM>, thereby forming first and second concave regions facing in generally different directions relative to one another. The open loops or overlapping portions of the connector <NUM> corresponding to the biasing portion <NUM> may be disposed on either side of a plane P (<FIG>) bisecting an overall width W (<FIG>) of the arm <NUM> and/or connector <NUM> such that the extra length of the arm <NUM> and/or connector <NUM> is accommodated by the space medial and/or distal to the arm <NUM> and/or connector <NUM>. This allows the arm <NUM> and/or connector <NUM> to have a longer length (as compared to a linear arm) to accommodate greater tooth movement, despite the limited space in the occlusal-gingival or vertical dimension between any associated third connector <NUM> and the location at which the arm <NUM> attaches to the tooth.

It will be appreciated that the biasing portion <NUM> may have other shapes or configurations. For example, in some embodiments the connector <NUM> and/or biasing portion <NUM> may include one or more linear regions that zig-zag towards the attachment portion <NUM>. One, some, or all of the connectors <NUM> and/or biasing portions <NUM> may have only linear segments or regions, or may have a combination of curved and linear regions. In some embodiments, one, some, or all of the connectors <NUM> and/or biasing portions <NUM> do not include any curved portions.

According to some examples, a single connector <NUM> may have multiple biasing portions <NUM> in series along the longitudinal axis of the respective connector <NUM>. In some embodiments, multiple connectors <NUM> may extend between two points along the same or different paths. In such embodiments, the different connectors <NUM> may have the same stiffness or different stiffnesses.

In those embodiments where the appliance <NUM> has two or more connectors <NUM> with biasing portions <NUM>, some, none, or all of the connectors <NUM> may have the same or different lengths, the same or different widths, the same or different thicknesses, the same or different shapes, and/or may be made of the same or different materials, amongst other properties. In some embodiments, less than all of the connectors <NUM> have biasing portions <NUM>. Connectors <NUM> without biasing portions <NUM> may, for example, comprise one or more rigid connections between a rigid third connector <NUM> and the attachment portion <NUM>. In some embodiments, none of the connectors <NUM> of the appliance <NUM> have a biasing portion <NUM>.

According to some embodiments, for example as depicted schematically in <FIG>, the appliance <NUM> may include a single, continuous, substantially rigid third connector (referred to as "anchor <NUM>") and a plurality of flexible arms <NUM> extending away from the anchor <NUM>. When the appliance <NUM> is installed in the patient's mouth, each of the arms <NUM> may connect to a different one of the teeth to be moved and exerts a specific force on its respective tooth, thereby allowing an operator to move each tooth independently. Such a configuration provides a notable improvement over traditional braces in which all of the teeth are connected by a single archwire, such that movement of one tooth can cause unintentional movement of one or more nearby teeth. As discussed in greater detail herein, the independent and customized tooth movement enabled by the appliances of the present technology allows the operator to move the teeth from an original tooth arrangement ("OTA") to a final tooth arrangement ("FTA") more efficiently, thereby obviating periodic adjustments, reducing the number of office visits, and reducing or eliminating patient discomfort, and reducing the overall treatment time (i.e., the length of time the appliance is installed in the patient's mouth) by at least <NUM>% relative to the overall treatment time for traditional braces.

The anchor <NUM> may comprise any structure of any shape and size configured to comfortably fit within the patient's mouth and provide a common support for one or more of the arms <NUM>. In many embodiments, the anchor <NUM> is disposed proximate the patient's gingiva when the appliance <NUM> is installed within the patient's mouth, for example as shown in <FIG>. For instance, the appliance may be designed such that, when installed in the patient's mouth, all or a portion of the anchor <NUM> is positioned below the patient's gum line and adjacent but spaced apart from the gingiva. In many cases it may be beneficial to provide a small gap (e.g., <NUM> or less) between the anchor <NUM> (or any portion of the appliance <NUM>) and the patient's gingiva as contact between the anchor <NUM> and the gingiva can cause irritation and patient discomfort. In some embodiments, all or a portion of the anchor <NUM> is configured to be in contact with the gingiva when the appliance <NUM> is disposed in the patient's mouth.

The anchor <NUM> may be significantly more rigid than the arms <NUM> such that the equal and opposite forces experienced by each of the arms <NUM> when exerting a force on its respective tooth are countered by the rigidity of the anchor <NUM> and the forces applied by the other arms <NUM>, and do not meaningfully affect the forces on other teeth. As such, the anchor <NUM> effectively isolates the forces experienced by each arm <NUM> from the rest of the arms <NUM>, thereby enabling independent tooth movement.

According to some embodiments, for example as shown schematically in <FIG> and <FIG>, the anchor <NUM> comprises an elongated member having a longitudinal axis L2 (see <FIG>) and forming an arched shape configured to extend along a patient's jaw when the appliance <NUM> is installed. In these and other embodiments, the anchor <NUM> may be shaped and sized to span two or more of the patient's teeth when positioned in the patient's mouth. In some examples, the anchor <NUM> includes a rigid, linear bar, or may comprise a structure having both linear and curved segments. In these and other embodiments, the anchor <NUM> may extend laterally across all or a portion of the patient's mouth (e.g., across all or a portion of the palate, across all or a portion of the lower jaw, etc.) and/or in a generally anterior-posterior direction. Moreover, the appliance <NUM> may comprise a single anchor or multiple anchors. For example, the appliance <NUM> may comprise multiple, discrete, spaced apart anchors, each having two or more arms <NUM> extending therefrom. In these and other embodiments, the appliance <NUM> may include one or more other connectors extending between adjacent arms <NUM>.

Any and all of the features discussed above with respect to anchor <NUM> may apply to any of the third connectors <NUM> disclosed herein.

As shown in <FIG>, each of the arms <NUM> may extend between a proximal or first end portion 130a and a distal or second end portion 130b, and may have a longitudinal axis L extending between the first end portion 130a and the second end portion 130b. The first end portion 130a of one, some, or all of the arms <NUM> may be disposed at the anchor <NUM>. In some embodiments, one, some, or all of the arms <NUM> are integral with the anchor <NUM> such that the first end portion 130a of such arms are continuous with the anchor <NUM>. The arms <NUM> may extend from the anchor <NUM> at spaced intervals along the longitudinal axis L2 of the anchor <NUM>, as shown in <FIG>. In some embodiments, the arms <NUM> may be spaced at even intervals relative to each other, or at uneven intervals relative to each other, along the longitudinal axis L2 of the anchor <NUM>.

One, some, or all of the arms <NUM> may include an attachment portion <NUM> at or near the second end portion 130b. In some embodiments, for example as shown in <FIG>, one or more of the arms <NUM> is cantilevered from the anchor <NUM> such that the second end portion 130b of the cantilevered arm(s) <NUM> has a free distal end portion 130b. In these and other embodiments, a distal terminus of the attachment portion <NUM> may coincide with a distal terminus of the arm <NUM>. The attachment portion <NUM> may be configured to detachably couple the respective arm <NUM> to a securing member (e.g., a bracket) that is bonded, adhered, or otherwise secured to a surface of one of the teeth to be moved. In some embodiments, the attachment portion <NUM> may be directly bonded, adhered, or otherwise secured to a corresponding tooth without a securing member or other connection interface at the tooth.

Referring to still to <FIG> and <FIG>, one, some, or all of the arms <NUM> may include one or more resiliently flexible biasing portions <NUM>, such as springs, each configured to apply a customized force, torque or combination of force and torque specific to the tooth to which it is attached. The biasing portion(s) <NUM> may extend along all or a portion of the longitudinal axis L1 of the respective arm <NUM> between the anchor <NUM> and the attachment portion <NUM>. The direction and magnitude of the force and torque applied on a tooth by a biasing portion <NUM> depends, at least in part, on the shape, width, thickness, length, material, shape set conditions, and other parameters of the biasing portion <NUM>. As such, one or more aspects of the arm <NUM> and/or biasing portion <NUM> (including the aforementioned parameters) may be varied so that the arm <NUM> and/or biasing portion <NUM> produce a desired tooth movement when the appliance <NUM> is installed in the patient's mouth. Each arm <NUM> and/or biasing portion <NUM> may be designed to move one or more teeth in one, two, or all three translational directions (i.e., mesiodistal, buccolingual, and occlusogingival) and/or in one, two, or all three rotational directions (i.e., buccolingual root torque, mesiodistal angulation and mesial out-in rotation).

