# US 11,992,382 B2 · Virtual fillers for virtual models of dental arches

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- Number: US 11,992,382 B2
- Document ID: US11992382B2
- Status: Granted
- Kind: B2
- Application number: 17/411,984
- Filed: 2021-08-25
- Published: 2021-12-09
- Granted: 2024-05-28
- Earliest claimed: 2017-10-05
- Assignees: Align Technology, Inc.
- Applicants: Align Technology, Inc.
- Inventors: Israel Velazquez; Andrey Cherkas; Stephan Albert Alexandre Dumothier; Anatoliy Parpara; Alexey Geraskin; Yury Slynko; Danila Chesnokov
- Web page: https://patentgrep.com/patent/US11992382B2

## CPC

- A61C 7/002: {Orthodontic computer assisted systems}
- G06T 5/70: Denoising; Smoothing
- G06T 17/20: Finite element generation, e.g. wire-frame surface description, {tesselation}
- G06T 17/205: {Re-meshing}
- G06T 19/00: Manipulating three-dimensional [3D] models or images for computer graphics
- A61C 2007/004: {Automatic construction of a set of axes for a tooth or a plurality of teeth}
- G06T 2207/30036: Dental; Teeth
- G06T 2210/36: Level of detail
- G06T 2210/41: Medical
- G06T 2210/56: Particle system, point based geometry or rendering
- G16H 50/50: for simulation or modelling of medical disorders
- A61C: DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE (non-driven toothbrushes A46B; {tongue scrapers A61B17/24;} preparations for dentistry A61K6/00; preparations for cleaning the teeth or mouth A61K8/00, A61Q11/00)
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G16H: HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA

## Abstract

A virtual filler is inserted in a virtual model of a dental site between a first tooth and a second tooth in the virtual model. One or more of the first tooth or the second tooth represent a natural tooth of a patient. Points of the first tooth, the second tooth and the virtual filler are transformed into a voxel volume. A geometry of an updated virtual filler is determined by transforming a surface of the voxel volume into a polygonal mesh.

## Claims

### Claim 1

A method for generating a virtual filler for design of an orthodontic aligner, comprising:
inserting the virtual filler in a virtual model of a dental site between a first tooth and a second tooth in the virtual model, the inserted virtual filler having a predetermined three-dimensional shape irrespective of a user manipulation, wherein one or more of the first tooth or the second tooth represent a natural tooth of a patient;
transforming a plurality of points of the first tooth, the second tooth and the virtual filler into a voxel volume; and
determining, by a processing device, a geometry of an updated virtual filler by transforming a surface of the voxel volume into a polygonal mesh.

### Claim 2 (depends on 1)

The method of claim 1, further comprising:
determining two or more adjacent teeth in the virtual model, the two or more adjacent teeth comprising the first tooth adjacent to the second tooth in the virtual model; and
selecting the plurality of points.

### Claim 3 (depends on 2)

The method of claim 2, wherein determining the two or more adjacent teeth in the virtual model comprises:
determining that the two or more adjacent teeth comprise at least three adjacent teeth in the virtual model that satisfy a crowding criterion indicative of an amount of overlap between the at least three adjacent teeth, wherein the at least three adjacent teeth comprise the first tooth, the second tooth, and a third tooth.

### Claim 4 (depends on 3)

The method of claim 3, wherein the virtual filler is a first virtual filler, the method further comprising:
inserting a second virtual filler in the virtual model between the first tooth and the third tooth; and
inserting a third virtual filler in the virtual model between the second tooth and the third tooth.

### Claim 5 (depends on 1)

The method of claim 1, wherein the plurality of points comprise first points on a surface of the first tooth, second points on a surface of the second tooth, third points on a surface of gingiva, and fourth points on the virtual filler.

### Claim 6 (depends on 5)

The method of claim 5, wherein:
selecting the first points on the surface of the first tooth comprises selecting points on the surface of the first tooth that are within a threshold distance from at least one of the virtual filler or the surface of the second tooth; and
selecting the third points on the surface of the gingiva comprises selecting points on the surface of the gingiva that are within the threshold distance of the virtual filler.

