Method of manufacturing an orthodontic appliance and system for manufacturing an orthodontic appliance

Abstract

A method of manufacturing an orthodontic appliance, the method comprising collecting a digital representation of an initial arrangement of at least a subset of adjacent teeth in a patient's jaw, and manufacturing the orthodontic appliance to cover the subset of teeth. The method comprises: (a) collecting a digital representation of an initial arrangement of at least a subset of adjacent teeth in a patient's jaw; (b) formulating a treatment plan, the treatment plan comprising at least one arrangement of the subset of teeth; and (c) manufacturing the orthodontic appliance based on the subset of adjacent teeth for the at least one arrangement. The appliance covers only the subset of teeth.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an orthodontic appliance, the method comprising: collecting a digital representation of the initial arrangement of teeth in a patient's jawbone, developing a treatment plan, preparing a mold, and forming the orthodontic appliance on the mold.

[0002] The present invention also relates to a system for manufacturing orthodontic appliances, the system comprising an imaging device, a processing device, and a manufacturing device. Background Technology

[0003] Invisible aligners are orthodontic devices that are transparent, plastic braces used to adjust the posture (position and / or orientation) of teeth.

[0004] Treatment with orthodontic appliances typically begins by capturing information about the patient's bite, teeth, and gums through occlusal recordings and physical impressions (e.g., polyvinylsiloxane impressions) or an intraoral digital scanner. The latter method has become increasingly popular due to advancements in digital scanning technology. Scanning dental impressions is to create a digital 3D representation of the teeth. In this digital representation, the target teeth (i.e., the teeth that are moved using the appliances) are moved to the desired posture. Since each appliance can move a tooth by 0.25 to 0.33 millimeters, six or more appliances may be required.

[0005] The purpose of this invention is to provide an improved orthodontic appliance. Summary of the Invention

[0006] The subject matter of the independent claim addresses the technical objective. The dependent claims define alternative embodiments of the invention.

[0007] The present invention generally relates to the manufacture of orthodontic appliances, including collecting a digital representation of an initial arrangement of at least a subset of adjacent teeth in a patient’s jawbone, and manufacturing the orthodontic appliance covering said subset of teeth.

[0008] A method for manufacturing an orthodontic appliance includes steps a), b), and c). Step a) involves collecting a digital representation of an initial arrangement of at least a subset of adjacent teeth in a patient's jawbone. Step b) involves developing a treatment plan that includes at least one arrangement for the subset of teeth. The treatment plan aims to move one or more target teeth selected from the subset of teeth from the initial arrangement to the final arrangement. Step c) includes manufacturing an orthodontic appliance for at least one arrangement based on the adjacent subset of teeth. The appliance covers (only) the subset of teeth.

[0009] In an alternative implementation, step c) includes steps c1) and / or c2). Step c1) includes preparing a mold associated with at least a subset of adjacent teeth for at least one arrangement. Step c2) includes forming an orthodontic appliance on the mold. The appliance covers the subset of teeth.

[0010] A system for manufacturing orthodontic appliances includes an imaging device, a processing device, and a manufacturing device. The imaging device is configured to image at least a subset of adjacent teeth in a patient's jawbone and / or a casting of a subset of adjacent teeth in a patient's jawbone. The processing device is electronically coupled to the imaging device. The processing device is configured to generate a digital representation of an initial arrangement of the tooth subset. The processing device is also configured to develop a treatment plan that includes at least one arrangement of the tooth subset. The treatment plan aims to move one or more target teeth in the tooth subset from the initial arrangement to a final arrangement. The manufacturing device is electronically coupled to the processing device. The manufacturing device is also configured to prepare a mold associated with at least a subset of adjacent teeth for at least one arrangement. Alternatively or additionally, the manufacturing device is configured to directly fabricate the orthodontic appliance.

[0011] Orthodontic appliances can be transparent, comprising clear, plastic aligners, used to adjust the posture (position and / or orientation) of target teeth. Orthodontic appliances may be metal-free and / or removable from the teeth. In other words, orthodontic appliances can be worn during certain times of the day (e.g., at night) and removed during other times of the day (e.g., while eating). The method of using the orthodontic appliance of this invention is similar to the method of using conventionally known clear aligners.

[0012] The orthodontic appliance of this invention differs from conventionally known clear aligners in that it can be considered a partial appliance, covering only a subset of teeth, while conventionally known clear aligners are designed to cover the entire mandible and / or maxilla (mandibular and / or maxillary dentition) down to the posterior molars. This requires obtaining impressions of the entire dentition (using an intraoral digital scanner or physical impressions), which then serve as the basis for a digital treatment plan; that is, determining the target dentition (the expected final posture (position and / or orientation) of all teeth) and the different intermediate stages / steps for progressively moving the teeth to that target.

[0013] The orthodontic appliance of this invention does not cover all the teeth in the patient's jawbone, but only a subset of the teeth. For example, the number of target teeth (i.e., the teeth that need to be moved by the appliance) is less than the number of the subset of teeth, and the number of the subset of teeth is less than the total number of teeth in the patient's jawbone.

