CERAMIC PROCESSING AND DESIGN FOR THE DIRECT MANUFACTURE OF CUSTOMIZED LABIAL AND LINGUAL ORTHODONTIC CLEAR ALIGNER ATTACHMENTS
20190374307 ยท 2019-12-12
Assignee
Inventors
Cpc classification
B33Y10/00
PERFORMING OPERATIONS; TRANSPORTING
B33Y70/00
PERFORMING OPERATIONS; TRANSPORTING
B33Y50/00
PERFORMING OPERATIONS; TRANSPORTING
B22F1/107
PERFORMING OPERATIONS; TRANSPORTING
B22F2999/00
PERFORMING OPERATIONS; TRANSPORTING
B22F10/12
PERFORMING OPERATIONS; TRANSPORTING
B29C64/393
PERFORMING OPERATIONS; TRANSPORTING
B22F1/107
PERFORMING OPERATIONS; TRANSPORTING
B22F2998/10
PERFORMING OPERATIONS; TRANSPORTING
A61C13/0004
HUMAN NECESSITIES
B33Y80/00
PERFORMING OPERATIONS; TRANSPORTING
B33Y50/02
PERFORMING OPERATIONS; TRANSPORTING
A61C7/12
HUMAN NECESSITIES
B22F10/28
PERFORMING OPERATIONS; TRANSPORTING
C04B2235/6026
CHEMISTRY; METALLURGY
G05B19/4099
PHYSICS
B29C64/106
PERFORMING OPERATIONS; TRANSPORTING
B22F10/28
PERFORMING OPERATIONS; TRANSPORTING
Y02P90/02
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
B22F2998/10
PERFORMING OPERATIONS; TRANSPORTING
B22F10/80
PERFORMING OPERATIONS; TRANSPORTING
B22F2999/00
PERFORMING OPERATIONS; TRANSPORTING
A61C7/08
HUMAN NECESSITIES
B29L2031/7532
PERFORMING OPERATIONS; TRANSPORTING
B29K2033/08
PERFORMING OPERATIONS; TRANSPORTING
International classification
A61C7/00
HUMAN NECESSITIES
A61C7/08
HUMAN NECESSITIES
Abstract
A method of manufacturing pre-formed, customized, ceramic, labial/lingual orthodontic clear aligner attachments (CCAA) by additive manufacturing (AM) may comprise measuring dentition data of a profile of teeth of a patient, based on the dentition data, creating a three dimensional computer-assisted design (3D CAD) model of the patient's teeth using reverse engineering, and saving the 3D CAD model, designing a 3D CAD structure model for one or more CCAA on various parts of each tooth, importing data related to the 3D CAD CCAA structure model into an AM machine, directly producing the CCAA in the ceramic slurry-based AM machine by layer manufacturing, enabling the provider to deliver patient-specific CCAA's by an indirect bonding method to the patient's teeth to improve the efficacy and retention of the clear aligners.
Claims
1. A method of manufacturing pre-formed, customized, ceramic, labial/lingual orthodontic clear aligner attachments (CCAA) by additive manufacturing (AM), said method comprising: measuring dentition data of a profile of teeth of a patient; based on the dentition data, creating a three dimensional computer-assisted design (3D CAD) model of the patient's teeth using reverse engineering, and saving the 3D CAD model; designing a 3D CAD structure model for one or more CCAA on various parts of each tooth; importing data related to the 3D CAD CCAA structure model into an AM machine; directly producing the CCAA in the ceramic slurry-based AM machine by layer manufacturing, enabling the provider to deliver patient-specific CCAA's by an indirect bonding method to the patient's teeth to improve the efficacy and retention of the clear aligners.
2. The method of claim 1, wherein an adhesive material is used to hold the CCAA into the IDB tray to permit the addition of tooth-bonding resin/cement into the base of the CCAA prior to placement.
3. The method of claim 2, wherein a pre-determined volume of tooth-bonding resin/cement is applied evenly to the CCAA base before the provider receives the CCAAs.
4. The method of claim 1, wherein indirect bonding and custom CCAA placement occurs via a tray comprising a silicone based, plastic, foam, or vacuum formed tray, that carries the custom CCAA to a tooth location.
5. The method of claim 4, wherein the tray for indirect bonding/custom CCAA placement is manufactured by an additive manufacturing technique.
6. The method of claim 1, wherein a retentive shape of the CCAA is determined by the clear aligner retention based on a planned movement for a given tooth or arch.
7. The method of claim 1, wherein structural properties of the CCAA base are selectively weakened to facilitate predictable and easier debonding of the CCAA from a tooth following treatment.