The biasing portions <NUM> of the present technology can have any length, width, shape, and/or size sufficient to move the respective tooth towards a desired FTA. In some embodiments, one, some, or all of the arms <NUM> may have one or more inflection points along a respective biasing portion <NUM>. The arms <NUM> and/or biasing portions <NUM> may have a serpentine configuration such that the arm <NUM> and/or biasing portion <NUM> doubles back on itself at least one or more times before extending towards the attachment portion <NUM>. In <FIG>, the arm <NUM> doubles back on itself two times along the biasing portion <NUM>, thereby forming first and second concave regions facing in generally different directions relative to one another. The open loops or overlapping portions of the arm <NUM> corresponding to the biasing portion <NUM> may be disposed on either side of a plane P bisecting an overall width W of the arm <NUM> such that the extra length of the arm <NUM> is accommodated by the space medial and/or distal to the arm <NUM>. This allows the arm <NUM> to have a longer length (as compared to a linear arm) to accommodate greater tooth movement, despite the limited space in the occlusal-gingival or vertical dimension between the anchor <NUM> and the location at which the arm <NUM> attaches to the tooth.

It will be appreciated that the biasing portion <NUM> may have other shapes or configurations. For example, in some embodiments the arm <NUM> and/or biasing portion <NUM> may include one or more linear regions that zig-zag towards the attachment portion <NUM>. One, some, or all of the arms <NUM> and/or biasing portions <NUM> may have only linear segments or regions, or may have a combination of curved and linear regions. In some embodiments, one, some, or all of the arms <NUM> and/or biasing portions <NUM> do not include any curved portions.

According to some examples, a single arm <NUM> may have multiple biasing portions <NUM>. The multiple biasing portions <NUM> may be in series along the longitudinal axis L1 of the respective arm <NUM>. In some embodiments, multiple arms <NUM> may extend in parallel between two points along the same path or along different paths. In such embodiments, the different arms <NUM> may have the same stiffness or different stiffnesses.

In those embodiments where the appliance <NUM> has two or more arms <NUM> with biasing portions <NUM>, some, none, or all of the arms <NUM> may have the same or different lengths, the same or different widths, the same or different thicknesses, the same or different shapes, and/or may be made of the same or different materials, amongst other properties. In some embodiments, less than all of the arms <NUM> have biasing portions <NUM>. Arms <NUM> without biasing portions <NUM> may, for example, comprise one or more rigid connections between the anchor <NUM> and the attachment portion <NUM>. In some embodiments, none of the arms <NUM> of the appliance <NUM> have a biasing portion <NUM>.

The appliances of the present technology may include any number of arms <NUM> suitable for repositioning the patient's teeth while taking into account the patient's comfort. Unless explicitly limited to a certain number of arms in the specification, the appliances of the present technology may comprise a single arm, two arms, three arms, five arms, ten arms, sixteen arms, etc. In some examples, one, some, or all of the arms <NUM> of the appliance may be configured to individually connect to more than one tooth (i.e., a single arm <NUM> may be configured to couple to two teeth at the same time). In these and other embodiments, the appliance <NUM> may include two or more arms <NUM> configured to connect to the same tooth at the same time.

Any portion of the appliances of the present technology may include a biasing portion <NUM>. For example, in some embodiments, portions thereof (e.g., the anchor(s), the arm(s), the biasing portion(s), the attachment portion(s), the link(s), etc.) may comprise one or more superelastic materials.

Additional details related to the individual directional force(s) applied via the biasing portion <NUM> or, more generally the arm <NUM>, are described in <CIT>.

The appliances disclosed herein and/or any portion thereof (e.g., the anchor(s), the arm(s), the biasing portion(s), the attachment portion(s), the link(s), etc.) may comprise one or more superelastic materials. The appliances disclosed herein and/or any portion thereof (e.g., the anchor(s), the arm(s), the biasing portion(s), the attachment portion(s), the link(s), etc.) may comprise Nitinol, stainless steel, beta-titanium, cobalt chrome, MP35N, 35N LT, one or more metal alloys, one or more polymers, one or more ceramics, and/or combinations thereof.

<FIG> are elevation views of the appliance <NUM> installed on both the upper and lower arches of a patient's mouth M with the arms <NUM> coupled to securing members <NUM> attached to the lingual surfaces of the teeth. It will be appreciated that the appliance <NUM> of one or both of the upper and lower arches may be positioned proximate a buccal side of a patient's teeth, and that the securing elements <NUM> and/or arms <NUM> may alternatively be coupled to the buccal surface of the teeth.

<FIG> shows the teeth in an OTA with the arms <NUM> in a deformed or loaded state, and <FIG> shows the teeth in the FTA with the arms <NUM> in a substantially unloaded state. When the arms <NUM> are initially secured to the securing members <NUM> when the teeth are in the OTA, the arms <NUM> are forced to take a shape or path different than their "as designed" configurations. Because of the inherent memory of the resilient biasing portions <NUM>, the arms <NUM> impart a continuous, corrective force on the teeth to move the teeth towards the FTA, which is where the biasing portions <NUM> are in their as-designed or unloaded configurations. As such, tooth repositioning using the appliances of the present technology can be accomplished in a single step, using a single appliance. In addition to enabling fewer office visits and a shorter treatment time, the appliances of the present technology greatly reduce or eliminate the pain experienced by the patient as the result of the teeth moving as compared to braces. With traditional braces, every time the orthodontist makes an adjustment (such as installing a new archwire, bending the existing archwire, repositioning a bracket, etc.), the affected teeth experience a high force which is very painful for the patient. Over time, the applied force weakens until eventually a new wire is required. The appliances of the present technology, however, apply a movement-generating force on the teeth continuously while the appliance is installed, which allows the teeth to move at a slower rate that is much less painful (if painful at all) for the patient. Even though the appliances disclosed herein apply a lower and less painful force to the teeth, because the forces being applied are continuous and the teeth can move independently (and thus more efficiently), the appliances of the present technology arrive at the FTA faster than traditional braces or aligners, as both alternatives require intermediate adjustments.

In many embodiments, the movement-generating force is lower than that applied by traditional braces. In those embodiments in which the appliance comprises a superelastic material (such as nitinol), the superelastic material behaves like a constant force spring for certain ranges of strain, and thus the force applied does not drop appreciably as the tooth moves. For example, as shown in the stress-strain curves of nitinol and steel in <FIG>, the curve for nitinol is relatively flat compared to that of steel. Thus, the superelastic connectors, biasing portions, and/or arms of the present technology apply essentially the same stress for many different levels of strain (e.g., deflection). As a result, the force applied to a given tooth stays constant as the teeth move during treatment, at least up until the teeth are very close or in the final arrangement. The appliances of the present technology are configured to apply a force just below the pain threshold, such that the appliance applies the maximum non-painful force to the tooth (or teeth) at all times during tooth movement. This results in the most efficient (i.e., fastest) tooth movement without pain.

In some embodiments, tooth repositioning may involve multiple steps performed progressively, by using multiple appliances. Embodiments involving multiple steps (or multiple appliances, or both) may include one or more intermediate tooth arrangements (ITAs) between an original tooth arrangement (OTA) and a desired final tooth arrangement (FTA). Likewise, the appliances disclosed herein may be designed to be installed after a first or subsequently used appliance had moved the teeth from an OTA to an ITA (or from one ITA to another ITA) and was subsequently removed. Thus, the appliances of the present technology may be designed to move the teeth from an ITA to an FTA (or to another ITA). Additionally or alternatively, the appliances may be designed to move the teeth from an OTA to an ITA, or from an OTA to an FTA without changing appliances at an ITA.

In some embodiments, the appliances disclosed herein may be configured such that, once installed on the patient's teeth, the appliance cannot be removed by the patient. In some embodiments, the appliance may be removable by the patient.

Any of the example appliances or appliance portions described herein may be made of any suitable material or materials, such as, but not limited to nitinol, stainless steel, beta-titanium, cobalt chrome or other metal alloy, polymers or ceramics, and may be made as a single, unitarily-formed structure or, alternatively, in multiple separately formed components connected together in single structure. However, in particular examples, the rigid bars, bracket connectors and loop or curved features of an appliance (or portion of an appliance) described in those examples are made by cutting a two dimensional (2D) form of the appliance from a 2D sheet of material and bending the 2D form into a desired 3D shape of the appliance, according to processes as described in more detail below. Additionally or alternatively, such appliances (or portions of appliances) can be formed using any suitable techniques, including those described in <CIT>.

<FIG> illustrates an example process <NUM> for designing and fabricating an orthodontic appliance as described elsewhere herein. The particular processes described herein are exemplary only, and may be modified as appropriate to achieve the desired outcome (e.g., the desired force applied to each tooth by the appliance, the desired material properties of the appliance, etc.). In various embodiments, other suitable methods or techniques can be utilized to fabricate an orthodontic appliance. Moreover, although various aspects of the methods disclosed herein refer to sequences of steps, in various embodiments the steps can be performed in different orders, two or more steps can be combined together, certain steps may be omitted, and additional steps not expressly discussed can be included in the process as desired.

