# US 2010/0167243 A1 · System and method for automatic construction of realistic looking tooth roots

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- Number: US 2010/0167243 A1
- Document ID: US20100167243A1
- Status: Published application
- Kind: A1
- Application number: 12/347,291
- Filed: 2008-12-31
- Published: 2010-07-01
- Earliest claimed: 2008-12-31
- Inventors: Anton Spiridonov; Alexander Pimenov
- Web page: https://patentgrep.com/patent/US20100167243A1

## CPC

- A61C 7/00: Orthodontics, i.e. obtaining or maintaining the desired position of teeth, e.g. by straightening, evening, regulating, separating, or by correcting malocclusions
- A61C 7/002: {Orthodontic computer assisted systems}
- 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)

## Abstract

A system and computer-implemented method including generating a patient digital tooth model including a crown component; generating landmarks on an edge of the crown component; and generating a generic digital tooth model corresponding to the patient digital tooth model. The generic digital tooth model including both root and crown components. The method also includes mapping the landmarks on the edge of the crown component on to the generic digital tooth model; solving a first morphing function to fix landmarks on an edge of the crown component to a ring-edge space; solving a second morphing function to fix landmarks on the generic digital tooth model to ring-edge space; and selecting vertices in ring-edge space to stitch tooth crown with morphed template root.

## Claims

### Claim 1

A computer-implemented method for modeling realistic looking tooth roots of a patient to facilitate dental and/or orthodontic treatment, said computer-implemented method for modeling comprising:
generating a patient digital tooth model including a crown component;
generating landmarks on an edge of said crown component;
generating a generic digital tooth model corresponding to said patient digital tooth model, said generic digital tooth model including both root and crown components;
mapping said landmarks on the edge of said crown component on to said generic digital tooth model;
solving a first morphing function to fix landmarks on edge of crown component to a ring-edge space;
solving a second morphing function to fix landmarks on said generic digital tooth model to ring-edge space; and
selecting vertexes in ring-edge space to stitch tooth crown with morphed template root.

### Claim 2 (depends on 1)

The computer-implemented method according to claim 1, wherein generating landmarks on an edge of said crown component comprises:
defining an edge of crown component using a closed curve;
dividing the closed curve into several equal parts over its length with split points;
calculating a middle point of the closed curve;
calculating a rotation vector of the middle point; and
modifying each split point into modified split points,
wherein each original and modified split point becomes a landmark of a first and second series after projecting to an edge of the crown component.

### Claim 3 (depends on 1)

The computer-implemented method according to claim 1, wherein generating landmarks on an edge of said crown component comprises determining a center of mass point for apex ends of the generic digital tooth model and determining an offset distance from the center of mass point and the apex ends.

### Claim 4 (depends on 3)

The computer-implemented method according to claim 3, wherein generating landmarks on an edge of said crown component comprises determining a predicted center of mass point for apex ends of the crown component.

### Claim 5 (depends on 4)

The computer-implemented method according to claim 4, wherein determining the predicted center of mass point comprises defining the predicted center of mass point as coordinates [0, 0, −RootLength], where RootLength is a predefined constant for each class of orthodontic tooth.

### Claim 6 (depends on 4)

The computer-implemented method according to claim 4, wherein determining the predicted center of mass point comprises defining the predicted center of mass point as coordinates [x, y, −RootLength], where RootLength is a predefined constant for each class of orthodontic tooth.

### Claim 7 (depends on 4)

The computer-implemented method according to claim 4, comprising transforming the offset distance of apex ends of the generic digital tooth model into the tooth crown coordinate system to determine a predicted location of apex ends on the crown component having the same offset distance from the predicted center of mass point.

### Claim 8

A computerized system for modeling realistic looking tooth roots of a patient to facilitate dental and/or orthodontic treatment, said computerized system comprising:
a microprocessor; and
a memory device,
said microprocessor configured to:
generate a patient digital tooth model including a crown component;
generate landmarks on an edge of said crown component;
generate a generic digital tooth model corresponding to said patient digital tooth model, said generic digital tooth model including both root and crown components;
map said landmarks on the edge of said crown component on to said generic digital tooth model;
solve a firsts morphing function to fix landmarks on edge of crown component to a ring-edge space;
solve a second morphing function to fix landmarks on said generic digital tooth model to ring-edge space; and
select vertexes in ring-edge space to stitch tooth crown with morphed template root.

### Claim 9 (depends on 8)

The system according to claim 8, wherein to generate landmarks on the edge of said crown component said microprocessor is further configured to:
define an edge of crown component using a closed curve;
divide the closed curve into several equal parts over its length with split points;
calculate a middle point of the closed curve;
calculate a rotation vector of the middle point; and
modify each split point into modified split points,
wherein each original and modified split point becomes a landmark of a first and second series after projecting to an edge of the crown component.

### Claim 10 (depends on 8)

The system according to claim 8, wherein to generate landmarks on the edge of said crown component, said microprocessor is further configured to determine a center of mass point for apex ends of the generic digital tooth model and determining an offset distance from the center of mass point and the apex ends.

### Claim 11 (depends on 10)

The system according to claim 10, wherein to generate landmarks on an edge of said crown component, said microprocessor is further configured to determine a predicted center of mass point for apex ends of the crown component.

### Claim 12 (depends on 11)

The system according to claim 11, wherein to determine the predicted center of mass point, said microprocessor is further configured to define the predicted center of mass point as coordinates [0, 0, −RootLength], where RootLength is a predefined constant for each class of orthodontic tooth.

### Claim 13 (depends on 11)

The system according to claim 11, wherein to determine the predicted center of mass point, said microprocessor is further configured to define the predicted center of mass point as coordinates [x, y, −RootLength], where RootLength is a predefined constant for each class of orthodontic tooth.

### Claim 14 (depends on 11)

The system according to claim 11, wherein said microprocessor is further configured to transform the offset distance of apex ends of the generic digital tooth model into the tooth crown coordinate system to determine a predicted location of apex ends on the crown component having the same offset distance from the predicted center of mass point.