8. The method of claim 7, wherein the selective weakening comprises a depression in both the base and the face surfaces of the CCAA to enable the CCAA to predictably split into two pieces, to aid in debonding.
9. The method of claim 7, wherein a face side of the CCAA has a contoured shape that prevents it from acting as a food-trap to the patient.
10. The method of claim 1, wherein a CCAA base that holds or connects the CCAA to the tooth surface is designed based on a surface profile of the tooth.
11. The method of claim 1, wherein polycrystalline ceramic CCAA's have a color that is matched to a color of a tooth to which the CCAA is to be attached, and wherein monocrystalline CCAA's are translucent.
12. The method of claim 1, wherein the CCAA has a selected color unrelated to a color of a tooth to which the CCAA is to be attached.
13. The method of claim 1, wherein the ceramic slurry-based AM machine includes a light source that is a laser or LED light source.
14. The method of claim 1, wherein a light source of the ceramic slurry-based AM machine radiates a wavelength between 400 and 500 nm.
15. The method of claim 1, wherein the ceramic slurry-based AM machine includes a digital light processing chip as light modulator.
16. The method of claim 15, wherein the digital light processing chip is a micromirror array or an LCD array.
17. The method of claim 1, wherein measuring dentition data is performed using a CBCT scanner, intra-oral scanner, a coordinate measuring machine, a structured light digitizer, or a combination thereof.
18. The method of claim 1, wherein measuring dentition data is performed by conducting 3D scanning on a casted or 3D printed teeth model.
19. The method of claim 1, wherein the light-polymerizable material is selected from the group consisting of high strength Oxide ceramics including Aluminum Oxide (Al.sub.2O.sub.3) and Zirconium Oxide (ZrO.sub.2).
20. The method of claim 1, wherein the CCAA comprises a preformed slot adapted to accept a metal wire that applies a force to move teeth.
21. The method of claim 20, wherein the pre-formed CCAA slot is at least one of rectangular, oriented in any direction, adapted to accept a ribbon arch, or circular.
22. The method of claim 21, wherein the slot accepting the wire comprises a twin design requiring ligation, or comprises a tube design not requiring ligation.
23. The method of claim 21, wherein the CAD for the CCAA with a preformed slot comprises digitally blocked out undercuts in the aligner to prevent excessive retention.
24. The method of claim 21, wherein the preformed CCAA (with or without a slot) comprises undercuts that are digitally blocked out to provide insertion and removal of the aligner on and off of the dentition.
25. The method of 24, wherein the digitally blocked out parts on the CCAA are not fixed and are strategically changed to allow for different tooth positions and desired moments of force on that tooth or overall dentition.
26. The method of claim 1, wherein the CCAA comprises opposing working edges adapted to aid in tooth angulation movement including rotational movement or other movements requiring attachments.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION OF THE INVENTION
[0026] An embodiment of the present invention provides improved techniques for creating custom lingual or labial CCAAs.
[0027] An exemplary flowchart of an embodiment a direct manufacturing process 100 of lingual or labial orthodontic CCAAs by digital light processing is shown in
[0028] In 104, based on the given dentition data, a 3D CAD model of the measured teeth is constructed based on the dentition data and saved in the computer in a typical file format, such as the .stl file format. The exterior structure of teeth is complicated, usually including irregular curves. The software may then be used to re-arrange the teeth in the model to the desired treatment outcomes that may be based on the long-axis of a tooth.
[0029] In 106, additional information, such as the desired shape and tooth location of the CCAAs are determined.
[0030] In 108, the CCAA is designed by the software or chosen from a list of options by the clinician based on the input 3D CAD model of the measured teeth, the model of the desired treatment outcomes, and the anticipated limitations of the CA and its ability to track on the teeth throughout treatment. The output of the design process may be a 3D CAD model. Such a 3D CAD model may be designed for a single lingual/labial CCAA structure, including the indirect bonding (IDB) tray.
[0031] 3D CAD CCAA structure models of labial or lingual CCAAs may be designed by computer according to the orthodontic requirements, CA material considerations, and teeth morphology.
[0032] 3D CAD CCAA structure models are processed to generate manufacturing control data for use by the production equipment. For example, where ceramic slurry-based AM equipment is used to produce the CCAAs, the software slices the 3D CAD CCAA structure models to separate it into thin layers and get the horizontal section model for each layer. Based on this section model, the ceramic slurry-based AM equipment can directly produce CCAAs, ensuring the shape of each layer is consistent to the 3D CAD structure data. For example, the thickness of such layers may be about 20 m to about 50 m (micrometers or microns) with a manufacturing accuracy of about 5 m to about 60 m by using between-layer additive error compensation.