As noted above, in some embodiments an orthodontic appliance is configured to be coupled to a patient's teeth while the teeth are in an original tooth arrangement (OTA). In this position, elements of the appliance exert customized loads on individual teeth to urge them toward a desired final tooth arrangement (FTA). For example, an arm <NUM> of the appliance <NUM> can be coupled to a tooth and configured to apply a force so as to urge the tooth in a desired direction toward the FTA. In one example, an arm <NUM> of the appliance <NUM> can be configured to apply a tensile force that urges the tooth lingually along the facial-lingual axis. By selecting the appropriate dimensions, shape, shape set, material properties, and other aspects of the arms <NUM>, a customized load can be applied to each tooth to move each tooth from its OTA toward its FTA. In some embodiments, the arms <NUM> are each configured such that little or no force is applied once the tooth to which the arm <NUM> is coupled has achieves its FTA. In other words, the appliance <NUM> can be configured such that the arms <NUM> are at rest in the FTA state.

As shown in <FIG>, the process <NUM> can begin at block <NUM> with obtaining data (e.g., position data) characterizing the patient's original tooth arrangement (OTA). In some embodiments, the operator may obtain a digital representation of the patient's OTA, for example using optical scanning, cone beam computed tomography (CBCT), scanning of patient impressions, or other suitable imaging technique to obtain position data of the patient's teeth, gingiva, and optionally other adjacent anatomical structures while the patient's teeth are in the original or pre-treatment condition.

The process <NUM> continues at block <NUM> with obtaining data (e.g., position data) characterizing the patient's intended or desired final tooth arrangement (FTA). The data characterizing the FTA can include coordinates (e.g., X,Y,Z coordinates) for each of the patient's teeth and the gingiva, Additionally or alternatively, such data can include positioning of each of the patient's teeth relative to other ones of the patient's teeth and/or the gingiva. In some embodiments, the operator can obtain a digital representation of the patient's FTA, for example, an FTA digital model generated using segmentation software (e.g., iROK Digital Dentistry Studio) to create individual virtual teeth and gingiva from the OTA data. In some embodiments, digital models of the securing members <NUM> can be added to the segmented OTA digital model (e.g., by an operator selecting positions on the lingual surface (or other suitable surface) for placement of securing members <NUM> thereon). Suitable software can be used to move the virtual teeth with the attached securing members <NUM> from the OTA to a desired final position (e.g., the FTA), with or without the securing members digital models included.

At block <NUM>, a heat treatment fixture digital model can be obtained. In some embodiments, the heat treatment fixture digital model can correspond to and/or be derived from the FTA digital model. For example, the FTA digital model can be modified (e.g., using MeshMixer or other suitable modeling software) in a variety of ways to render a model suitable for manufacturing a heat treatment fixture. In some embodiments, the FTA digital model can be modified to replace the securing members <NUM> (which are configured to couple to arms <NUM> of an appliance <NUM> (<FIG>)) with hook-like members (which can be configured to facilitate temporary coupling of the heat treatment fixture to the appliance for shape-setting). Additionally or alternatively, the FTA digital model can be modified to enlarge or thicken the gingiva, to remove one or more of the teeth, and/or to add structural components for increased rigidity. In some embodiments, enlarging or thickening the gingiva may be done to ensure portions (e.g., the anchor) of the fabricated appliance, which is based in part on the FTA digital model, does not engage or contact the patient's gingiva when the appliance is installed. As a result, modifying the FTA digital model as described herein may be done to provide a less painful teeth repositioning experience for the patient.

The process <NUM> continues at block <NUM> with obtaining an appliance digital model. As used herein, the term "digital model" and "model" are intended to refer to a virtual representation of an object or collection of objects. For example, the term "appliance digital model" refers to the virtual representation of the structure and geometry of the appliance, including its individual components (e.g., the anchor, arms, biasing portions, attachment portions, etc.). In some embodiments, a substantially planar digital model of the appliance is generated based at least in part on the heat treatment fixture digital model (and/or the FTA digital model). According to some examples, a contoured or 3D appliance digital model generally corresponding to the FTA can first be generated that conforms to the surface and attachment features of the heat treatment fixture digital model. In some embodiments, the 3D appliance digital model can include generic arm portions and securing members, without particular geometries, dimensions, or other properties of the arms being selected or defined by a particular patient. The 3D appliance digital model may then be flattened to generate a substantially planar or substantially 2D appliance digital model. In some embodiments, the particular configuration of the arms <NUM> (e.g., the geometry of biasing portions <NUM>, the position along the anchor <NUM> (<FIG>), etc.) can then be selected so as to apply the desired force to urge the corresponding tooth (to which the arm <NUM> is attached) from its OTA toward its FTA. As noted previously, in some embodiments the arms are configured so as to be substantially at rest or in a substantially unstressed state when at the FTA. The selected arm configurations can then be substituted or otherwise incorporated into the planar appliance digital model.

At block <NUM>, the heat treatment fixture can be fabricated. For example, using the heat treatment fixture digital model (block <NUM>), the heat treatment fixture can be cast, molded, 3D printed, or otherwise fabricated using suitable materials configured to withstand heating for shape setting of an appliance thereon.

At block <NUM>, the appliance can be fabricated. In some embodiments, fabricating the appliance includes first fabricating the appliance in a planar configuration based on the planar appliance digital model. For example, the planar appliance can be cut out of a sheet of metal or other suitable material. In some embodiments, the appliance is cut out of a sheet of Nitinol or other metal using laser cutting, water jet, stamping, chemical etching, machining, or other suitable technique. The thickness of the material can be varied across the appliance, for example by electropolishing, etching, grinding, depositing, or otherwise manipulating the material of the appliance to achieve the desired material properties.

According to some examples, the planar member (e.g., as cut out from a sheet of metal) can be bent or otherwise manipulated into the desired arrangement (e.g., substantially corresponding to the FTA) to form a contoured appliance. In some embodiments, the planar appliance can be bent into position by coupling the planar appliance to the heat treatment fixture fabricated at block <NUM>. For example, the arms of the appliance can be removably coupled to hook members of the heat treatment fixture, and optionally ligature wire or other temporary fasteners can be used to secure the arms or other portions of the appliance to the heat treatment fixture. The resulting assembly (i.e., the appliance fastened to the heat treatment fixture) can then be heated to shape-set the appliance into its final form, which can correspond or substantially correspond to the FTA. As a result, the appliance is configured to be in an unstressed, or nearly unstressed, state in the FTA. In operation, the appliance can then be installed in the patient's mouth (e.g., by bending or otherwise manipulating arms of the appliance to be coupled to brackets of the patient's teeth while in the OTA). Due to the shape set of the appliance and the geometry of the arms and anchor, the arms will tend to urge each tooth away from its OTA and toward the FTA.

Additional details and further examples of processes for designing and fabricating appliances and heat treatment fixtures are described below. The particular processes disclosed herein are exemplary, and may be modified as needed to achieve the desired outcome (e.g., the desired force applied to each tooth by the appliance, the desired material properties of the final appliance, etc.). Moreover, although various aspects of the methods disclosed herein refer to sequences of steps, in various embodiments the steps can be performed in different orders, two or more steps can be combined together, certain steps may be omitted, and additional steps not expressly discussed can be included in the process as desired.

Several of the methods disclosed herein can be performed using one or more aspects of a manufacturing system <NUM> shown schematically in <FIG>. The system <NUM> can include an imaging device <NUM> communicatively coupled to a computing device <NUM>. The imaging device <NUM> can include any suitable device or collection of devices configured to obtain image data or other digital representation of a patient's teeth, gingiva, and other dental anatomy. For example, the imaging device <NUM> can include an optical scanning device (e.g., as commercially sold by ITERO, <NUM> SHAPE, and others), a cone-beam computed tomography scanner, or any other suitable imaging device. In some embodiments, the imaging device <NUM> can be any suitable device for obtaining a digital representation of a patient's anatomy (e.g., the OTA), even if such digital representation is not based on and does not result in a graphical representation of the patient's anatomy.

The computing device <NUM> can be any suitable combination of software and hardware. For example, the computing device <NUM> can include a special purpose computer or data processor that is specifically programmed, configured, or constructed to perform one or more of the computer-executable instructions explained in detail herein. Additionally or alternatively, the computing device <NUM> can include a distributed computing environment in which tasks or modules are performed by remote processing devices, which are linked through a communication network (e.g., a wireless communication network, a wired communication network, a cellular communication network, the Internet, a short-range radio network (e.g., via Bluetooth)). In a distributed computing environment, program modules may be located in both local and remote memory storage devices.

Computer-implemented instructions, data structures, and other data under aspects of the technology may be stored or distributed on computer-readable storage media, including magnetically or optically readable computer disks, as microcode on semiconductor memory, nanotechnology memory, organic or optical memory, or other portable and/or non-transitory data storage media. In some embodiments, aspects of the technology may be distributed over the Internet or over other networks (e.g. a Bluetooth network) on a propagated signal on a propagation medium (e.g., an electromagnetic wave(s), a sound wave) over a period of time, or may be provided on any analog or digital network (packet switched, circuit switched, or other scheme).