[0014] Some potential advantages of the partial orthodontic appliance method of the present invention are: Partial braces are likely to be more comfortable to wear and therefore more readily accepted by patients. Predictably, since they only cover a portion of the entire dental arch / teeth (i.e., a subset of teeth), the interference with the patient will be relatively small. If only the posterior teeth need to be moved, and the braces only cover the molars and premolars, the braces will be almost invisible and likely have little impact on speech.

[0015] The manufacturing cost of partial orthodontic appliances can be lower. A significant portion of the total cost of providing an orthodontic appliance is the cost of manufacturing the appliance itself based on a digital treatment plan mold / model. This can involve the 3D printing time required to manufacture the mold, the cost of 3D printing materials, the cost of the appliance material discs / sheets used to vacuum / thermoform the appliance onto the mold, and the time / cost of manually or automatically trimming the appliance. Compared to full-arch appliances (in terms of the required mold), appliances with eight or ten anterior teeth have a significantly reduced platform and volume, which can significantly reduce material usage and allow for printing more appliance stages or molds per build. This could potentially reduce manufacturing time per appliance by 65% ​​and material cost per appliance by 64% in the case discussed. Furthermore, shorter / partial arch appliances are less likely to require support structures, reducing the ancillary cost of materials and requiring less effort and time to remove support structures. Shorter / partial arch appliances may also require less appliance material; more appliances should be able to be vacuum-formed with the same sheet size.

[0016] Localized orthodontic appliances can simplify impression taking. Since the appliance only covers a portion of the teeth throughout the treatment plan, only localized impressions of the patient's oral tissues covering those teeth are needed. If the appliances cover only the front eight or ten teeth, this can further enable the use of traditional imaging devices (such as cameras or smartphone cameras) or less invasive local physical impression trays to take impressions without professional intervention, as these teeth are less difficult to scan than molars. In fact, self-scanning is even possible, which can significantly reduce the overall cost of the procedure. The treatment process may produce localized appliances that can be manufactured using additive manufacturing techniques such as 3D printing.

[0017] Orthodontic appliances are designed to move target teeth, that is, one or more teeth in a subset of teeth. This movement causes a change in the orientation of the target teeth. Orthodontic orientation includes the position and / or orientation of the target teeth. Appliances can achieve lateral movement, tilting (inclination), lateral tilting (deviation), and / or rotation. For example, the target teeth may first be moved laterally to provide space for tilting / lateral tilting / rotation of a specific tooth within the target set.

[0018] The digital representation can be a dataset that, after processing, can generate a 3D image that can be displayed to the patient and / or the person treating the patient, such as a dentist or orthodontist.

[0019] This processing can be performed by a processing device, which may include a display or screen. The processing device may include a computer or other electronic processing device for analyzing a dataset indicating the initial arrangement of a subset of teeth.

[0020] The processing device is electronically coupled to the imaging device and the manufacturing device. This electronic coupling enables data transmission and / or data exchange between the processing device, the imaging device, and / or the manufacturing device. For example, the processing device, the imaging device, and / or the manufacturing device are electronically coupled via wireless connection, LAN connection, and / or the Internet. The imaging device and processing device may be located within a dental operating room or orthodontic clinic, while the manufacturing device may be located remotely.

[0021] An imaging device is any device capable of imaging a subset of teeth in a patient's oral cavity, a model of a patient's teeth, or a casting. An imaging device may be configured to image the patient's jawbone or all teeth in the patient's upper and lower jaws. An imaging device may also be configured to further image the patient's occlusion and / or gingiva. An imaging device may include optical sensors for converting visual information of light reflected from the teeth / gingiva into electronic information (e.g., a dataset). An imaging device may include optical components (e.g., lenses) for focusing a light beam from the teeth / gingiva onto the optical sensors.

[0022] The manufacturing apparatus is configured to manufacture or generate a physical model of a subset or all of the teeth in a single or double jaw of a patient. The manufacturing apparatus may include means for performing rapid prototyping (such as 3D printing and / or stereolithography). The manufacturing apparatus may also include a milling machine for milling the model or mold of the tooth subset.

[0023] Molds or models are used to manufacture orthodontic appliances. This can be done by molding the orthodontic appliance onto a model or mold. Disks / sheets of appliance material can be vacuum-formed / thermoformed onto a mold / model to manufacture the appliance.

[0024] The initial alignment of a subset of teeth includes the posture (i.e., position and / or orientation) of each tooth in the subset. Therefore, the initial alignment includes the posture of the target teeth, which will be altered by wearing orthodontic appliances.

[0025] The final arrangement includes the posture of each tooth in a subset of teeth, where the target teeth are in the desired position, and the non-target teeth have the same posture in the final arrangement as in the initial arrangement. This means that the posture of the target teeth in the final arrangement differs from that in the initial arrangement. This change in the posture of the target teeth can be achieved virtually, i.e., using a digital representation of the final arrangement. For example, the processing device includes an input device for selectively changing the posture of each target tooth. Alternatively or additionally, software simulation can also be used to generate the final arrangement based on the initial arrangement. The patient can be consulted to finalize the tooth arrangement, particularly the final arrangement of the target teeth.