[0033] Returning to 108 of
[0034] Digital light processing (DLP) is another 3D additive manufacturing (AM) process that works by stacking layers of a photocurable resin with an Aluminum Oxide (Al.sub.2O.sub.3) or Zirconium Oxide (ZrO.sub.2) solid loading, and followed by a thermal debinding and sintering step. The higher resolution of this process is made possible by the LED light's digital mirror device (DMD) chip and optics used. Lithography-based ceramic manufacturing (LCM) has improved this process making it more accurate with higher resolution (40 m) and rigidity. The new LCM process involves the selective curing of a photosensitive resin containing homogenously dispersed oxide or glass ceramic particles that can be fabricated at very high resolution due to imaging systems which enable the transfer of layer information by means of ever-improving LED technology.
[0035] In 110, post-processing may then be applied. For example, a thermal treatment (for binder burnout) and a sintering process may be applied to achieve optimal or improved ceramic density. For example, the debinding and sintering phase may include removing the green CCAA from the device, exposing the blank to a furnace to decompose the polymerized binder (debinding), and sintering of the ceramic material.
[0036] Examples of raw materials of the CCAAs may include powder of high strength oxides, nitrides and carbides ceramics including but not limited to: Aluminum Oxide (Al2O3), Zirconium Oxide (ZrO2), Alumina toughened Zirconia (ATZ), Zirconia-toughened alumina (ZTA), Lithiumdisilicate, Leucitesilicate, Nitrides (e.g. SiN4), and mono- or polycrystalline ceramic. The base of CCAA may be adhered to the tooth surface and the CCAA surface may be matched to matching indentations within the CA. According to requirements of mechanical properties, different composition of material may be required for the layers during the DLP manufacturing process. After being built up, the CCAAs may have a gradient and better performance.
[0037] Further, the CCAA surface may be processed based on clinical demand.
[0038] In 112, the CCAA is ready to be placed.
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[0040] Typically, the thickness 202 of the CCAA pad 204 may extend less than 2.0 mm for lingual CCAAs and less than 2.5 for labial CCAAs from the surface of the tooth, with a labial and lingual minimum extension of 0.25 mm. The CCAA pad 204 may be adhered to the tooth surface with well-known dental adhesives that may be unfilled dental resins or partially filled dental resins. Depending upon the manufacturing process used, different ceramics or composition of powder may be required for the layers. For example, if a selective laser melting manufacturing process is used, an LED light source may be used for the selective curing of a photosensitive resin containing the oxide or glass ceramic particles. Different layers may use different ceramics or compositions of powder.
[0041] The CCAA pad 204, which holds or connects the CCAA to the tooth surface, may be designed specifically according to the tooth surface profile, instead of a generalized gridding pattern. The customized CCAAs can meet individual case demand, such as increased vertical tracking for upper lateral incisors or for lower premolars to level the curve of Spee or reduce overbite. For example, as shown in
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[0043] The neutral plane of the draft may be oriented towards the tooth structure and may be flat or itself contoured to the shape of the tooth surface to which it is meant to be bonded. While any degree of retention would achieve the intended retentive interaction with bonding cement, a range of designed draft angles may be utilized to compensate for the limitations of a specific 3D printing process.
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[0048] A side view of an exemplary printed CCAA 700 is shown in
[0049] Finite-element analysis has revealed that mesial-distal forces on the sides of the attachment result in a concentration of forces in the middle third of the attachment base. The groove is defined as the area of removed material from where forces would have been most concentrated. The addition of this groove lowers the forces required to predictably create an attachment fracture down the middle vertical third of the attachment, which aids in debonding the ceramic attachment from the tooth. The weakened area, and the fracture force may be optimized by adjusting the dimensions of the fracture groove and/or the auxiliary fracture groove.
[0050] As shown in
[0051] CCAA 600 may further include an attachment such as a hook 1002, shown in
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[0055] Using the ceramic slurry-based AM technique can turn the designed model into a ceramic product rapidly. The CCAA manufacturing involves few steps and can be done on site, saving time and cost.
[0056] The described techniques may be used to manufacture CCAAs from various Oxide ceramics and light-curable materials such as Aluminum Oxide (Al.sub.2O.sub.3) and Zirconium Oxide (ZrO.sub.2).
[0057] Many patients desire a CCAA that matches the color of the tooth to which the CCAA is attached. As another example, embodiments of the present invention may provide the capability to produce translucent CCAAs, which may provide still improved appearance. Additionally, embodiments of the present invention may provide the capability to produce CCAAs in a shade closely matched to the patient's tooth shades, which may be the same shade or matched to individual teeth as the tooth shades vary.
