Automated Placement of Dental Orthodontic Attachments

Abstract

An automated procedure for correcting teeth misalignment in orthodontics using the steps of Generating a 3D digital model of a jaw having the misaligned teeth. Processing the 3D model to generate a corrective plan. Designing a set of corrective elements capable of applying corrective forces to the misaligned teeth through elastic forces. Designing a set of attachments that react to the corrective forces. identifying locations for applying the attachments to the surfaces of the teeth; Bonding the attachments to the identified locations. Rescanning the jaw of the patient and generating a final 3D model of the jaw with aligned teeth. Fabricating the corrective element in accordance with geometry of the final 3D model of the jaw. Applying the corrective element to the teeth wherein. Removing the attachments. A second 3D scan can be made to determine errors, and finite element analysis may be used to determine force vectors.

Claims

1. An automated procedure for correcting teeth misalignment in orthodontics wherein the corrective forces are applied by means of a polymeric, usually transparent, tray having teeth attachments comprising: (a) generating a 3D digital model of a jaw having the misaligned teeth either by creating a mold and scanning the mold, or by digitally scanning the teeth directly; (b) processing the 3D model to generate a corrective plan for the teeth; (c) designing a set of corrective elements capable of applying corrective forces to the misaligned teeth through elastic forces, wherein the corrective elements are either brackets and arch wire or alignment trays, wherein the corrective elements can include protrusions on their mating surfaces with the attachments; (d) designing a set of attachments that react to the corrective forces, wherein the attachments include brace brackets or aligner buttons; (e) identifying locations for applying the attachments to the surfaces of the teeth; (f) bonding the attachments to the identified locations either manually or robotically; (g) fabricating the set of corrective elements, using lithographic digital printing, 3D printing or injection molding; (h) applying the corrective element to the teeth wherein: (aa) the corrective element is slightly forced to encapsulate the teeth and anchor to the attachments to generate the corrective forces through elastic forces in the use of clear aligners; or: (bb) for traditional brackets, an arch wire is affixed as a component of the corrective element with wire ties or elastic ligatures; (i) periodically replacing corrective elements with other corrective elements according to the corrective plan; (j) terminating the procedure when the last of the set of corrective elements has been applied according to the plan; (k) removing the attachments.

2. The automated procedure of claim 1 further comprising generating a mold then scanning the mold digitally.

3. The automated procedure of claim 1 further comprising digitally scanning the Jaw directly.

4. The automated procedure of claim 1 wherein the corrective elements are orthodontic brackets and arch wires.

5. The automated procedure of claim 1 wherein corrective elements are alignment trays.

6. The automated procedure of claim 1 wherein the corrective elements include protrusions on their mating surfaces with the attachments to direct the forces as designed.

7. The automated procedure of claim 1 wherein the set of attachments are brace brackets.

8. The automated procedure of claim 1 wherein the set of attachments are aligner buttons.

9. The automated procedure of claim 1 further comprising bonding the attachments to the identified locations manually.

10. The automated procedure of claim 1 further comprising bonding the attachments to the identified locations robotically.

11. An automated procedure for correcting teeth misalignment in orthodontics wherein the corrective forces are applied by means of a polymeric, usually transparent, tray having teeth attachments comprising the following steps: (a) generating a 3D digital model of a jaw having the misaligned teeth; (b) processing the 3D model to generate a corrective plan; (c) designing a set of corrective elements capable of applying corrective forces to the misaligned teeth through elastic forces; (d) designing a set of attachments that react to the corrective forces; (e) identifying locations for applying the attachments to the surfaces of the teeth; (f) bonding the attachments to the identified locations; (g) rescanning the jaw of the patient and generating a final 3D model of the jaw with aligned teeth; (h) fabricating the corrective element in accordance with geometry of the final 3D model of the jaw; (i) applying the corrective element to the teeth wherein: (aa) the corrective element is slightly forced to encapsulate the teeth and anchor to the attachments to generate the corrective forces through elastic forces in the use of clear aligners; (bb) for traditional brackets, affixing an arch wire as a component of the corrective element with wire ties or elastic ligatures; (j) periodically replacing the corrective element with another of the set of corrective elements according to the corrective plan; (k) terminating the procedure when the last of the set of corrective elements has been applied according to the plan; (l) removing the attachments.

12. The automated procedure of claim 11 wherein the 3D digital model is created by generating a mold then scanning the mold digitally.

