Dental model superimposition using clinical indications

1. A method for displaying a superimposition of a second dental model on a first dental model of a patient's dentition, the method executed at least in part on a computer and comprising:

a) obtaining a first 3D model of the patient's dentition and obtaining a segmentation of the first 3D model to define segmented teeth;

b) obtaining a second 3D model of the patient's dentition and obtaining a segmentation of the second 3D model to identify the segmented teeth;

c) identifying at least one segmented tooth of the segmented teeth of the first and second 3D models as at least one selected tooth, wherein the at least one selected tooth is less than all teeth of the patient's dentition;

d) calculating a first model distance center-to-center of first molars along a buccolingual axis;

e) calculating a second model distance center-to-center of first molars along the buccolingual axis;

f) calculating a translation along the buccolingual axis as a movement indication;

g) determining a post-treatment target position for the at least one selected tooth of the first 3D model based at least in part on the movement indication for the at least one selected tooth;

h) registering the at least one selected tooth of the second 3D model to the at least one selected tooth of the first 3D model based on the post-treatment target position of the at least one selected tooth;

and

i) displaying an imposition of the second 3D model onto the first 3D model of the patient's dentition using registration of the at least one selected tooth.

2. The method of claim 1 wherein obtaining the first or second 3D model comprises obtaining a plurality of images from one of an intraoral scanner and a cone beam computed tomography system scan.

3. The method of claim 1 wherein registering the second 3 D model to the first 3D model comprises registering the at least one selected tooth of the second 3D model onto the post-treatment target position of the corresponding at least one selected tooth of the first 3D model.

4. The method of claim 1 wherein the movement indication comprises at least one of a translation or a rotation of the at least one selected tooth of the first 3D model.

5. The method of claim 4 wherein registering the at least one selected tooth onto the post-treatment target position comprises using one of feature matching, iterative closest points algorithm.

6. The method of claim 1 wherein the movement indication comprises at least one of a direction or a magnitude for movement of the at least one selected tooth.

7. The method of claim 1 wherein the post-treatment target position is unchanged from an initial position of the at least one selected tooth.

8. The method of claim 1 wherein the movement indication includes at least one of expansion, contraction, mesialization, and distalization.

9. The method of claim 1 wherein the segmented of the first and second 3D models include a tooth shape, a cervical limit, a label, and an axis for one or more teeth.

10. The method of claim 1 further comprising displaying a movement difference between at least one segmented tooth of the second 3D model and a corresponding segmented tooth of the first 3D model.

11. The method of claim 1 wherein the first 3D model is a mesh or point cloud.

12. The method of claim 1 further comprising generating and displaying a difference image that shows movement of the patient's dentition between the first and second 3D models.

13. The method of claim 1 , wherein calculating the translation along the buccolingual axis as the movement indication comprises:

determining a main movement direction; and

determining a movement amplitude.

14. An apparatus for displaying progress of an orthodontic treatment, the apparatus comprising:

a) a device that is configured to obtain a first 3D model of a patient's dentition and a second 3D model of the patient's dentition;

b) a processor that is configured to execute programmed instructions for:

(i) obtaining the first and second 3 D models;

(ii) segmentation of teeth in the obtained 3 D models;

(iii) identification of at least one selected tooth in the first and second 3D models wherein the at least one selected tooth is less than all of teeth of the patient's dentition;

(iv) calculation of a first model distance center-to-center of first molars along buccolingual axis;

(v) calculation of a second model distance center-to-center of first molars along the buccolingual axis;

(vi) calculation of a translation along the buccolingual axis as a movement indication;

(vii) determination of a post-treatment target position for the selected tooth of the first 3D model according to a-based at least in part on the movement indication calculated for the selected tooth, wherein the movement indication specifies a translation or rotation of the selected tooth;

(viii) registration of the at least one selected tooth of the second 3 D model to the at least one selected tooth of the first 3D model according to the determined post-treatment target position of the selected tooth;

and

c) a display in signal communication with the processor for displaying an imposition of the second 3D model onto the first 3D model of the patient's dentition based on the registration of the at least one selected tooth.

15. The apparatus of claim 14 , wherein obtaining the first or second 3D model comprises obtaining a plurality of images from one of an intraoral scanner and a cone beam computed tomography system scan.

16. The method of claim 15 , wherein determining the post-treatment target position for the at least one selected tooth of the first 3D model further comprises:

applying the translation to the first 3D model along the buccolingual axis.

17. The apparatus of claim 14 , wherein registration of the at least one selected tooth of the second 3D model to the at least one selected tooth of the first 3D model comprises registration of the at least one selected tooth of the second 3D model onto the post-treatment target position of the corresponding at least one selected tooth of the first 3D model.

18. The apparatus of claim 14 , wherein the processor is further configured to execute programmed instructions for displaying a movement difference between at least one segmented tooth of the second 3D model and a corresponding segmented tooth of the first 3D model.

19. The apparatus of claim 14 , wherein the first 3D model is a mesh or point cloud.