[0058] The described techniques may be made cost-effective to the point where an individual orthodontic practice could purchase the required equipment and software.
[0059] Ceramic slurry-based AM has many advantages for orthodontic CCAA fabrication over selective laser sintering/melting (SLM) which uses thermal energy, and 3-D printing (3DP) systems that use a binder and polymer-derived ceramics (PDCs). For example, ceramic slurry-based AM may provide higher surface quality, better object resolution, and improved mechanical properties. PDCs structured using light in a stereolithographic or mask exposure process may also be used as a ceramic AM method for CCAA fabrication.
[0060] Custom lingual CCAAs may be fabricated by this method, which may receive a pre-bent customized archwire as described by US 2007/0015104 A1. Custom labial CCAAs may also receive pre-bent wires.
[0061] The procedure for the layering additive manufacturing (AM) methodology of the labial/lingual orthodontic CCAAs by ceramic slurry-based Amiss as follows.
[0062] An example of ceramic slurry-based AM is the lithography-based digital light processing (DLP) technique described in U.S. Pat. No. 8,623,264 B2, which is incorporated herein by reference, but may be briefly summarized as follows: a light-polymerizable material, the material being located in at least one trough, having a particularly light-transmissive, horizontal bottom, is polymerized by illumination on at least one horizontal platform, the platform having a pre-specified geometry and projecting into a trough, in an illumination field, wherein the platform is displaced vertically to form a subsequent layer, light-polymerizable material is then added to the most recently formed layer, and repetition of the foregoing steps leads to the layered construction of the orthodontic CCAA in the desired prescription/mold, which arises from the succession of layer geometries determined from the CAD software. The trough can be shifted horizontally to a supply position, and the supply device brings light-polymerizable material at least to an illumination field of the trough bottom, before the at least one trough is shifted to an illumination position in which the illumination field is located below the platform and above the illumination unit, and illumination is carried out, creating a green CCAA.
[0063] The light-polymerizable material or photo-reactive suspension (slurry) can be prepared based on commercially available di- and mono-functional methacrylates. An example material might be a slurry blend of 0.01-0.025 wt % of a highly reactive photoinitiator, 0.05-6 wt % a dispersant, an absorber, and 2-20 wt % of a non-reactive diluent. A solid loading of high strength Oxide ceramics such as Aluminum Oxide (Al.sub.2O.sub.3) and Zirconium Oxide (ZrO.sub.2) powder can be used, but this process may extend to other ceramic materials.
[0064] An exemplary block diagram of a computer system 700, in which the processes shown above may be implemented, is shown in
[0065] Input/output circuitry 704 provides the capability to input data to, or output data from, computer system 700. For example, input/output circuitry may include input devices, such as keyboards, mice, touchpads, trackballs, scanners, etc., output devices, such as video adapters, monitors, printers, etc., and input/output devices, such as, modems, etc. Network adapter 706 interfaces device 700 with a network 710. Network 710 may be any public or proprietary LAN or WAN, including, but not limited to the Internet.
[0066] Memory 708 stores program instructions that are executed by, and data that are used and processed by, CPU 702 to perform the functions of computer system 700. Memory 708 may include, for example, electronic memory devices, such as random-access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), electrically erasable programmable read-only memory (EEPROM), flash memory, etc., and electro-mechanical memory, such as magnetic disk drives, tape drives, optical disk drives, etc., which may use an integrated drive electronics (IDE) interface, or a variation or enhancement thereof, such as enhanced IDE (EIDE) or ultra-direct memory access (UDMA), or a small computer system interface (SCSI) based interface, or a variation or enhancement thereof, such as fast-SCSI, wide-SCSI, fast and wide-SCSI, etc., or Serial Advanced Technology Attachment (SATA), or a variation or enhancement thereof, or a fiber channel-arbitrated loop (FC-AL) interface.
[0067] The contents of memory 708 varies depending upon the function that computer system 700 is programmed to perform. In the example shown in
[0068] In the example shown in
[0069] As shown in
[0070] It is important to note that while aspects of the present invention may be implemented in the context of a fully functioning data processing system, those of ordinary skill in the art will appreciate that the processes of an embodiment of the present invention are capable of being distributed in the form of a computer program product including a computer readable medium of instructions. Examples of non-transitory computer readable media include storage media, examples of which include, but are not limited to, floppy disks, hard disk drives, CD-ROMs, DVD-ROMs, RAM, and, flash memory.
[0071] Although specific embodiments of the present invention have been described, it will be understood by those of skill in the art that there are other embodiments that are equivalent to the described embodiments. Accordingly, it is to be understood that the invention is not to be limited by the specific illustrated embodiments, but only by the scope of the appended claims.