The system <NUM> can also include one or more input devices <NUM> (e.g., touch screen, keyboard, mouse, microphone, camera, etc.) and one or more output devices <NUM> (e.g., display, speaker, etc.) coupled to the computing device <NUM>. In operation, a user can provide instructions to the computing device <NUM> and receive output from the computing device <NUM> via the input and output devices <NUM> and <NUM>.

As shown in <FIG>, the computing device <NUM> may be connected to one or more fabricating systems <NUM> (including fabricating machines) for fabricating appliances, heat treatment fixtures, and any other components thereof and associated tools, as described herein. The computing device <NUM> can be connected to the fabricating system(s) <NUM> by any suitable communication connection including, but not limited to a direct electronic connection, network connection, or the like. Alternatively, or in addition, the connection may be provided by delivery to the fabricating system <NUM> of a physical, non-transient storage medium on which data from the computing device <NUM> has been stored.

<FIG> is a flow diagram of a process <NUM> for designing an orthodontic appliance. The process <NUM> begins at block <NUM> with obtaining data characterizing an original tooth arrangement (OTA). For example, as shown in <FIG>, the OTA data can be obtained by scanning the patient's teeth using an intraoral optical scanner <NUM>. Such a scanner <NUM> can be used to scan both the patient's upper and lower teeth to generate a 3D model of each. The scanning can be performed using any suitable technique, for example a dental cone beam CT scanner, or magnetic resonance imaging (MRI), or similar device or technique. In various examples, the OTA data can include data associated with the roots of the teeth as well as the exposed portions, which may be advantageous in designing an appropriate orthodontic appliance. In some examples, the OTA data can be obtained using an impression made of the patient's upper and lower jaws (e.g., using polyvinyl siloxane or any other suitable impression material). The impression can then be scanned to create 3D data, which can include the relationship between the upper and lower jaw (e.g., to record the patient's bite). In examples in which impressions are used, the relationship between the teeth in the upper and lower arches (inter-arch relationship) can be obtained by taking a wax bite of the patient in the centric position. In various embodiments, the OTA data can be obtained directly (e.g., by imaging the patient's mouth using an appropriate imaging device) or indirectly (e.g., by receiving preexisting OTA data from an operator or another source).

Returning to <FIG>, the process <NUM> continues with obtaining an OTA digital model at block <NUM>. <FIG> is a graphical representation of an example of an OTA digital model <NUM>. The digital model <NUM> can virtually represent or characterize the arrangement of the patient's teeth and gingiva in the original tooth arrangement. As seen in <FIG>, the teeth in the OTA may be maloccluded, mis-aligned, crowded, or otherwise in need of orthodontic correction. In some embodiments, one or more teeth present in the OTA may be designated for extraction prior to use of the orthodontic appliance.

In some embodiments, obtaining the OTA digital model corresponding to the OTA data can include first obtaining a single complex 3D database of the patient's jaw, which is then segmented to separate the patient's teeth into separate 3D bodies (e.g., individual teeth or blocks of multiple teeth) that can then be manipulated virtually by an operator. Such segmentation can be performed using any suitable techniques or software, for example using iROK Digital Dentistry Studio or other suitable software. Following segmentation, the resulting 3D databases upper and lower teeth can include a model of the gingiva and independent models of each tooth. As a result, the OTA data can be manipulated by an operator to virtually move teeth relative to the gingiva. As described in more detail elsewhere herein, the teeth can be manipulated from the OTA towards a final tooth arrangement (FTA). <FIG> illustrates an example final tooth arrangement (FTA). As seen in <FIG>, the teeth in the FTA may be more aligned, less mal-occluded, and otherwise aesthetically and functionally improved relative to the OTA (e.g., as reflected in the digital model <NUM>). In some embodiments, the FTA can have desired or favorable inter-arch and intra-arch arrangements, for example, based on an operator's prescription. For example, one or more (or all) teeth from the upper or lower jaws (or both) are moved until their cusps have a good interdigitation and fit.

Referring back to <FIG>, the process <NUM> continues in block <NUM> with obtaining securing member digital model(s). As discussed previously, securing members (e.g., securing members <NUM>, brackets, etc.) can be coupled to the patient's teeth to allow for an orthodontic appliance (e.g., appliance <NUM>) to be mated thereto. The securing member digital models can include virtual representation of the geometry and/or other structural characteristics of the securing member(s). In various embodiments, the securing member digital models can be identical for each securing member, or may vary among the securing members. For example, different securing members may be used for molars than for incisors. <FIG> illustrates an example securing member digital model <NUM>.

With continued reference to <FIG>, the process <NUM> continues in block <NUM> with obtaining an OTA digital model with securing members attached. For example, the securing member digital model <NUM> (<FIG>) can be applied to appropriate locations on the patient's teeth within the OTA digital model <NUM> (<FIG>). The resulting digital model <NUM> is shown in <FIG>, in which a plurality of digital models of securing members <NUM> are disposed along lingual surfaces of the patient's teeth. In some embodiments, in the digital model <NUM>, each of the patient's teeth can have a securing member coupled thereto. As noted previously, an orthodontic appliance can include a plurality of arms having attachment portions configured to be coupled to securing members (e.g., brackets) that are attached to the patient's teeth.

In some examples, the digital models <NUM> of the securing members can be virtually positioned on the teeth in the OTA using appropriate software (e.g., iROK Digital Dentistry Studio). In some embodiments, virtually positioning the securing members can include selecting virtual models of particular securing members from a library of available securing members, and then positioning the selected securing members on one or more teeth. In some embodiments, the bracket positioning can be assigned automatically (e.g., by automatically positioning the bracket in a central or the pre-defined portion of the tooth) or manually (e.g., by an operator selecting and/or manipulating the attachment location for each securing member). In some embodiments, the position of each securing member can be refined by the operator as desired. For example, it may be desirable to position the securing members as close to the gingiva as possible so as to avoid interference with securing members on the other jaw or interference with the teeth from the other jaw when the mouth is closed.

In some embodiments, the digital model <NUM> with the teeth in the OTA and securing members attached thereto can be used to determine a configuration of a bonding tray, which may then be used to physically attach securing members to the patient's teeth by an operator. For example, the bonding tray can be configured to fit over the patient's teeth similar to an aligner, and can include recesses on a side of each tooth that are sized and configured to receive an appropriate securing member (e.g., bracket) therein. In various embodiments, such recesses can be positioned on the lingual, buccal, mesial/distal, occlusal, root, or any suitable surface of a tooth to which a corresponding bracket is intended to be bonded. In operation, an appropriate securing member can be placed in each recess and then an adhesive (e.g., an adhesive that cures when illuminated by ultraviolet light) can be applied to the bonding surface of each securing member. The tray can then be placed over the patient's teeth and the adhesive cured to bond all the securing members to the appropriate location on each tooth.

To generate such a bonding tray, the digital model <NUM> can be used, which characterizes the teeth in the OTA with securing members attached. The digital model <NUM> may be further manipulated, for example, to remove excess virtual gingiva to limit the size of the tray to only what is necessary to hold the securing members in position against the patient's teeth. The trimmed digital model can then be used to generate a physical 3D model of the patient's teeth with the securing members disposed thereon, for example using 3D printing in a polymer resin or other suitable technique.

In some embodiments, A suitable material (e.g., a clear polymer resin) can then be formed over (e.g., thermoformed over) the physical model of the patient's teeth with securing members in the OTA. This can create the aligner-like tray with recesses shaped and configured to receive securing members therein. The securing members can then be placed into corresponding recesses of the tray, and the tray can be applied to the patient's teeth with a curable adhesive to attach the securing members to the patient's teeth in the OTA. The tray may then be removed, leaving the securing members in place.

In some embodiments, the bonding tray can be 3D printed directly, without the need for a physical model of the patient's teeth and without the use of thermoforming. For example, a digital model of a bonding tray can be derived from the digital model <NUM> characterizing the teeth in the OTA with securing members attached. In some embodiments, a negative of the digital model <NUM> can be generated, and can be trimmed to provide a general tray-like structure with a surface corresponding to the teeth and securing members in the digital model <NUM>. This resulting model can be manipulated to provide features for retaining brackets in the corresponding recesses. Finally, the bonding tray can be 3D printed based on this digital model, for example using 3D printable polymer resins or other suitable materials or deposition techniques.

Alternatively, the operator may attach securing members to the patient's teeth directly, without the assistance of a tray.

Referring back to <FIG>, the process <NUM> continues at block <NUM> with obtaining an FTA digital model <NUM> (<FIG>) with securing members <NUM> attached. For example, the digital model <NUM> (<FIG>) of the teeth in OTA with models of the securing members <NUM> attached thereto can be used to generate the FTA digital model <NUM> (<FIG>). In some embodiments, the digital model <NUM> can be manipulated to place the teeth in the FTA.