[0026] An orthodontic appliance can move the target tooth by 0.25 to 0.33 millimeters. Therefore, one appliance may not be sufficient to move a subset of teeth from the initial alignment to the final alignment. More precisely, intermediate alignments between the initial and final alignments may be required. These intermediate alignments can be automatically calculated using software or algorithms by a processing device, which essentially divides the movement of the target teeth into one or more steps or intermediate alignments. The treatment plan includes the initial alignment, no alignment, one or more intermediate alignments, and the final alignment. Intermediate alignments include the posture of the target teeth, where the corresponding posture lies between the corresponding posture in the initial alignment and the corresponding posture in the final alignment.

[0027] Each appliance corresponds to a specific intermediate or final alignment. Therefore, the target teeth move progressively with each appliance. The treatment plan involves the generation of intermediate and final alignments. Furthermore, the treatment plan may also involve the timeframe for the patient to fabricate and wear the appliances associated with each intermediate or final alignment.

[0028] The initial arrangement, intermediate arrangement, and / or final arrangement may include a subset or more teeth in the patient's jawbone, such as all teeth in the patient's jawbone.

[0029] Teeth in a subset of teeth are adjacent teeth; for example, each tooth in a subset of teeth is in contact with its neighboring teeth. However, a subset of teeth can also cover multiple teeth arranged in a row in the jawbone, with one or more teeth missing. Nevertheless, a subset of teeth does not refer to randomly selected teeth in a patient's jawbone. Instead, a subset of teeth can be covered by a single orthodontic appliance, ensuring that the appliance does not cover teeth that do not belong to a subset of teeth.

[0030] Two or more local appliances can also be fabricated using a single digital representation of the teeth, a single treatment plan, and / or a single mold. For example, two local appliances can be used simultaneously for each jawbone: one on the left molars and premolars, and another on the right. In this case, the digital representation and / or mold can include more teeth than two or more subsets of teeth. For example, the digital representation and mold can include all the teeth of the jawbone.

[0031] For example, one or more molds or models are manufactured using a manufacturing apparatus, each mold or model corresponding to a specific one in the intermediate and / or final arrangement. The mold includes at least a subset of teeth; alternatively, the mold includes only a subset of teeth. Thus, the number and type of teeth in the mold correspond to the teeth in the patient's jawbone that will be covered by the orthodontic appliance to be made. However, the mold or model may also include all the teeth of the jawbone. Furthermore, the mold or model may also include the patient's upper and lower jaws.

[0032] After the treatment plan is completed, molds or models corresponding to one of the intermediate and / or final arrangements can be manufactured in one go. Alternatively, a model or mold corresponding to the first intermediate arrangement can be manufactured. After wearing the appliance corresponding to the first intermediate arrangement, steps a) through c) are repeated. In this embodiment, only one mold corresponding to the next arrangement can be manufactured in step c1), or (more generally), only one appliance can be manufactured in step c).

[0033] The mold or model manufactured in step c1) contains the poses of the target tooth, which are different from the corresponding poses of the target tooth in the initial position, thereby realizing the movement of the target tooth.

[0034] Orthodontic appliances are manufactured using molds or models, for example, employing known techniques. The appliance is manufactured by vacuum / thermoforming a disc / sheet of appliance material onto a mold or model. Thus, the appliance provides a cavity for accommodating a subset of teeth, the shape of which deviates from the shape of the cavity formed by physically taking an impression of the patient's jawbone and teeth. This deviation is intentional in order to allow for the movement of the target teeth. Once the target teeth have moved (i.e., reached their respective postures according to intermediate or final orthodontic treatment, upon which the appliance is made), the cavity shape of the appliance will correspond to the cavity shape taken during the physical impression of the tooth subset.

[0035] Step c), such as step c2), may also include manual or automatic adjustment of the orthodontic appliance.

[0036] Each appliance prepared according to the treatment plan covers only a subset of teeth, not all teeth.

[0037] In an alternative implementation, step a) includes collecting digital representations of more teeth than the comparative subset of teeth.

[0038] For example, teeth adjacent to a subset of teeth may also be included in the digital representation, and / or teeth on another jawbone may also be included. Teeth on another jawbone may be important for determining occlusion. Including more teeth in the digital representation can improve treatment planning, for example, by providing more data for simulating the movement of teeth from the initial arrangement to the final arrangement.

[0039] In an alternative implementation, step c1) includes preparing a mold associated with more teeth than a subset of teeth.

[0040] For example, a mold or model may include opposing teeth, which can help provide a better bite. For instance, if correction of the lower (mandibular) four incisors is required, the upper jaw may be scanned / imaged to ensure, during digital planning, that the target position of the lower incisors to be corrected is functionally and aesthetically properly aligned with the upper incisors. Furthermore, the mold may include one or more additional teeth at each end of a subset of teeth.

[0041] In an alternative implementation, the tooth subset may include the first six, eight, or ten teeth.

[0042] If the target tooth is an incisor, then that number of teeth in the tooth subset can be used. For example, if the target tooth is two incisors, the tooth subset can contain six teeth. If the target tooth is three or four incisors, the tooth subset can use eight or ten teeth.

[0043] In an alternative implementation, the tooth subset includes one, some, or all of the molars in the jawbone branches.