13. The automated procedure of claim 11 wherein the 3D digital model is created by digitally scanning the Jaw directly.

14. The automated procedure of claim 11 wherein the corrective elements are orthodontic brackets and arch wires.

15. The automated procedure of claim 11 wherein corrective elements are alignment trays.

16. The automated procedure of claim 11 wherein the corrective elements include protrusions on their mating surfaces with the attachments to direct the forces as designed.

17. The automated procedure of claim 11 wherein the set of attachments are brace brackets.

18. The automated procedure of claim 11 wherein the set of attachments are aligner buttons.

19. The automated procedure of claim 11 further comprising bonding the attachments to the identified locations manually.

20. The automated procedure of claim 11 further comprising bonding the attachments to the identified locations robotically.

21. The automated procedure of claim 11 further comprising fabricating the corrective element using lithographic digital printing, 3D printing or injection molding.

22. A method for designing an alignment tray for correcting teeth misalignments comprising the following steps: applying a button to the teeth; scanning the teeth to generate a 3D geometric model of the surface of the misaligned teeth; using a virtual display to determine a desired final location of the teeth after alignment; using the 3D model to generate a finite element model of the teeth and supporting bone structure; using finite element modeling and parameters of bone mechanics to determine the number of correction steps to correct the misalignment successively within the tolerance of the bone structure; modifying the 3D model into a set of models each representing one of the correction steps that lead to the final teeth locations; utilizing finite element analysis to determine the force vectors necessary to cause the desired migration of the teeth for each one of the correction steps; modifying the 3D model with button attachments that interfere with the teeth to cause the force vectors; applying finite element analysis to design the trays for each of the steps with position interference between the surface of the tray, the button attachments, and the surfaces of the teeth that strains the material of the tray such that it generates the desired force vectors.

23. The method of claim 22 further comprising using finite element modeling and parameters of bone mechanics to determine a number of correction steps that correct the misalignment successively within the tolerance of the bone structure so that each step introduces interference between the surfaces of the tray and the surfaces of the teeth and buttons.

Description

DESCRIPTION OF THE FIGURES

[0047] Attention is now directed to several drawings the illustrate features of the present invention.

[0048] FIG. 1 shows a flow chart of the preferred embodiment of the present invention.

[0049] FIG. 2 shows flow chart elements of alternate embodiments.

[0050] Several figures and illustrations have been provided to aid in understanding the present invention. The scope of the present invention is not limited to what is shown in the figures.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0051] In the field of Orthodontics, misaligned teeth are corrected by the application of forces and moments over a period of time to progressively cause the teeth to migrate towards a desired location, hence correcting the misalignment. The correction is normally done by affixing mechanical protrusions to the teeth and then bridging them by a fitted retainer that applies corrective forces and moments to the teeth. For braces, the retainer is a wire that attaches to brackets adapted to receiving and retaining a pre-strained wire. For clear aligners, the retainer is a shell Tray molded from clear polymer with pockets that are fitted snuggly over Buttons to apply the desired forces and moments.

[0052] The present invention includes the design of buttons for Tray applications and the process of designing and manufacturing the Trays. The invention applies buttons of pre-designed geometry to the teeth using a robot. The design utilizes 3D modeling of teeth and applies correction algorithms to decide the form of the bracket and the geometry of correction tray that, when mounted on the buttons, applies the correct forces and moments to progressively re-align the teeth. The invention utilizes various design techniques to decide on the forces necessary to make misalignment corrections and the location and orientation of the button surfaces that react to those forces.

[0053] The procedure according to a preferred embodiment includes the following steps:

1. The teeth are scanned by a digital scanner, and a 3D digital model is generated for the jaw with misaligned teeth. Digital scanners can include the Invisalign iTero; the 3M TruDef scanner; 3Shapes Trios; and, Cerec Sirona-connect.
2. The 3D digital model is input into an orthodontic design software program to calculate the forces and moments at selected teeth locations that are necessary to make the desired teeth corrections
3. An Attachment complement is designed with reactive surfaces that can support the desired forces at the desired locations and orientations.
4. A bonding adhesive is selected with desired adhesion and bio-compatibility properties
5. The Attachments are then prepared for mounting to the target teeth by one of two methods
a. Attachments are fabricated individually to the desired shape for each tooth, or
b. Buttons are selected from a set of pre-engineered, pre-fabricated and mass-produced forms that have the desired surfaces and strength.
6. The 3D model is then input into CAD design software to design the 3D model of a set of clear aligners, if the clear aligner process is selected for the patient.
7. The 3D model is sent to a molding, or digital printing facility to fabricate the aligner trays and send the full set of aligner tray complement to the dentist/patient.
8. The Attachments are then mounted by the adhesive bonding agent to their target teeth. The adhesive may be applied at the time of mounting or pre-applied to the buttons and preserved with a protective cover; the application is done by one of two methods
a. Manually, by the Dentist, or
b. Preferably robotically, such as described in Brachium patent application published as US 2015/0057675.
c. Robotically by mounting the Buttons on a dispensing tape within an applicator carried by the robot, where the tape is dispensed to the teeth surfaces and pressed to the surface by a pressing tool, and then the adhesive is cured by a curing light suitable for the adhesive such as ultra violet light.
9. The teeth, fitted with the attachments, are then optionally re-scanned, and a new 3D digital model is generated for the teeth and the attachments
10. The second scan is used validate accuracy and to fabricate new aligners if there is an error. If there is even a slight error, and the aligner is fabricated to the original scan, this error will cause an aligner misfit.
11. The 3D model is then input into the CAD design software to design the 3D model of a set of retaining Trays
12. The 3D model is sent to a molding, or digital printing, facility to fabricate the retaining Trays and send the full Tray complement to the patient.

[0054] Parts can be fabricated out of various materials. In particular:

a. Lithographic Digital Printing.

b. 3D Printing.

[0055] c. Injection molding.

[0056] An alternative procedure is as follows for correcting teeth misalignments is as follows:

1. Applying a button to the teeth.
2. Scanning the teeth to generate a 3D geometric model of the surface of the misaligned teeth.
3. Using a virtual display to determine a desired final location of the teeth after alignment.
4. Using the 3D model to generate a finite element model of the teeth and supporting bone structure.
5. Using the finite element modeling and the parameters of the bone mechanics to determine the number of correction steps to correct the misalignment successively within the tolerance of the bone structure, where:
a. Each step introduces interference between the surfaces of the tray and the surfaces of the teeth and buttons.
b. Each step introduces the interference with a concentration at selected locations on the button as determined by the stress and strain analysis of the finite element model.
6. Modifying the 3D model into a set of models, each representing one of the correction steps that leads to the final teeth locations
7. Utilizing finite element analysis to determine the force vectors necessary to cause the desired migration of the teeth for each one of the correction steps.
8. Modifying the 3D model with button attachments that interfere with the teeth to cause the force vectors.
9. Applying finite element analysis to design the trays for each of the steps with position interference between the surface of the tray, the button attachments, and the surfaces of the teeth that strains the material of the tray such that it generates the desired force vectors.

[0057] FIG. 1 shows a flow chart of the preferred embodiment of the present invention. FIG. 2 shows flow chart elements of alternate embodiments.

Note: The accuracy of applying the brackets, or attachments, by a robot is covered by our prior applications. Basically, “a robot manipulating tools to perform a dental procedure”.

[0058] Accordingly the present invention is based on the following contrast with the prior art:

TABLE-US-00001 The prior art designs and builds Prefabricated buttons, mass produced their buttons in the tray. and ready for application to the teeth A template is used to mold and No template needed apply the buttons. Fabricate the trays based on a The present invention fabricates the scan that does not have the trays based on a scan that includes the buttons. buttons. Errors in cavity filling, Button placement is avoided, benefits squeezing and de-flashing. from robotic accuracy & consistency Dentist does manual work Automated robotically, No manual of button placement. work for dentist The buttons and the tray are The buttons are independent of the designed as a complementary tray design. set. The buttons are formed and The button are pre-fabricated at much applied at the time of the lower cost and are readily available on treatment with cost of demand. time and money added. In an embodiment of the invention the tray is formed with knob protrusions that pressure the buttons at selected locations to generate controllable force vectors.

[0059] The present invention includes stress and strain analysis software that determines the force vectors required, and adds pressure points (knobs) to the mating surface between the tray and the button that directs these forces as designed.