The FTA digital model <NUM> can be derived based at least in part on data characterizing the teeth in the FTA. Such FTA data can include a digital representation of the desired final positions and orientations of the patient's teeth relative to one another and to the gingiva. The FTA data can be obtained directly (e.g., generated by the operator) or may be received from an external source (e.g., the FTA data may be generated by a third party and provided to an operator for design of an appropriate orthodontic appliance).

In some embodiments, the FTA data can be obtained by manipulating the OTA data to virtually move the patient's teeth. Suitable software, such as iROK Digital Dentistry Studio, can be used by an operator to move the teeth to a desired FTA. In some embodiments, virtual movement of the teeth relative to the OTA also results in movement of the gingiva relative to the OTA in order to maintain the natural look of the gingiva and more accurately reflect the orientation and position of the gingiva when the teeth are at the FTA. This movement of the gingiva can be achieved using gingiva morphing or other suitable technique.

In some embodiments, the FTA can reflect changes to the patient's teeth that may occur as part of the treatment process. For example, an operator may extract one or more teeth of the patient, due to lack of space for all the teeth to fit in the arch (or other reasons), as part of the treatment. In that event, the extracted teeth can be excluded from the FTA data. If the operator decides that the teeth need to become smaller due to a lack of space, then interproximal reduction (IPR) may be performed on the patient. In this case, stripping and reducing the size of the teeth in the FTA can be performed so as to match the IPR done by the operator.

In some embodiments, a proposed FTA can be developed by an operator (e.g., independently or based in whole or in part on input from a treating orthodontist) and then sent to a treating orthodontist for review and comment. If the treating orthodontist has comments, she can provide input to the operator (e.g., written notes, proposed manipulation of one or more teeth or securing members, etc.) that can be transmitted electronically or otherwise. The operator may then revise the FTA and send a revised proposed FTA back to the treating orthodontist for further review and comment. This iterative process may repeat until the treating orthodontist approves the proposed FTA, and the resulting digital model <NUM>.

Additionally or alternatively, an FTA digital model (e.g., as depicted in <FIG>) can be manipulated to have digital models of securing members <NUM> coupled to the teeth at appropriate locations. In some embodiments, the relative position of each securing member relative to its respective tooth may be obtained or derived from the digital model <NUM> (<FIG>), in which the securing members are attached to the teeth in the OTA. In some embodiments, the securing members may be first positioned on the teeth in the FTA to generate the digital model <NUM> (<FIG>), and this model may in turn be used to generate the digital model <NUM> (<FIG>), for example by manipulating the digital model <NUM> to move the teeth to the OTA.

Referring back to <FIG>, the process <NUM> continues at block <NUM> with determining the displacements of individual teeth or groups or teeth between the OTA and the FTA. For example, the displacement of each tooth between the OTA and FTA can be described using six degrees of freedom (e.g., translation along X, Y, and Z axes, and rotation around the same three axes; or alternatively translation along mesiodistal, buccolingual, and/or occlusogingival directions, and rotation in the form of buccolingual root torque, mesiodistal angulation, and/or mesial out-in rotation). In some embodiments, these values can be determined by calculating the difference between the location of each tooth in the FTA data and the OTA data. This can be performed for each tooth in each jaw to generate a dataset that includes the required displacement along six degrees of freedom for each tooth.

The process <NUM> continues at block <NUM> with obtaining a heat treatment fixture digital model. <FIG> illustrates an example fixture digital model <NUM>, which can be generated by manipulating the digital model <NUM> (<FIG>) of the FTA with securing members attached. For example, the digital model <NUM> can be manipulated to generate a digital representation of a fixture (e.g., a heat treatment fixture) for use in manufacturing an appliance. The digital model <NUM> can be manipulated in a number of ways to generate suitable fixture data. In some embodiments, such manipulation can be performed using suitable software, e.g. MeshMixer by Audodesk®.

In some examples, the securing members in the digital model <NUM> can be modified or substituted with appropriate securing portions <NUM> that are each configured to couple to arms of an appliance and to facilitate temporary fastening of the appliance to the fixture. For example, bracket-like securing members can be replaced with securing portions <NUM> that include both horizontal channels <NUM> configured to mate with attachment portions <NUM> of an appliance <NUM> as well as vertical channels <NUM>. A plurality of protrusions <NUM> can be disposed along one or more side surfaces of the securing portions <NUM>. Together, the channels <NUM> and <NUM> and the protrusions <NUM> can provide structures that are configured to receive ligature wire or other fastener therethrough. For example, an operator can couple an appliance <NUM> to the fixture and then wind ligature wire through the horizontal channels <NUM> and within the space between adjacent protrusions <NUM> to hold the appliance <NUM> in place against the fixture. Additionally or alternatively, the horizontal channels <NUM> can be configured to mate with attachment portions <NUM> of the appliance <NUM>, for example being sufficiently deep (e.g., deeper than corresponding channels of the securing members <NUM> of the digital model <NUM>) to both receive the attachment portions <NUM> therein and to receive ligature wire or other fastener therethrough. In some embodiments, the vertical channels <NUM> can be configured to mate with part of the attachment portions <NUM> of the appliance <NUM>, such that a single attachment portion <NUM> can be partially received within a horizontal channel <NUM> and partially received within a vertical channel <NUM>. The protrusions <NUM> may additionally define grooves or recesses configured to receive the ligature wire or other elongate fastener. The fixture model <NUM> can also define through-channels or apertures within each securing portion <NUM>. These through-channels can allow a pushing tool to be inserted from the back of the securing portion <NUM> (e.g., through the buccal surface of the fixture model <NUM>) to push an attachment portion <NUM> away from the securing portion <NUM> after the heat treatment has been completed and the ligature wire or other fastener has been removed.

Additionally or alternatively, the digital model <NUM> can be manipulated to alter the shape or configuration of the gingiva to generate the fixture model <NUM>. When an appliance is installed, a patient may suffer considerable discomfort if any portion of the appliance impinges on the gingiva. Accordingly, it can be desirable to design an appliance that rests close to the patient's gingiva without impinging upon it. In some embodiments, this can be achieved by enlarging the gingiva of the digital model <NUM> to generate the fixture model <NUM>. For example, the lingual surface of the gingiva in the digital model <NUM> can be expanded (e.g., moved more lingually) by a predetermined amount (e.g., less than about <NUM>, less than about <NUM>, less than about <NUM>, less than about <NUM>, less than about <NUM>, less than about <NUM>, less than about <NUM>, less than about <NUM>, less than about <NUM>, less than about <NUM>, less than about <NUM>, less than about <NUM> mess, less than about <NUM>, less than about <NUM>, or less than about <NUM>). As such, when an appliance is generated using the surface of the fixture data (e.g., the appliance <NUM> can be shaped to substantially correspond to a portion of the lingual surface of the fixture model <NUM>, as described in more detail below), the appliance can be sized and configured to rest a short distance away from the patient's gingiva without impinging thereon.

With continued reference to block <NUM>, the digital model <NUM> with securing members attached can be manipulated to remove the teeth or other structural elements not needed for heat treating the appliance, and/or to add structural features to reinforce the fixture for sufficient rigidity during the heat treatment process. For example, as shown in <FIG>, the fixture model <NUM> does not include any teeth, but retains at least a portion of the gingival surface <NUM>. Additionally, the fixture model <NUM> includes a stabilizing crossbar <NUM> that can enhance the rigidity of the resulting fixture. Various other modifications to the digital model <NUM> can be made to achieve the desired heat treatment fixture model <NUM>.

Referring back to <FIG>, the process <NUM> continues at block <NUM> with obtaining an appliance template digital model. <FIG> illustrates an example of an appliance template digital model <NUM>, shown here in a configuration mated with the fixture model <NUM>.

The model <NUM> defines an anchor portion <NUM>, arm portions <NUM>, and an attachment bar portion <NUM>. These components can take the form of a genericized template for an appliance that is later customized for a particular patient (as described in more detail below with respect to <FIG>). For example, the anchor portion <NUM> can correspond to the anchor <NUM> of the completed appliance, and the arm portions <NUM> can serve as placeholders for the arms <NUM> of the completed appliance. The attachment bar portion <NUM> takes the form of a continuous strip connecting each of the arms <NUM>. As shown in <FIG>, the arm portion <NUM> can be configured to be received within the channels <NUM> of the securing portions <NUM> of the fixture model <NUM>. The attachment bar portion <NUM> can correspond in part to portions of the attachment portions <NUM> of the arms <NUM> of the completed appliance.

In various embodiments, the appliance template digital model <NUM> can be generated using surface data of the fixture model <NUM>. For example, the appliance template digital model <NUM> can be configured to substantially correspond to the surface of the fixture model <NUM>, such as the anchor portion <NUM> corresponding to a contour of the fixture model <NUM> that is derived from data characterizing the patient's gingiva. As noted previously, the treatment fixture model <NUM> can be modified with respect to the OTA model <NUM> by, among other things, enlarging the gingiva. As such, when the anchor portion <NUM> contacts the gingival portion of the fixture model <NUM>, the anchor portion <NUM> may be positioned so as to be slightly spaced apart from the actual gingiva as characterized in the OTA model <NUM>. In some embodiments, the appliance template model <NUM> can have no thickness dimension, instead corresponding to a three-dimensional surface following a contour of the fixture model <NUM>. In some embodiments, the appliance template model <NUM> can have at least some thickness.