[0044] If only the back teeth need to be moved, and the appliance only covers the molars and premolars, the appliance will be barely visible and will likely have little impact on speech. This can encourage patients to wear the appliance for longer periods.

[0045] The extent of teeth covered by a partial orthodontic appliance (a subset of teeth) can vary not only depending on the teeth requiring correction in the overall treatment plan, but also in stages. For example, this invention can be applied to initial treatment, using a posterior partial orthodontic appliance (the last four teeth) to move (e.g., distalize) the molars, followed by the use of a partial orthodontic appliance covering the first eight teeth to correct the canines and incisors in later stages of treatment. Therefore, even if the treatment extends to the correction of both front and back teeth, partial orthodontic appliances can be used at different stages of treatment.

[0046] In an alternative implementation, the digital representation includes a notch for mechanical engagement with an attachment that can be attached to one tooth in a subset of teeth.

[0047] The attachment can be permanently attached to one or more teeth in a subset of teeth, particularly non-target teeth. Adhesives can be used to secure the attachment to the teeth. The attachment can be of any shape and protrude from the tooth to which it is attached. Common attachments can be used.

[0048] In digital representation, indentations can be provided by imaging a subset of teeth that already contain attachments. The shape of the indentation can be matched to the shape of the attachment.

[0049] If a partial brace for the anterior teeth includes the first premolars, it usually has sufficient gripping / retention force to hold the teeth in place. A partial brace that only includes the four back molars can also have sufficient retention force because the undercuts on these teeth are more pronounced. However, because the number of teeth covered by a partial brace is limited, the brace can more easily fall off / detach from the subset of teeth, especially when only the anterior teeth are involved (because the undercut profile of the anterior teeth is less pronounced than that of the molars, thus the gripping / retention force on the brace may be less).

[0050] To address this issue, attachments and indentations are provided. By placing the attachment on the tooth—perhaps a premolar or canine—a clear aligner, fabricated with a properly matched indentation, can then engage with the attachment, providing an additional retention mechanism. In other words, a releasable mechanical interlock is formed between the indentation and the attachment, thus providing additional retention force for the aligner on a subset of teeth.

[0051] In an alternative implementation, step b) includes repositioning and / or reorienting the indentation relative to the attachment.

[0052] Therefore, the position and / or orientation of the indentation and attachment do not perfectly match. This slight mismatch can result in lateral and / or rotational deviations. Therefore, a slight difference can be intentionally introduced between the attachment position and / or orientation and the matching attachment indentation in the appliance to further ensure good fit, for example, on the anterior teeth. In one implementation, assuming a rectangular attachment on the lateral (buccal) surface of the canine, rotation of the attachment groove / indentation on the appliance relative to the attachment position (e.g., counterclockwise rotation on the upper right and lower left arches, or clockwise rotation on the upper left and lower right arches) can generate a positive torque and cause the appliance to rotate on the anterior teeth (incisors), thereby ensuring a “tight” attachment. In other words, this difference is intentionally created to enhance the attachment of the appliance to a subset of teeth, in contrast to known techniques where attachments and indentations are designed to achieve desired tooth movements, such as rotation / twist of the canines, that are difficult to achieve without proper gripping force.

[0053] In an alternative implementation, step b) includes at least locally reducing the digital representation of the teeth with undercuts (from the direction in which the appliance is placed on the subset of teeth).

[0054] This implementation corresponds to setting the contours of the aligner so that it can fit snugly against / clamp the undercuts of the teeth. In fact, the digital dental arch and tooth model (digital representation) upon which the 3D printing used to manufacture the aligner can be digitally modified / adjusted. During adjustment, instead of simply replicating the teeth and gums in the target posture precisely at each intermediate and / or final alignment, the corresponding digital representation can be adapted so that, in cases where the tooth contour is narrow, the undercut contours are designed to be slightly narrower below the undercuts when viewed from the direction the aligner is placed on a subset of teeth. The effect of this is likely to be a tighter fit and better retention. A major advantage of this improved retention is that it may eliminate the need for attachments to the teeth, thus avoiding the clinical step of visiting a dentist or orthodontist in person.

[0055] Reduction in the numerical representation of teeth can be achieved by decreasing the tooth circumference, enhancing undercuts, and / or locally reducing or recessing the numerical representation of teeth. This improvement in retention is most effective on teeth that already have undercuts, such as molars or premolars. Furthermore, this can be applied to multiple teeth, especially non-target teeth.

[0056] The reduction in dental numerical representation can be applied to undercuts. In other words, in the macrodental numerical representation, existing undercuts can be added, or artificial undercuts can be created.

[0057] In an alternative implementation, step c2) includes at least locally increasing the thickness of the orthodontic material compared to standard orthodontic material.

[0058] The orthodontic appliance material can be a thin film or disc made of plastic material that is rigid at room temperature or body temperature but becomes soft when heated.

[0059] Typically, orthodontic appliance materials have a standard thickness suitable for most applications. To enhance the application of force or torque, the thickness of the appliance material can be increased locally, such as in areas where more force or torque needs to be transmitted. Alternatively, the overall thickness of the appliance material can be increased compared to the standard thickness. The thickness can be between 0.5 mm and 1 mm. Both approaches result in better application of force / torque to the target teeth.

