Systems and methods for treatment analysis by teeth matching

• US 7,077,647 B2
• Filed: 08/22/2002
• Issued: 07/18/2006
• Est. Priority Date: 08/22/2002
• Status: Expired due to Term

• Current Assignee: Align Technology Incorporated
• Original Assignee: Align Technology Incorporated
• Inventors: Kuo, Eric, Cheng, Jihua, Choi, Woncheol
• Primary Examiner(s): Wilson, John J
• Application Number:
  US10/225,889
• Publication Number:
  US 20040038168A1
• Time in Patent Office: 1,426 Days
• Field of Search: 433/24, 433/213, 382218-219, 356/390, 356/392
• US Class Current: 433/24
• CPC Class Codes: 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
• CPC Class Codes: A61C 7/002 Orthodontic computer assisted systems

Abstract

Systems and methods are disclosed for matching computer models of two sets of teeth includes calculating a difference for two sets of teeth shapes; finding the position of one set of teeth with respect to the other set of teeth; calculating a positional difference of the corresponding teeth; and finding a corrective path to bring one set of teeth to the other set of teeth.

Claims

1. A method for determining progress of a dental treatment, the method comprising:

providing an initial digital model of a set of dental objects;

determining planned positions for the set of dental objects;

providing a subsequent digital model of the set of dental objects in their moved positions after at least some of them have been moved by the dental treatment;

individually matching each of the dental objects in the subsequent digital model with a dental object in the initial digital model to determine corresponding dental objects, the matching comprising;

identifying one or more reference points on each set of corresponding dental objects in the initial and subsequent digital models;

approximately matching each set of corresponding dental objects by approximately aligning corresponding reference points on corresponding dental objects; and

matching each set of corresponding dental objects more closely by iteratively minimizing error between corresponding reference points on corresponding dental objects;

matching the subsequent digital model as a whole with the initial digital model; and

calculating one or more positional differences between the moved and planned positions of at least some of the corresponding dental objects.

2. The method of claim 1, wherein the set of dental objects comprises a plurality of teeth in a jaw, and wherein individually matching each of the dental objects comprises:

calculating and displaying a shape difference for each tooth of the jaw; and

identifying a corresponding location for each shape difference.

3. The method of claim 1, wherein the set of dental objects comprises a plurality of teeth in a jaw, and wherein matching the subsequent and initial digital models comprises:

placing subsequent and initial digital jaw models in a single coordinate system;

selecting a positioning reference; and

determining a positional difference for each corresponding tooth in the subsequent and initial digital jaw models.

4. The method of claim 1, wherein the set of dental objects comprises a plurality of teeth in a jaw, and wherein calculating one or more positional differences comprises:

calculating one or more of intrusion, extrusion, translation, rotation, angulation, and inclination of at least one of the teeth; and

calculating rotation and orientation changes of at least one of the teeth.

5. The method of claim 1, wherein the set of dental objects comprises a plurality of teeth in a jaw, and wherein the instructions to match the subsequent and initial digital models comprise instructions to:

place subsequent and initial digital jaw models in a single coordinate system;

select a positioning reference; and

determine a positional difference for each corresponding tooth in the subsequent and initial digital jaw models.

6. The method of claim 1, wherein the set of dental objects comprises a plurality of teeth in a jaw, and wherein the instructions to calculate one or more positional differences comprise instructions to:

calculate one or more of intrusion, extrusion, translation, rotation, angulation, and inclination of at least one of the teeth; and

calculate rotation and orientation changes of at least one of the teeth.

7. The method of claim 1, wherein individually matching one of the dental objects in the subsequent digital model with a corresponding dental object in the initial digital model comprises:

identifying multiple reference points on the dental object in the subsequent model;

identifying a closest point on the dental object in the initial model that corresponds to each of the reference points on the subsequent model;

calculating a sum of the differences between each of the reference points and each of the closest points for the dental object;

calculating a rigid transform between the dental object in the subsequent model and the dental object in the initial model; and

moving the dental object in the subsequent model toward the position of the dental object in the initial model, using the rigid transform.