In block <NUM>, the appliance template digital model <NUM> can be flattened or otherwise manipulated to generate a planar appliance template model <NUM> (<FIG>). The planar template model <NUM> can reflect <NUM>-dimensional or substantially planar data corresponding to or at least derived from the contoured appliance template model <NUM>. For example, the appliance template digital model <NUM> (<FIG>) can be converted into the planar appliance template model <NUM> (<FIG>) by flattening, planarizing, or otherwise converting the digital model <NUM> to generate the planar appliance template model <NUM>. Such conversion may be carried out using a processor system and appropriate software such as, but not limited to ExactFlat®, Solidworks®, Autodesk® Inventor, Creo®, or other suitable software.

At block <NUM>, the planar appliance digital model is obtained. An example of a planar appliance model <NUM> is shown in <FIG>. In this stage, the particular shape and configuration of the arms of the appliance can be determined, such as by modifying or substituting portions or components of the planar template model <NUM> (<FIG>). For example, the particular dimensions, geometry, and material properties of arms of the appliance can be selected so as to apply the necessary force and/or torque to achieve the desired displacement determined at block <NUM>. In some embodiments, a pre-populated library of arm designs can be used to select an appropriate design and configuration to achieve the desired displacement. In some embodiments, the arm designs in the pre-populated library can be analyzed using finite element analysis (FEA) or other techniques to determine the spring force such arms would apply when deflected by particular amounts (e.g., the amount of deflection between the FTA (when the arm is at rest) and the OTA). In some embodiments, fully or partially automated selection of particular arm designs can be reviewed and/or modified by an operator based on relevant criteria. For example, if the proposed arm designs include overlapping or otherwise interfering arms, the operator may manually adjust the shape and/or configuration of the arms.

Based on the determined displacement, the required forces and/or torques required to move each tooth from the OTA to the FTA can be determined. The forces required to move teeth are generally in the range of centiNewtons, and distances moved are typically in the range of millimeters. The amount of moment (Newton-millimeter) acting to rotate a tooth can be found by multiplying the magnitude of the applied force by the force arm. In general, the displacement can be a 3D tooth movement that combines both translational and rotational motion.

The forces and/or torques required to achieve the FTA may depend on the patient's anatomy, for example the size of the particular tooth being moved, the anatomy of the root, etc. The forces and/or torques may also depend on other physiological parameters (e.g., bone density, biological determinants, sex, ethnicity, jaw (maxilla or mandible), mechanical properties of surrounding tissues (lips, tongue, gingiva, and bone) around the moving tooth, etc.). The particular force and/or torque applied to a given tooth will also depend on the particular positioning of the securing member (e.g., bracket). For example, a securing member positioned further off a center-of-resistance of a tooth will generate more torque under a given applied force than a securing member that is positioned nearer to a center-of-resistance of the tooth. Based on the desired displacement (e.g., along six degrees of freedom), the patient's anatomy, and the location of the securing member, a particular arm configuration can be selected to generate the desired force and/or torque on the subject tooth, so as to move the tooth from the OTA to the FTA. By determining appropriate thickness, widths, shapes, and configurations of the arms and other components of the orthodontic appliance, an appliance configuration that applies forces and torques to the appropriate teeth to move the teeth to the FTA is determined.

In particular examples, the design of the appliance may be performed by an operator, with the processor system and appropriate design software such as, but not limited to CAD software such as, but not limited to Solidworks®, Autodesk® Inventor, Creo®, or the like. FEA software such as, but not limited to Abaqus, Ansys, etc. may be employed to design the springs and arms in order to apply the desired or optimal force to the teeth. For example, such software and processing systems may be employed to design and alter the thickness, cut width, length, as well as the overall design of each arm based at least in part on the movement of the tooth to which the arm is connected.

In some examples, if a tooth needs to be displaced by a longer distance or the tooth is smaller (e.g. lower incisors), the arm <NUM> may be designed such that it is more flexible. In some embodiments, the selection or design of the arms <NUM> can account for variation in the rate of teeth movement based on direction. It is known that the rate of tooth movement when a given force is applied to the tooth is different depending on the direction of movement. For example, extrusion is the fastest movement for a given force, intrusion is the slowest, and mesiodistal and buccolingual movements are somewhere in between these two extremes. In one example, if a tooth moves <NUM> per month occlusally and <NUM> per month distally under the same applied force, the tooth will not move in a straight line as the occlusal movement will be more rapid than the distal movement. The occlusal movement will finish first, and then the tooth will move in a straight line from there in the distal direction until that motion is complete. It may be desired to move the tooth in a particular trajectory, and so the force applied distally can be different from the force applied occlusally. For example, it may be desired to move the tooth in a straight line, and so the distal force would have to be greater than the occlusal force in order to result in a straight trajectory from OTA to FTA.

In some embodiments, the arms <NUM> can be designed to impart less force on some or all of the teeth because of periodontal problems such as bone resorption, root resorption or attachment loss. The ability to customize the force or torque (or both) applied to each tooth can provide significant advantages over traditional orthodontics. In particular examples, the computer-aided procedure employs an algorithm for selecting or configuring an arm or other feature of an appliance, for example, from one or more predefined sets of options or one or more ranges of options. Thus, for example, a set of options or a range of options may be predefined for one or more parameters associated with an arm or other feature.

The one or more parameters associated with an arm <NUM> may include, but are not limited to, the overall length of the arm, the shape or configuration of the biasing portion <NUM>, the shape or configuration of the bracket connector <NUM>, the width dimension of one or more sections of the arm <NUM>, the thickness dimension of one or more sections of the arm <NUM>, or the like.

Obtaining the planar appliance digital model <NUM> can also include determining the shape and configuration of the anchor <NUM>. For example, the anchor <NUM> can be selected so as to substantially conform to the patient's gingiva without impinging thereon. The thickness, depth, or other properties of the anchor <NUM> can also be selected to provide sufficient rigidity against the forces generated by the arms. In some embodiments, the anchor <NUM> design can be automatically generated (e.g., by being automatically generated to substantially conform to the patient's gingiva or other location in the FTA model (e.g., model <NUM>) or the OTA model (e.g., model <NUM> or <NUM>). In some embodiments, an operator may manually select or revise the design and configuration of the anchor as desired.

Although in the illustrated embodiment, the specific features of the arms <NUM> are selected while the appliance model is in a substantially planar or 2D form, in other embodiments the appliance features can be selected and configured based on a digital model that is contoured to correspond to a patient's anatomy. For example, the 3D appliance template model <NUM> (<FIG>) can be modified to select particular arms <NUM>, anchor <NUM>, or any aspects thereof to achieve the desired appliance. In some embodiments, the template is omitted altogether, and a customized appliance model is generated based on the OTA model and/or the FTA model without the use of an intervening template model.

In some embodiments, the planar appliance model <NUM> can be 2D, such that the model defines no thickness of the appliance. Such a model can be used, for example, to cut an appliance out of a sheet of material. In such cases, the thickness can be determined by selecting the sheet of material and by polishing, etching, grinding, deposition, or other techniques used to modify a final thickness of the appliance. In some embodiments, the planar appliance model <NUM> can define a thickness dimension while remaining substantially planar or flat. For example, the planar appliance model <NUM> can define a thickness of the appliance which may be uniform or may vary across some or all of the anchor <NUM> and arms <NUM>.

In some embodiments, a 3D or contoured appliance model can be generated, for example by manipulating the planar appliance model <NUM> into a curved or contoured configuration. In some embodiments, the 3D appliance model can correspond to the appliance mounted to the teeth in the OTA (e.g., by manipulating the planar appliance model <NUM> using position data of the securing members <NUM> in the OTA model <NUM> (<FIG>), or by manipulating the planar appliance model <NUM> using position data of the securing members <NUM> in the FTA model <NUM> (<FIG>)).