[0060] Because partial orthodontic appliances are fixed to fewer teeth than conventional orthodontic appliances, the force or torque applied to the target teeth may be less in certain cases. This may prevent the desired movement (target rotation and translation) from being achieved during treatment using partial orthodontic appliances.

[0061] According to simulations conducted by the inventors, this effect is not significant in most cases, reaching approximately 75% of the effect of a full orthodontic appliance in the worst case, and over 90% in most cases (it should be noted that even a full orthodontic appliance cannot achieve complete target rotation and translation). Furthermore, the localized increase in thickness offsets the potential loss of force or torque.

[0062] In an alternative implementation, step b) includes preparing a virtual final arrangement. The virtual final arrangement may include the pose of one or more target teeth that has been moved from the pose of the one or more target teeth in the initial arrangement to a pose outside the pose of the one or more target teeth in the final arrangement.

[0063] This means that the virtual final alignment involves the target tooth's pose being moved outside the corresponding pose in the final alignment. In other words, if the target tooth is moved according to the virtual final alignment, the target tooth will move a greater amount of time relative to the final alignment. For example, if the final alignment involves the tooth rotating 5° relative to the initial alignment's pose, the virtual final alignment might involve the tooth rotating 7°. This example also applies to lateral movements, tilts, and / or lateral tilts.

[0064] When performing a virtual final alignment, it is considered that the orthodontic appliances will not completely change the posture according to the virtual final alignment, but only to a certain extent, such as changing by 90°. Therefore, taking into account the difference between the posture of the virtual final alignment and the actual posture, the target teeth will eventually achieve the posture of the final alignment.

[0065] The virtual final permutation can be calculated based on simulations similar to those used to prepare intermediate and / or final permutations.

[0066] In an alternative implementation, step b) includes distributing the difference between the poses in the virtual final arrangement and the corresponding poses in the final arrangement evenly across the respective arrangement.

[0067] Therefore, not only can the final arrangement be corrected to a virtual final arrangement, but any intermediate arrangement can also be recalculated based on the virtual final arrangement. In other words, a new treatment plan is generated based on the virtual final arrangement, where the virtual intermediate arrangements are the steps from the initial arrangement to the virtual final arrangement, as described above in conjunction with the final arrangement and intermediate arrangements respectively. Thus, each intermediate arrangement can be corrected by the same amount, such that the sum of the differences between an intermediate arrangement and its corresponding virtual intermediate arrangement equals the difference between the final arrangement and the virtual final arrangement. In the example above, if the final arrangement includes a 5° tooth rotation, then the virtual final arrangement may include a 7° tooth rotation. Then, assuming there are five intermediate arrangements, each intermediate arrangement will cause a 1° rotation, while the rotation of each virtual intermediate arrangement is 1° + (7° - 5°) / 5 = 1.2°.

[0068] Therefore, this implementation involves increasing the target rotation and / or translation for each stage (e.g., if a total rotation of 10° is required / desired to be achieved through five stages with a rotation step of 2°, then five 2.2° stages can be specified) – although this in principle would result in a final rotation of 11°. However, in practice, this overshoot can be used to compensate for any deficiencies observed when reaching the target rotation / translation.

[0069] In an optional implementation, step c) includes step c3) of directly fabricating the orthodontic appliance using additive manufacturing.

[0070] Additive manufacturing can include 3D printing. Therefore, in this embodiment, the local orthodontic appliance is fabricated based on an arrangement within the treatment plan. The local orthodontic appliance is fabricated to match the arrangement of a subset of teeth in treatment, so that the appliance fabricated in this way can be placed on the subset of teeth to move one or more target teeth. Thus, additive manufacturing utilizes digital information about the arrangement of the subset of teeth in the treatment plan. In this embodiment, since the appliance is fabricated directly, no mold is required.

[0071] Suitable 3D printing materials have been developed that allow orthodontic appliances to be printed directly on a 3D printer, eliminating the need for pre-generating molds and then vacuum-forming them. This invention may also be useful for the direct printing of orthodontic appliances, as it offers similar and / or other benefits, such as patient comfort / acceptance, in terms of increasing the number of appliances per build, correspondingly reducing printing time, and the material cost per appliance. Furthermore, the features, characteristics, and / or alternative embodiments of orthodontic appliances made using molds are also applicable to embodiments involving direct printing of orthodontic appliances. Specifically, the manufacturing apparatus is configured to directly produce orthodontic appliances, i.e., configured to 3D print appliances based on data generated in the treatment plan.

[0072] In an optional implementation, steps a) to c) are performed on the first subset of teeth, and steps a) to c) are repeated on the second subset of teeth.

[0073] The first and second tooth subsets may include one or more teeth in common. For example, the first tooth subset may include molars, while the second tooth subset may include the first six, eight, or ten teeth.

[0074] In an alternative implementation, acquiring a digital impression includes scanning a subset of teeth using an oral scanner.

