# US 12,109,088 B2 · Method of evaluating an orthodontic appliance

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- Number: US 12,109,088 B2
- Document ID: US12109088B2
- Status: Granted
- Kind: B2
- Application number: 17/395,160
- Filed: 2021-08-05
- Published: 2021-11-25
- Granted: 2024-10-08
- Earliest claimed: 2017-06-09
- Assignees: Dental Monitoring
- Applicants: Dental Monitoring
- Inventors: Philippe Salah; Thomas Pellissard; Guillaume Ghyselinck; Laurent Debraux
- Web page: https://patentgrep.com/patent/US12109088B2

## CPC

- A61C 7/002: {Orthodontic computer assisted systems}
- A61C 9/004: {Means or methods for taking digitized impressions}
- G16H 20/40: relating to mechanical, radiation or invasive therapies, e.g. surgery, laser therapy, dialysis or acupuncture
- G16H 30/40: for processing medical images, e.g. editing
- A61C 7/08: Mouthpiece-type retainers {or positioners, e.g. for both the lower and upper arch (arch-shaped medicament applicators for teeth or gums A61C19/063; mouthguards for protecting the teeth of sportsmen A63B71/085)}
- A61C 7/10: Devices having means to apply outwardly directed force, e.g. expanders
- A61C 7/12: Brackets; Arch wires; Combinations thereof; Accessories therefor
- 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)
- G16H: HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA

## Abstract

A method for evaluating an orthodontic appliance. Acquisition of a two-dimensional “appliance image” of teeth at least partially representing the orthodontic appliance in a service position. Acquisition of a two-dimensional “dentition image” of the teeth. If a determination of comparable dental and appliance attributes is not possible from the appliance image and from the dentition image, respectively, conversion of the appliance image and/or of the dentition image so that the appliance image be compatible with the dentition image. Determination of dental and appliance attributes relative to the shape of the tooth represented on the dentition image and relative to the shape of the orthodontic appliance on the appliance image. Comparison of the dental and appliance attributes, followed by determination of at least one score. At least one image is acquired with a mobile phone.

## Claims

### Claim 1

A method for evaluating an orthodontic appliance worn by a patient, said method comprising the following steps:
1′) at an “appliance” instant, acquisition of at least one two-dimensional image of teeth of said patient, said image, referred to as “appliance image”, at least partially representing the orthodontic appliance in a service position in which it is worn by said teeth;
at a “dentition” instant, acquisition of at least one two-dimensional image of said teeth of said patient, referred to as “dentition image”;
2′) if a determination of comparable dental and appliance attributes relative to the shape of a tooth represented on the at least one dentition image and relative to the shape of the orthodontic appliance on the at least one appliance image, respectively, is not possible from said at least one appliance image and from said at least one dentition image, respectively, conversion of at least one image chosen from the at least one appliance image and the at least one dentition image so that said at least one appliance image be compatible with said at least one dentition image;
for each of a plurality of teeth represented on the at least one dentition and appliance images:
3′) determination of said dental and appliance attributes, the dental and appliance attributes at step 3′) being:
an outline of the tooth and of the orthodontic appliance on the dentition and appliance images respectively, or
a surface of the tooth and of the orthodontic appliance, respectively, determined from a plurality of dentition images and from a plurality of appliance images, respectively;
4′) comparison of the dental and appliance attributes, followed by determination of at least one score according to said comparison, said step 4′) comprising the following steps:
for each of a plurality of teeth for which the dental and appliance attributes have been determined;
i) determination of a distance between the dental and appliance attributes;
ii) determination of a distance threshold;
iii) for each of said teeth, determination of a distance score dependent on
the distance between the dental and appliance attributes, and
the distance threshold;
at least one image chosen from of said at least one appliance image and said at least one dentition image being acquired with a mobile phone by the patient or another person.

### Claim 2 (depends on 1)

The method according to claim 1, in which the appliance and dentition instants are simultaneous.

### Claim 3 (depends on 1)

The method according to claim 1, in which the appliance instant and the dentition instant are separated by a time interval greater than 4 days, 1 week and less than 6 months.