With reference to blocks <NUM>, <NUM>, and <NUM> together, in some examples a computer-aided procedure can be used to select or determine the shape and configuration of the arms, anchor, and/or any other features of an appliance. The procedure may be configured to select one (or more than one) arm, securing member, anchor, or parameter thereof, or any other aspect of the appliance based on one or more input data. For example, input data may include, but is not limited to, a type of a tooth (e.g., molar, canine, incisor, etc.) or a size of a tooth. A larger tooth (such as a molar) may require larger arms or larger, wider or thicker loop or curved features for providing a greater force, than for a smaller tooth (such as an incisor). Additionally or alternatively, input data may include the size of the periodontal ligament (PDL) of one or more teeth. The size of the PDL may be obtained by any suitable process including, but not limited to, CBCT scan or other imaging technique. Other input data may include, but is not limited to, the number or direction of forces to be applied to a tooth or teeth in a three-dimensional space. For example, a desired tooth movement direction may require one or more shapes or configurations of arms that differ from the shapes or configurations required for a different tooth movement direction. Other input data may include but is not limited to, the number or direction of rotational forces (or torque) to be applied to a tooth or teeth. For example, a desired tooth movement in a rotational direction may require one or more shapes or configurations of arms that differ from the shapes or configurations required for a different tooth movement direction. Additionally, in some embodiments two or more arms can be attached to a single tooth, either with each arm coupled to a separate securing member, or with two arms coupled to the same securing member. In such instances, the input data can include a number of arms and/or securing members coupled to each tooth, or alternatively the number of arms and/or securing members can be generated as output data.

In some embodiments, this computer-aided procedure can include an algorithm that includes, as input, (but is not limited to) one or more values representing one or more of: (a) up to three translational and up to three rotational movements from an OTA to an ITA or FTA, or from an ITA to another ITA or FTA; (b) the surface of periodontal ligament (PDL) or the area of the root of a or each tooth; (c) bone density of the patient; (d) biological determinants for example, obtained from saliva, gingival fluid (GCF), blood, urine, mucosa, or other sources; (e) gender of the patient; (f) ethnicity of the patient; (g) the j aw (maxilla or mandible) for which the appliance is to be installed; (i) the number of teeth on which the appliance is to be installed; and (j) mechanical properties of the tissue (lips, tongue, gingiva) and bone around the teeth to be moved. In various embodiments, one or more of such inputs can affect the forces (e.g., magnitude, direction, point of contact) required to move each tooth from the OTA to or toward the FTA.

In other examples, other suitable input data may be employed. The computer-aided process employs a computer programed or configured with suitable non-transient software, hardware, firmware, or combinations thereof, to generate an output (such as one or more selected arm configurations, anchor configurations, or securing member configurations), based on the one or more input data.

An output generated by the computer-aided procedure, based on such input, can include, but is not limited to one or more of: (a) a design of an arm; (b) a width or cut-width of one or more of such arms; (c) a thickness dimension of any portion of the appliance of the entire appliance; (d) mechanical properties of such arms including but not limited to amount of flexibility, or a magnitude of bias force or resilience; (e) a design of an anchor; (f) a width or thickness of the anchor; (g) connection locations between the arms and the anchor; and/or (h) transformational temperature of the nitinol (or other material) in one or more (or each) section of the appliance. As noted previously, in some embodiments the output can include particular configurations selected from among a pre-populated library of anchors and/or arms. For example, based on the inputs, a desired force (e.g., magnitude and direction) can be determined for each tooth. Based on the desired force, an appropriate anchor member and/or arm configuration can be selected that provides the desired force or a suitable approximation thereof. In some embodiments, the configuration of the appliance (including any of the outputs listed above) can be generated independently of any pre-populated library. In some embodiments, generating the output can include analyzing provisional selections or designs using finite element analysis (FEA) or other techniques to determine performance parameters, for example, the spring force such arms would apply when deflected by particular amounts (e.g., the amount of deflection between the FTA (when the arm is at rest) and the OTA).

In particular examples, computer-aided processes can be employed to make customized appliances, for each given patient. In other examples, appliances may be made in a plurality of predefined sizes, shapes, configurations, or the like, based on a population group. Accordingly, a different semi-customized size, shape or configuration would be configured to fit each different selected portion of the population group. In that manner, a more limited number of different appliance sizes, shapes and configurations may be made to accommodate a relatively large portion of the population.

Based on the determined shape and configuration of the arms and the anchor, the full appliance shape data can be generated. In some embodiments, the appliance shape data can take the form of 3D data (e.g., the appliance in its shape-set form following heat treatment or other suitable setting technique) or planar or substantially 2D data (e.g., the appliance in its laid-flat form, for example as cut out from a sheet of material).

At block <NUM>, an appliance can be fabricated (e.g., based on the planar appliance digital model <NUM> (block <NUM>). And at block <NUM>, a heat treatment fixture can be fabricated (e.g., based on the heat treatment fixture digital model <NUM> (block <NUM>). Fabrication of the heat treatment fixture and the appliance are described in more detail below.

In some embodiments, generating the full appliance shape data can include obtaining a heat treatment fixture model (e.g., as described below with respect to <FIG>), and generating a preliminary appliance model based on the heat treatment fixture model. For example, the preliminary appliance model can conform to at least a portion of a lingual surface of the heat treatment fixture model. The preliminary appliance model can then be modified to include the determined arms and anchor, to have a determined thickness profile, etc. The modified appliance model may then be flattened for use in fabrication as described below.

As noted above, one or more digital models can be generated that characterize or define an appliance (e.g., the planar appliance digital model <NUM>, or a contoured appliance digital model). In various embodiments, one or more such digital models can be used to fabricate an appliance for use in a patient. <FIG> illustrates an example of an appliance <NUM> fabricated using one or more of the digital models described herein. Certain example fabrication processes are described below. However, one of skill in the art will appreciate that any suitable fabrication process may be used to manufacture appliances (or components thereof) as disclosed herein.

In some embodiments, an orthodontic appliance <NUM> can be fabricated using a planar digital appliance model (e.g., the planar appliance digital model <NUM>). For example, the planar appliance digital model can include planar or substantially 2D shape data. The planar shape data can be provided to a suitable fabrication device (such as, but not limited to one or more machines that perform cutting, laser cutting, milling, chemical etching, wire electrical discharge machining (EDM), water jetting, punching (stamping), etc.) for cutting a flat sheet of material into a member having a shape corresponding to the planar appliance digital model <NUM>. The member may be cut from a flat sheet of any suitable material, such as, but not limited to Nitinol, stainless steel, cobalt chrome, or another type of metal, a polymer, a superelastic material, etc. The sheet of material can have a thickness selected to achieve the desired material properties of the resulting member. In various embodiments, the thickness of the sheet of material can be uniform or can vary (e.g., along a gradient, being thinned at particular regions using etching, grinding, etc., or thickened at particular regions using deposition, etc.). In some examples, the sheet can have a thickness of between about <NUM> and about <NUM>, between about <NUM> and about <NUM>, between about <NUM> and about <NUM>, between about <NUM> and about <NUM>, or about <NUM>. In some embodiments, the sheet can have a thickness of less than about <NUM>, less than about <NUM>, less than about <NUM>, less than about <NUM>, less than about <NUM>, less than about <NUM>, less than about <NUM>, less than about <NUM>, less than about <NUM>, less than about <NUM>, less than about <NUM>, less than about <NUM>, less than about <NUM>, less than about <NUM>, or less than about <NUM>.

Next, the cut member can be bent from its substantially planar form into a contoured arrangement. <FIG> illustrates an example of a completed appliance <NUM> resulting from such bending of a planar member. As illustrated, and as described elsewhere herein, the appliance <NUM> can include an anchor <NUM> and a plurality of arms <NUM> extending away from the anchor <NUM>. Each arm <NUM> can include an attachment portion <NUM> configured to mate with a securing member adhered to a patient's tooth, and a biasing portion <NUM> disposed between the attachment portion <NUM> and the anchor <NUM>. When the appliance <NUM> is installed in the patient's mouth, each of the arms <NUM> can connect to a different one of the teeth to be moved and exerts a specific force on its respective tooth, thereby allowing an operator to move each tooth independently.

In some embodiments, the planar member, after being cut from a sheet or otherwise formed, may be bent or otherwise manipulated into a shape or contour corresponding or substantially corresponding to the FTA configuration. For example, the member can be a shape cut from a flat sheet of Nitinol or other suitable material and assume a generally planar configuration. The member can be bent into a desired 3D or contoured configuration, for example corresponding to the contoured appliance digital model <NUM>. In certain examples, one or more fixtures are configured for use in bending the planar member into the desired 3D shape. In such examples, after cutting the planar member, the planar member can be fixed on or between one or more fixtures and bent or otherwise manipulated to form a desired 3D shape. In some embodiments, either before or after cutting the member from the sheet, the thickness of the member can be modified at least in some portions to achieve desired material properties. For example, the thickness of the member can be reduced in at least some regions using grinding, chemical etching, photoetching, electrical discharge machining, or any other suitable material removal process. The thickness of the member can be increased in at least some regions using thin film deposition, electroplating, or any other suitable additive technique. In some embodiments, the planar member can be formed using 3D printing or other technique instead of or in addition to cutting the planar member from a sheet of material. 3D printing may provide certain advantages, for example ease of controlling the thickness of different portions of the appliance. In some embodiments, the planar member can be formed by 3D printing metal, a polymer, or any other suitable material amendable to additive manufacturing by 3D printing.