[0075] An oral scanner serves as an example of an imaging device. An oral scanner is equipped with a light source, a light sensor, and / or optical components for redirecting and / or focusing the light. The oral scanner uses the light source to generate light and uses optical components (such as lenses, mirrors, etc.) to project the light onto one or more teeth and / or gums. The light reflected by the one or more teeth and / or gums is focused by the optical components onto the light sensor. The light sensor converts the information in the reflected light into a dataset. Common oral scanners can be used.

[0076] In an optional implementation, acquiring a digital impression includes: taking a physical impression of a subset of teeth, preparing a casting of the physical impression, and scanning the casting using an oral scanner.

[0077] The dental scanner may be the same as the dental scanner described above. In the art, taking a physical impression and preparing a casting based on that physical impression is well known, therefore further description is omitted.

[0078] In an alternative implementation, acquiring a digital impression includes imaging a subset of teeth using a camera.

[0079] A camera is an example of an imaging device. It can be a standard camera or a camera on a mobile device. Using a camera is sufficient to image a subset of teeth, especially when the subset refers to the front teeth. This is not possible with common orthodontic appliances because they require digital impressions of all teeth. It is generally not possible to image molars with a camera.

[0080] The processing device is configured to create a digital impression based on images and / or video captured by a camera and / or an oral scanner. This is also well known in the art.

[0081] In an alternative implementation, step b) includes simulating forces and / or torques applied to a subset of teeth, and / or including heuristic information collected in previous treatments and / or simulations.

[0082] This is done to assess the undesirable forces / torques arising from the reaction forces on the teeth used as anchorage for the target tooth movement, as well as the potential for permanent tooth movement in adjacent teeth. It is important to note that these undesirable forces are not entirely unavoidable, but it is ensured that they remain below a threshold load. If this is achieved, movement of non-target teeth within the tooth subset is likely to be relatively small (if movement occurs), thus distributing these forces across multiple non-target / adjacent teeth minimizes their impact.

[0083] Possible methods to minimize load on adjacent teeth include having the local appliance cover additional / more teeth when the calculated load on non-target teeth is too high. This can be determined heuristically from predictive load analysis of specific treatment cases, or through patient-specific analysis of load distribution across different appliance stages. As mentioned above, local appliances do not need to cover the same teeth at each stage, and therefore this can vary depending on the tooth movement required at a given stage.

[0084] Another approach to minimizing load on adjacent teeth may involve adjusting the fit of the orthodontic appliance to adjacent non-target teeth to better distribute the anchorage load. In practice, digital appliance models are further modified through heuristics or analyses tailored to the patient and treatment phase to better distribute the load across adjacent teeth.

[0085] Therefore, in an alternative implementation, step b) includes checking whether the determined force and / or torque exceeds a predetermined threshold, and if so, adding one or more teeth to the subset of teeth, and / or changing the appliance fit to distribute the load on the subset of teeth.

[0086] The predetermined threshold may be based on clinical trials and / or simulations. One or more teeth to be added to the tooth subset may be selectively adjacent to that tooth subset.

[0087] Simulations used to estimate forces and / or moments on non-target teeth may include finite element simulations. The simulations may include the following tooth movements: tilting (inclination), lateral tilting (deviation), and / or rotation. The number of target teeth in the simulation may be between 1 and 4. (S. Barone) et al. An exemplary simulation is described in “Computational Design and Engineering of Polymer Orthodontic Appliances”, published in Volume 33, Issue 8 of the International Journal of Numerical Methods for Biomedical Engineering in August 2017.

[0088] In an alternative implementation, the tooth subset includes target teeth and non-target teeth, wherein the tooth subset includes two non-target teeth on each side of each target tooth.

[0089] This configuration reliably ensures that replacing the full set of orthodontic appliances with partial appliances does not significantly reduce the force and torque applied to the target teeth.

[0090] Furthermore, the inventors have discovered that partial orthodontic appliances can typically achieve at least 80% of the directional correction effect achieved by a full set of orthodontic appliances. When multiple teeth need to move simultaneously in the same direction, although partial orthodontic appliances are not as effective as full sets of orthodontic appliances in some cases, they can still achieve at least 75% of the directional correction effect of full sets of orthodontic appliances in all cases. In fact, in most of the configurations tested by the inventors, this proportion exceeded 90%. Attached Figure Description

[0091] Examples of the invention are discussed below with reference to the accompanying drawings.

[0092] Figure 1 This is a schematic diagram of a system used to manufacture orthodontic appliances.

[0093] Figure 2 It is a flowchart depicting the steps involved in manufacturing orthodontic appliances. Detailed Implementation

[0094] Figure 1 This is a schematic diagram of a system for manufacturing orthodontic appliances. System 10 includes an imaging device 12, a processing device 14, and / or a manufacturing device 16. The imaging device 12, the processing device 14, and / or the manufacturing device 16 are electronically coupled to each other, for example, via a LAN connection or via the Internet to exchange data.

[0095] The imaging device 12 may include an oral scanner and / or a camera and is configured to scan or image a subset of teeth in a patient's jawbone. The imaging device 12 may be configured to scan or image directly in the patient's mouth or to image or scan a casting made from a physical impression of a subset of teeth.