[0060] In summary, embodiments of the present invention include:

[0061] An automated procedure for correcting teeth misalignment in orthodontics wherein the corrective forces are applied by means of a polymeric, usually transparent, tray having teeth attachments with the steps of: [0062] (a) generating a 3D digital model of the jaw having the misaligned teeth either by creating a mold and scanning the mold, or by digitally scanning the teeth directly; [0063] (b) processing the 3D model to generate a corrective plan for the teeth; [0064] (c) designing a set of corrective elements capable of applying corrective forces to the misaligned teeth through elastic forces, wherein the corrective elements are either brackets and arch wire or alignment trays, wherein the corrective elements can include protrusions on their mating surfaces with the attachments; [0065] (d) designing a set of attachments that react to the corrective forces, wherein the attachments include brace brackets or aligner buttons; [0066] (e) identifying locations for applying the attachments to the surfaces of the teeth; [0067] (f) bonding the attachments to the identified locations either manually or robotically; [0068] (h) fabricating the set of corrective elements, using lithographic digital printing, 3D printing or injection molding; [0069] (i) applying the corrective element to the teeth wherein: [0070] (aa) the corrective element is slightly forced to encapsulate the teeth and anchor to the attachments to generate the corrective forces through elastic forces in the use of clear aligners; or: [0071] (bb) for traditional brackets, an arch wire is affixed as a component of the corrective element with wire ties or elastic ligatures; [0072] (i) periodically replacing corrective elements with other corrective elements according to the corrective plan; [0073] (j) terminating the procedure when the last of the set of corrective elements has been applied according to the plan; [0074] (k) removing the attachments.

[0075] The corrective elements can include protrusions on their mating surfaces with the attachments to direct the forces as designed. The bonding the attachments can be attached to the identified locations manually or robotically.

[0076] In an alternate embodiment, the invention can include:

[0077] An automated procedure for correcting teeth misalignment in orthodontics wherein the corrective forces are applied by means of a polymeric, usually transparent, tray having teeth attachments with the steps of: [0078] (a) generating a 3D digital model of a jaw having the misaligned teeth; [0079] (b) processing the 3D model to generate a corrective plan; [0080] (c) designing a set of corrective elements capable of applying corrective forces to the misaligned teeth through elastic forces; [0081] (d) designing a set of attachments that react to the corrective forces; [0082] (e) identifying locations for applying the attachments to the surfaces of the teeth; [0083] (f) bonding the attachments to the identified locations; [0084] (g) rescanning the jaw of the patient and generating a final 3D model of the jaw with aligned teeth; [0085] (h) fabricating the corrective element in accordance with geometry of the final 3D model of the jaw; [0086] (i) applying the corrective element to the teeth wherein: [0087] (aa) the corrective element is slightly forced to encapsulate the teeth and anchor to the attachments to generate the corrective forces through elastic forces in the use of clear aligners; [0088] (bb) for traditional brackets, affixing an arch wire as a component of the corrective element with wire ties or elastic ligatures; [0089] (j) periodically replacing the corrective element with another of the set of corrective elements according to the corrective plan; [0090] (k) terminating the procedure when the last of the set of corrective elements has been applied according to the plan; [0091] (l) removing the attachments.

[0092] The 3D digital model can be created by generating a mold then scanning the mold digitally, or where the 3D digital model is created by digitally scanning the Jaw directly. The corrective elements can include protrusions on their mating surfaces with the attachments to direct the forces as designed. The set of attachments can be brace brackets or aligner buttons. The attachments can be bonded to the identified locations manually or robotically. The corrective element can be fabricated using lithographic digital printing, 3D printing or injection molding.

[0093] Finally, according to a third embodiment, the present invention includes:

[0094] A method for designing an alignment tray for correcting teeth misalignments with the following steps: [0095] applying a button to the teeth; [0096] scanning the teeth to generate a 3D geometric model of the surface of the misaligned teeth; [0097] using a virtual display to determine a desired final location of the teeth after alignment; [0098] using the 3D model to generate a finite element model of the teeth and supporting bone structure; [0099] using finite element modeling and parameters of bone mechanics to determine the number of correction steps to correct the misalignment successively within the tolerance of the bone structure; [0100] modifying the 3D model into a set of models each representing one of the correction steps that lead to the final teeth locations; [0101] utilizing finite element analysis to determine the force vectors necessary to cause the desired migration of the teeth for each one of the correction steps;
modifying the 3D model with button attachments that interfere with the teeth to cause the force vectors; [0102] applying finite element analysis to design the trays for each of the steps with position interference between the surface of the tray, the button attachments, and the surfaces of the teeth that strains the material of the tray such that it generates the desired force vectors.

[0103] The procedure can use finite element modeling and parameters of bone mechanics to determine a number of correction steps that correct the misalignment successively within the tolerance of the bone structure so that each step introduces interference between the surfaces of the tray and the surfaces of the teeth and buttons.

[0104] Several descriptions and illustrations have been presented to aid in understanding the present invention. One with skill in the art will realize that numerous changes and variations may be made without departing from the spirit of the invention.

[0105] Each of these changes and variations is within the scope of the present invention.