### Claim 4 (depends on 1)

The method as claimed in claim 1, comprising, after step 4′), the following step:
5) comparison of the score against an acceptability threshold and emission of information according to the result of the comparison, said information being sent to a mobile phone of the patient and/or to a dental care professional.

### Claim 5 (depends on 4)

The method as claimed in claim 4, wherein the acceptability threshold is parametrized by a dental care professional according to the patient's teeth configuration and/or the orthodontic appliance and/or the orthodontic treatment.

### Claim 6 (depends on 4)

The method according to claim 4, said information indicating
whether said orthodontic appliance has come off said tooth, and/or
whether said orthodontic appliance has changed of shape between the dental instant and the appliance instant, and/or
whether said orthodontic appliance correctly matches a surface of a tooth.

### Claim 7 (depends on 1)

The method as claimed in claim 1, in which, at steps 3′) and 4′), to check whether an orthodontic appliance has come off a tooth, or to check whether a shape of said orthodontic appliance has changed,
the appliance instant and the dentition instant are separated by a time interval greater than 4 days and less than 6 months,
the appliance attribute is an outline or a surface of said orthodontic appliance, the dental attribute is an outline or a surface of the tooth, respectively,
the score measures a difference of positions or a difference of area between the appliance attribute and the dental attribute.

### Claim 8 (depends on 1)

The method according to claim 1, wherein the orthodontic appliance is chosen among
an aligner,
a part which is rigidly fixed on a tooth and chosen among
an attachment fixed on a tooth to be interposed between said tooth and an aligner in the service position,
a button fixed on a tooth for an attachment of an elastic band,
a bracket fixed on a tooth for an attachment of a metallic wire,
a spring,
a temporary anchorage device,
a palatal expander appliance.

### Claim 9 (depends on 1)

The method according to claim 1, wherein the appliance and dentition images are extraoral photographs or extracted from an extraoral film.

### Claim 10 (depends on 1)

The method as claimed in claim 1, in which, at step 2′), said conversion is achieved if said at least one appliance image is not compatible with said at least one dentition image, an appliance image being “compatible” with a dentition image if the outlines of the teeth represented on the appliance image are superposable on the outlines of said teeth on the dentition image.

### Claim 11 (depends on 10)

The method as claimed in claim 10, in which the step 2′) comprises the following steps:
(a′) prior to step 1′), creation of a digital three-dimensional model of at least part of a dental arch bearing said teeth, or “initial reference model” and, for each tooth of the initial reference model, definition of a digital three-dimensional reference model of said tooth, or “tooth model”;
(b′) modification of the initial reference model by moving the tooth models until a final reference model compatible with the dentition image is obtained;
(c′) search for a two-dimensional view of the final reference model that is compatible with the appliance image;
(d′) conversion of the dentition image into said view.

### Claim 12 (depends on 10)

The method as claimed in claim 10, in which the step 2′) comprises the following steps:
(a′) prior to the acquisition of the at least one appliance image, creation of a digital three-dimensional model of at least part of a dental arch bearing said teeth, or “initial reference model” and, for each tooth of the initial reference model, definition of a digital three-dimensional reference model of said tooth, or “enriched tooth model”, any orthodontic appliance fixed on a tooth being part of the enriched tooth model of said tooth,
(b′) modification of the initial reference model by moving the enriched tooth models until a final reference model compatible with the appliance image is obtained;
(c′) search for a two-dimensional view of the final reference model that is compatible with the dentition image;
(d′) conversion of the appliance image into said view.

### Claim 13 (depends on 1)

The method as claimed in claim 1, in which the distances are measured in pixels.

### Claim 14 (depends on 1)

The method as claimed in claim 1, in which, in step ii), the distance threshold is dependent on the smallest of the distances determined in step i).

### Claim 15 (depends on 1)

The method as claimed in claim 1, in which, at step 3′), the dental and appliance attributes are determined, by means of at least one artificial neural network, from the at least one dentition image and from the at least one appliance image, respectively.

### Claim 16 (depends on 15)

The method as claimed in claim 15, in which the same artificial neural network(s) is/are used to determine both dental attributes and appliance attributes.

### Claim 17 (depends on 15)

The method as claimed in claim 15, in which, at step 2′), no conversion is achieved.