[0096] The processing device 14 may include a computer or other processing device for executing algorithms or software. The processing device 14 may include a processor and memory, in which the algorithms or software are stored, and the processing device can create digital impressions of a subset of teeth captured by the imaging device 12. The processing device 14 may also include a display or screen for displaying the digital impressions of the subset of teeth.

[0097] The processing device 14 may also store programs, algorithms, and / or software that can be used to generate treatment plans for moving one or more target teeth within a subset of teeth. The treatment plan includes zero or one or more intermediate arrangements of the tooth subset, and a final arrangement of the tooth subset. The final arrangement includes the desired orientation of the target teeth. If intermediate arrangements exist, they include intermediate orientations between the orientation of the target teeth in the initial arrangement and the orientation of the target teeth in the final arrangement. Appliances can be fabricated for each of the intermediate arrangements and the final arrangement. Since the tooth movement achievable with a single appliance is limited, several appliances may be required to move the target teeth from the initial orientation to the final orientation; therefore, appliances associated with intermediate arrangements may be necessary.

[0098] In addition, the processing device 14 may include an input device, such as a keyboard, mouse, and / or touchscreen, for manually changing the final pose. The input device can be used to determine the final pose. Alternatively, the processing device 14 may include algorithms, software, and / or programs for determining the final arrangement based on the initial arrangement. The input device can be used to readjust the final arrangement automatically generated by the algorithm, software, and / or program.

[0099] Manufacturing apparatus 16 may include a 3D printer capable of producing molds associated with or corresponding to intermediate and / or final arrangements. Therefore, for each intermediate and final arrangement, a corresponding mold is produced using manufacturing apparatus 16. As is well known, orthodontic appliances are formed manually or automatically on the mold.

[0100] Combining Figure 2 This paper discusses a method for manufacturing orthodontic appliances.

[0101] First, a digital representation of an initial arrangement of adjacent subsets of teeth in the patient's jaw is created, for example, by scanning or imaging the subset using imaging device 12. The acquired dataset is then processed using processing device 14 to create the digital representation. For example, the subset may include the first six, eight, or ten teeth. Alternatively, the subset may include molars. Furthermore, the digital representation may not be limited to a subset of teeth and may include more teeth than a subset, or include all teeth in the patient's jaw or upper and lower jaws. More generally, the subset may include at least one, optionally two or more, non-target teeth on at least one side (optionally both sides) of the target tooth. The target tooth refers to those teeth in the subset intended to be moved by the orthodontic appliance.

[0102] Based on a digital representation of an initial arrangement of a subset of teeth, the processing device 14 can be used to formulate a treatment plan. This treatment plan may include one or more intermediate arrangements and a final arrangement as described above.

[0103] To enhance the retention of the orthodontic appliance on a subset of teeth, the numerical representation of one or more teeth within that subset can be locally narrowed below the undercut of one or more teeth. This allows for better fixation of the appliance at the undercut. This local narrowing can be done manually via an input device or automatically by software or a program.

[0104] Another method to improve the retention force of the orthodontic appliance on a subset of teeth is to attach an attachment to one or more teeth in that subset, particularly to non-target teeth. If this is done before collecting the digital representation, the digital representation already contains a notch that matches the shape of the attachment. The appliance then also incorporates this notch so that it mechanically engages or interlocks with the attachment. The position and / or orientation of the notch may be slightly varied when processing the digital representation so that the interaction between the notch and the attachment provides a biasing force, such as a biasing force that further presses the appliance against the target teeth.

[0105] Observations have shown that the movement of the target teeth does not perfectly follow the movement of the orthodontic appliances. In other words, the posture of the target teeth may not correspond to the posture in the final alignment. To address this issue, a virtual final alignment can be used instead of the final alignment, in which the posture of the target teeth is moved outside the corresponding posture in the final alignment. In this case, the difference between the posture of the target teeth in the virtual final alignment and the corresponding posture of the target teeth when the final appliances are applied makes the posture of the target teeth actually correspond to the corresponding posture in the final alignment.

[0106] Therefore, intermediate permutations can be calculated based on virtual final permutations. Specifically, the differences between the virtual final permutation and the final permutation are evenly distributed in the intermediate permutations.

[0107] Furthermore, during the preparation of the final alignment, heuristic methods can be used to simulate or determine the forces and / or torques applied to a subset of teeth. If the determined forces and / or torques exceed a corresponding threshold, more teeth are added to the final alignment so that the number of teeth covered by the appliance exceeds the subset. This allows for better distribution of forces and / or movements on the non-target teeth due to the increased availability of more teeth. Alternatively or additionally, the final alignment can be modified to better distribute forces and / or torques across the non-target teeth within the subset.

[0108] The next step is to prepare a mold associated with each intermediate and final arrangement of teeth. Alternatively, each mold can be prepared before applying the corresponding appliance, thus avoiding the need to prepare all molds simultaneously. One or more molds can be prepared using manufacturing apparatus 16.

[0109] A mold can contain more teeth than a subset of teeth. This can improve the accuracy of forming the appliance on the mold.

[0110] The final step involves forming the appliance on the corresponding mold and trimming and / or further processing as needed. This step is repeated for each mold prepared in the previous steps. The appliance is made by heating the appliance material (such as a disc or sheet) and then pressing the heated appliance material onto a subset of teeth in the mold.