In some embodiments, the appliance can be shape set into the desired contoured or 3D configuration (e.g., corresponding to the FTA). One or more shape setting procedures, such as, but not limited to heat treatment, may be applied to the appliance while held in the desired 3D shape, during or after the bending operation, to set the desired 3D shape. A shape setting procedure involving a heat treatment may include rapid cooling, following heating of the member during or after bending. Additional details regarding example heat treatment and associated fixtures are described below.

By employing a cut planar member, instead of a traditional single-diameter wire, a greater variety of resulting 3D shapes may be made, as compared to shapes made by bending single-diameter wire. The cut planar member may have designed or varying widths and lengths that, when bent into a desired shape, can result in portions of the 3D appliance having variances in thickness, width and length dimensions. In this manner, the planar member can be cut into a shape that provides a desired thickness, width and length of biasing portions, arms, or other components of the appliance. A larger variety of shapes may be provided by bending a custom cut planar member, as compared to bending a single-diameter wire.

In some examples, the entire appliance (including arms and anchor) is fabricated by bending the cut planar member into the desired 3D shaped member. In other examples, additional components may be attached to the 3D shape, for example, after bending. Such additional components may include, but are not limited to attachment portions <NUM>, biasing portions <NUM>, arms <NUM>, etc. Such additional components may be attached to the 3D shaped member by any suitable attachment mechanism including, but not limited to, adhesive material, welding, friction fitting, etc..

In some embodiments, the appliance can be 3D printed directly into the desired contoured or 3D shaped configuration. In some embodiments, the 3D shaped member can be 3D printed, for example using any suitable material. In cases in which the appliance is 3D printed using Nitinol, there may be no need for a shape-setting process (e.g., heat treatment). Additionally, 3D printing may allow the use of different geometries (e.g., a cross-sectional shape of the anchor member may be oval, rather than rectangular, which may increase patient comfort on both the gingival-facing and lingual-facing sides of the anchor).

As noted previously, in some embodiments a heat treatment fixture model (e.g., the heat treatment fixture model <NUM> (<FIG>)) can be used to generate an appliance digital model. For example, the planar appliance digital model <NUM> can be obtained based at least in part on the heat treatment fixture model <NUM>. The heat treatment fixture model <NUM> may also be used to manufacture a heat treatment fixture, which is then used to shape-set the appliance (e.g., a planar member cut from a sheet of material can be formed into the desired 3D shape by use of the heat treatment fixture).

<FIG> illustrates an example of a heat treatment fixture <NUM>. The fixture <NUM> can be manufactured based on the heat treatment fixture digital model (e.g., the fixture digital model <NUM> (<FIG>)). For example, the digital model or associated data can be provided to a fabricating system to produce a physical model based on the fixture model. In one example, the fixture data can be used to 3D print a model of the fixture in wax. The wax model may then be used to investment cast the fixture in brass or other suitable material. In some embodiments, the fixture can be 3D printed directly in brass or other suitable material (e.g., stainless steel, bronze, a ceramic or other material that tolerates high temperatures required for heat treatment). As shown in <FIG>, the fixture <NUM> can include securing portions <NUM> configured to mate with attachment portions <NUM> of an appliance <NUM>.

In some embodiments, the fabricated fixture may be used to heat set an appliance. For example, as shown in <FIG>, a combined assembly <NUM> can include an appliance <NUM> that has been bent or otherwise manipulated into shape against a surface of the heat treatment fixture <NUM>. The appliance <NUM> can be coupled to the fixture <NUM> by placing attachment portions of the arms into the securing portions <NUM> of the fixture. Ligature wires <NUM> or other suitable fasteners can be wrapped around the appliance <NUM> at a plurality of positions to secure the appliance <NUM> with respect to the fixture <NUM>. Next, heat can be applied to heat set the appliance <NUM>, after which the appliance <NUM> can be removed from the fixture <NUM>.

One example, of a heat treatment procedure can include heating the appliance <NUM> to a selected temperature (such as, but not limited to <NUM> degrees centigrade) for a selected period of time (such as, but not limited to <NUM> minutes), followed by rapid cooling. The rapid cooling can be achieved by any suitable cooling procedure such as, but not limited to water quench or air-cooling. In other examples, the time and temperature for heat treatment can be different than those discussed above, for example, based upon the specific treatment plan. For example, heat treatment temperatures can be within a range from <NUM> degrees centigrade to <NUM> degrees centigrade and the time of heat treatment can be a time in the range up to about one hundred and twenty minutes. In particular examples, the heat treatment procedure may be carried out in an air or vacuum furnace, salt bath, fluidized sand bed or other suitable system. After completing the heat treatment, the appliance has a desired 3D shape and configuration (e.g., corresponding substantially to the heat treatment fixture and/or to the desired FTA). In other examples, other suitable heat-treating procedures may be employed including, but not limited to resistive heating or heating by running a current though the metal of the appliance structure.

One or more additional post processing operations may be provided on the 3D shaped article, including, but not limited to abrasive grit blasting, shot peening, polishing, chemical etching, electropolishing, electroplating, coating, ultrasonic cleansing, sterilizing or other cleaning or decontamination procedures.

In examples in which the appliance is made of multiple components, some (or each) of the components of the appliance may be made according to methods described above, and then connected together to form the desired 3D appliance configuration. In these or other examples, the appliance (or some or each component of the appliance) may be made in other suitable methods including, but not limited to: directly printing of metal, first printing of a wax member and then investment casting the wax member into a metal or other material, printing of elastomeric material or other polymer, cutting or machining out of solid material, or cutting the components out of a sheet of metal and shape setting into the desired 3D configuration.

As discussed herein, one or more heat treatment fixtures may be configured for use in bending a cut planar member into a desired 3D shape configuration. In particular examples, one or more heat treatment fixture is provided (such as, but not limited to, custom made) for each jaw of a patient. For example, the heat treatment fixtures may be customized in shape and configuration for each patient and can be made in any suitable manner, including molding, machining, direct metal printing of stainless steel or other suitable metals, 3D printing of a suitable material, such as, but not limited to stainless steel via powder bed fusion, or a steel/copper mix via binder jetting, as well as first printing the configuration in wax and then investment casting the wax into various metals. In various examples described herein, the heat treatment fixtures may be configured of material that is sufficiently resistant to the temperature of the heat treatment. In particular examples, one or more robots may be employed with or without the one or more heat treatment fixtures, for bending the cut planar member into a desired 3D shape configuration.

In some embodiments, a single shape-setting step may be completed to deform the member from its planar configuration to its desired 3D configuration. However, in certain embodiments the shape setting may include two or more shape-setting steps (e.g., two or more heat treatment processes, potentially using two or more different heat treatment fixtures). In such cases, the amount of deformation imparted to the appliance within each shape-setting step may be limited, with each subsequent shape-setting step moving the appliance further toward the desired 3D configuration.

The completed appliances can then be sent (optionally along with bonding trays and/or securing members) to the treating clinician. To install the appliances, the orthodontist can clean the lingual side of the patient's teeth to prepare them for bonding (e.g., with pumice powder). The surface of the teeth can then be sandblasted (e.g., with <NUM>-micron aluminum oxide). The securing members can then be attached using a bonding tray as described elsewhere herein.

After the appliances are fabricated and the securing members are attached to the teeth, each arm can be coupled to its corresponding securing member element to install the appliance. Once installed, the appliance imparts forces and torques on the teeth, to move the teeth to the desired FTA. After treatment is completed (e.g., OTA to FTA, OTA to ITA, ITA to ITA, or ITA to FTA) the arms may sit passively in the securing members and force will no longer be applied to the teeth. Alternatively, any remaining force applied by the arms may fall below a threshold for causing further displacement of the teeth.

The patient can return for a check-up appointment (e.g., at approximately <NUM>-<NUM> months), and if the treatment is advancing as planned, nothing is done until the patient returns at a planned time for appliance removal. At this stage the securing members may be removed. If treatment is not progressing as planned, the appliance may be removed, the patient's mouth rescanned, and a new appliance can be device designed and installed based on a modified treatment plan.

Claim 1:
A method for obtaining a digital model of a heat treatment fixture for fabricating an orthodontic appliance, comprising:
obtaining original tooth arrangement (OTA) data representing a patient's gingiva and teeth in the OTA;
obtaining final tooth arrangement (FTA) data representing the patient's gingiva and teeth in the FTA; and
obtaining a digital model of a heat treatment fixture (<NUM>) based on the OTA and FTA data, the digital model comprising (a) a gingival surface (<NUM>), and (b) a securing portion (<NUM>) characterizing a position of one or more of the patient's teeth in the FTA, wherein the heat treatment fixture (<NUM>) is configured to be releasably secured to an orthodontic appliance configured to move the patient's teeth from the OTA to the FTA such that the orthodontic appliance has a shape based at least in part on a shape of the heat treatment fixture (<NUM>).