### Claim 7 (depends on 1)

The method of claim 1, further comprising:
performing a smoothing operation on the voxel volume.

### Claim 8 (depends on 7)

The method of claim 7, wherein performing the smoothing operation on the voxel volume comprises:
inflating the voxel volume by a first distance field offset to generate an inflated voxel volume;
transforming a surface of the inflated voxel volume into an inflated polygonal mesh;
transforming the inflated polygonal mesh into an intermediate voxel volume; and
deflating the intermediate voxel volume by a second distance field offset to generate a smoothed voxel volume.

### Claim 9 (depends on 8)

The method of claim 8, wherein the second distance field offset is greater than the first distance field offset.

### Claim 10 (depends on 1)

The method of claim 1, wherein the virtual filler comprises a first side and a second side, the first side of the virtual filler located within the first tooth, the second side of the virtual filler located within the second tooth.

### Claim 11 (depends on 1)

The method of claim 1, wherein the dental site comprises a dental arch, the method further comprising:
updating the virtual model to include the updated virtual filler based on the determined geometry.

### Claim 12 (depends on 11)

The method of claim 11, further comprising:
fabricating a physical mold of the dental arch using the updated virtual model, wherein the physical mold comprises material in an area of the updated virtual filler.

### Claim 13

A system for generating a virtual filler for design of an orthodontic aligner, comprising:
a memory device; and
a processing device operatively coupled to the memory device, the processing device to:
insert the virtual filler in a virtual model of a dental site between a first tooth and a second tooth in the virtual model, the inserted virtual filler having a predetermined three-dimensional shape irrespective of a user manipulation, wherein one or more of the first tooth or the second tooth represent a natural tooth of a patient;
transform a plurality of points of the first tooth, the second tooth and the virtual filler into a voxel volume; and
determine a geometry of an updated virtual filler by transforming a surface of the voxel volume into a polygonal mesh.

### Claim 14 (depends on 13)

The system of claim 13, the processing device further to:
determine two or more adjacent teeth in the virtual model, the two or more adjacent teeth comprising the first tooth adjacent to the second tooth in the virtual model; and
select the plurality of points.

### Claim 15 (depends on 13)

The system of claim 13, wherein the virtual model is a virtual model of a dental arch, the processing device further to:
update the virtual model to include the updated virtual filler based on the determined geometry.

### Claim 16 (depends on 15)

The system of claim 15, the processing device further to:
fabricate a physical mold of the dental arch using the updated virtual model, wherein the physical mold comprises material in an area of the updated virtual filler.

### Claim 17

A non-transitory computer-readable medium comprising instructions for generating a virtual filler for design of an orthodontic aligner that, responsive to execution by a processing device, cause the processing device to perform operations comprising:
inserting the virtual filler in a virtual model of a dental site between a first tooth and a second tooth in the virtual model, the inserted virtual filler having a predetermined three-dimensional shape irrespective of a user manipulation, wherein one or more of the first tooth or the second tooth represent a natural tooth of a patient;
transforming a plurality of points of the first, the second tooth and the virtual filler into a voxel volume; and
determining, by the processing device, a geometry of an updated virtual filler by transforming a surface of the voxel volume into a polygonal mesh.

### Claim 18 (depends on 17)

The non-transitory computer-readable medium of claim 17, the operations further comprising:
determining two or more adjacent teeth in the virtual model, the two or more adjacent teeth comprising the first tooth adjacent to the second tooth in the virtual model; and
selecting the plurality of points.

### Claim 19 (depends on 17)

The non-transitory computer-readable medium of claim 17, wherein the dental site comprises a dental arch, the operations further comprising:
updating the virtual model to include the updated virtual filler based on the determined geometry.

### Claim 20 (depends on 19)

The non-transitory computer-readable medium of claim 19, the operations further comprising
fabricating a physical mold of the dental arch using the updated virtual model, wherein the physical mold comprises material in an area of the updated virtual filler.