[0111] The fabrication process for orthodontic appliances may include: locally increasing the thickness of the appliance material compared to standard appliances. Alternatively, a thicker appliance material than specified / recommended for full-mouth appliances may be selected. Increasing the thickness of the appliance material improves its strength, thereby generating greater force and / or torque.

[0112] The above steps can be repeated for the second subset of teeth. For example, the first subset of teeth may include molars to change their orientation, while the second subset of teeth may include the first six, eight, or ten teeth. Therefore, molars and incisors can be moved separately using two different treatment plans and two different sets of local appliances.

[0113] In another embodiment, the manufacturing apparatus 16 is configured to directly fabricate or 3D print orthodontic appliances. Therefore, in this embodiment, no mold is fabricated. Instead, information prepared in the treatment plan, such as the alignment of a subset of teeth, is used to fabricate an appliance that matches that subset of teeth. The appliance fabricated in this manner mechanically engages with the subset of teeth to provide retention force and move one or more target teeth.

Claims

1. A method for manufacturing an orthodontic appliance, the method comprising: a) Collect numerical representations of the initial arrangement of at least a subset of adjacent teeth in the patient's jawbone. b) Develop a treatment plan comprising at least one arrangement of the subset of teeth, the treatment plan being designed to move one or more target teeth in the subset of teeth from the initial arrangement to a final arrangement, and c) For the at least one arrangement, the orthodontic appliance is fabricated based on the adjacent subset of teeth, the appliance covering the subset of teeth.

2. The method of claim 1, wherein step c) comprises c1) For the at least one arrangement, prepare a mold associated with the at least adjacent subset of teeth, and c2) Form the orthodontic appliance on the mold, the appliance covering the subset of teeth.

3. The method of claim 1 or 2, wherein Step a) includes collecting digital representations of more teeth compared to the subset of teeth, and / or Step c1) includes preparing a mold associated with more teeth than the subset of teeth.

4. The method of any of the preceding claims, wherein the subset of teeth comprises the first six, eight, or ten teeth.

5. The method of any one of claims 1 to 3, wherein the subset of teeth includes molars.

6. The method as claimed in any of the preceding claims, wherein the digital representation includes an indentation for mechanical engagement with an attachment capable of being attached to one tooth of the subset of teeth.

7. The method of claim 6, wherein step b) comprises repositioning and / or reorienting the indentation relative to the attachment.

8. The method as described in any of the preceding claims, wherein step b) comprises at least partially narrowing the undercut portion represented by the tooth number to enhance grip and / or retention.

9. The method of any one of claims 2 to 8, wherein step c2) comprises increasing the thickness of the orthodontic material at least locally compared to standard orthodontic material.

10. The method of any of the preceding claims, wherein step b) comprises preparing a virtual final arrangement comprising the poses of one or more target teeth, the poses being moved outside the poses of the one or more target teeth in the final arrangement relative to the poses of the one or more target teeth in the initial arrangement.

11. The method of claim 10, wherein step b) comprises distributing the difference between the poses in the virtual final arrangement and the poses in the final arrangement evenly across the respective arrangements.

12. The method of any one of claims 1, 3 to 8, 10 and 11, wherein step c) comprises step c3) of directly fabricating the orthodontic appliance using additive manufacturing.

13. The method as claimed in any of the preceding claims, wherein steps a) to c) are performed on a first subset of teeth, and steps a) to c) are repeated on a second subset of teeth.

14. The method of any of the preceding claims, wherein collecting the digital impression comprises The subset of teeth was scanned using an oral scanner, or Take a physical impression of the subset of teeth, prepare a casting of the physical impression, and scan the casting using an oral scanner, or The subset of teeth is imaged using a camera.

15. The method as claimed in any of the preceding claims, wherein step b) comprises simulating forces and / or torques applied to the subset of teeth, and / or includes heuristic information collected in previous treatments and / or simulations.

16. The method of claim 15, wherein step b) comprises checking whether the determined force and / or torque exceeds a predetermined threshold, and if so, adding one or more teeth to the subset of teeth, and / or altering the final arrangement to distribute the load on the subset of teeth.

17. The method of any of the preceding claims, wherein the subset of teeth comprises target teeth and non-target teeth, and wherein the subset of teeth comprises at least one non-target tooth on either side of the target tooth.

18. A system for manufacturing orthodontic appliances, comprising: An imaging device for imaging at least a subset of adjacent teeth in a patient's jawbone and / or a casting of said adjacent subset of teeth in a patient's jawbone. A processing device electronically coupled to the imaging apparatus, the processing device being configured to generate a digital representation of an initial arrangement of the tooth subset and to formulate a treatment plan including at least one arrangement of the tooth subset, the treatment plan being used to move one or more target teeth in the tooth subset from the initial arrangement to a final arrangement. A manufacturing apparatus electronically coupled to the processing device, the manufacturing apparatus being configured to prepare a mold associated with the at least one adjacent subset of teeth for the at least one arrangement, and / or being configured to directly fabricate the orthodontic appliance.

Images