8. The method of claim 7, further comprising repeating the identifying, calculating and moving steps until the dental object in the subsequent model is matched to the dental object in the initial model.

9. The method of claim 1, wherein matching the subsequent and initial digital models comprises using stationary dental objects as reference dental objects.

10. The method of claim 1, wherein matching the subsequent and initial digital models comprises using dental objects moving at a low velocity as reference dental objects.

11. The method of claim 1, wherein matching the subsequent and initial digital models comprises using statistical filtering.

12. The method of claim 11, wherein using statistical filtering comprises selecting multiple dental objects having the least amount of movement between the initial and subsequent digital models as reference dental objects.

13. The method of claim 1, further comprising calculating one or more positional differences between initial positions and moved positions of corresponding dental objects.

14. A system for determining progress of a dental treatment, the system comprising:

means for providing an initial digital model of a set of dental objects;

means for determining planned positions for the set of dental objects;

means for providing a subsequent digital model of the set of dental objects after at least some of the objects have been moved by the dental treatment;

means for individually matching each of the dental objects in the subsequent digital model with a dental object in the initial digital model to determine corresponding dental objects, the matching means comprising;

means for identifying one or more reference points on each set of corresponding dental objects in the initial and subsequent digital models;

means for approximately matching each set of corresponding dental objects by approximately aligning corresponding reference points on corresponding dental objects; and

means for matching each set of corresponding dental objects more closely by iteratively minimizing error between corresponding reference points on corresponding dental objects;

means for matching the subsequent digital model as a whole with the initial digital model; and

means for calculating one or more positional differences between the moved and planned positions of at least some of the corresponding dental objects.

15. The system of claim 14, wherein the set of dental objects comprises a plurality of teeth in a jaw, and wherein the means for individually matching each of the dental objects comprises:

means for calculating and displaying a shape difference for each tooth of the jaw; and

means for identifying a corresponding location for each shape difference.

16. The system of claim 14, wherein the set of dental objects comprises a plurality of teeth in a jaw, and wherein the means for matching the subsequent and initial digital models comprises:

means for placing subsequent and initial digital jaw models in a single coordinate system;

means for selecting a positioning reference; and

means for determining a positional difference for each corresponding tooth in the subsequent and initial digital jaw models.

17. The method of claim 14, wherein the set of dental objects comprises a plurality of teeth in a jaw, and wherein calculating one or more positional differences comprises:

means for calculating one or more of intrusion, extrusion, translation, rotation, angulation, and inclination of at least one of the teeth; and

means for calculating rotation and orientation changes of at least one of the teeth.

18. A computer readable medium containing code for matching computer models of dental objects to determine progress of a dental treatment, the computer readable medium comprising instructions to:

receive an initial digital model of a set of dental objects;

determine planned positions for a the set of dental objects;

receive a subsequent digital model of the set of dental objects, wherein at least some of the dental objects have new positions in the subsequent model, relative to their positions in the initial model;

individually match each of the dental objects in the subsequent digital model with a dental object in the initial digital model to determine corresponding dental objects, including instructions to;

identify one or more reference points on each set of corresponding dental objects in the initial and subsequent digital models;

approximately match each set of corresponding dental objects by approximately aligning corresponding reference points on corresponding dental objects; and

match each set of corresponding dental objects more closely by iteratively minimizing error between corresponding reference points on corresponding dental objects;

match the subsequent digital model with the initial digital model; and

calculate one or more positional differences between the moved and planned positions of the corresponding dental objects.

19. The medium of claim 18, wherein the set of dental objects comprises a plurality of teeth in a jaw, and wherein the instructions to individually match each of the dental objects comprise instructions to:

calculate and display a shape difference for each tooth of the jaw; and

identify a corresponding location for each shape difference.

20. The medium of claim 18, wherein the dental objects comprise teeth, the medium further comprising instructions to generate one more appliances, each appliance having a geometry selected to progressively reposition the teeth from a first teeth arrangement to a second teeth arrangement.

21. The medium of claim 20, wherein the appliances move the teeth in the corrective path(s) to bring the teeth to a planned teeth position.