System and method for performing quality control

1. A system for performing quality control on manufactured dental prostheses, the system comprising:

an analysis module to best fit spatial points of a scanned 3D data model of a manufactured dental prosthesis with corresponding best-fitting spatial points of a computer-aided design (CAD) model used to manufacture the dental prosthesis, and to generate a differences model comprising a compilation of offsets between the spatial points of the scanned 3D data model and the corresponding spatial points of the CAD model; and

a quality controller to modify the differences model by trimming a bottom portion thereof near a margin line, and thereafter to determine whether the manufactured dental prosthesis is a good or a defective product based on a statistical characteristic of the modified differences model.

2. The system of claim 1 , wherein the statistical characteristic comprises a differences distribution.

3. The system of claim 1 , wherein the quality controller is further configured to trim a top portion of the differences model prior to determining the statistical characteristic of the differences model, wherein the top portion comprises an occlusal surface portion.

4. The system of claim 3 , wherein the manufactured dental prosthesis is a good part when all offsets within ±50 microns account for greater than 85% of all points in the differences model.

5. The system of claim 3 , wherein the manufactured dental prosthesis is a good part when all offsets within ±50 microns account for greater than 85% of all points in the differences model and all offsets greater than ±88 microns account for less than 1% of all points in the differences model.

6. The system of claim 3 , wherein the manufactured dental prosthesis is a defective part when all offsets greater than ±88 microns account for greater than 1% of all points in the differences model.

7. The system of claim 3 , wherein the manufactured dental prosthesis is a good part when all offsets within ±50 microns account for greater than 85% of all points in the differences model and all offsets greater than ±75 microns account for less than 1% of all points in the differences model.

8. The system of claim 3 , wherein the manufactured dental prosthesis is a good part when all offsets within ±30 microns account for greater than 85% of all points in the differences model.

9. The system of claim 3 , wherein the manufactured dental prosthesis is a good part when all offsets within ±70 microns account for greater than 85% of all points in the differences model.

10. The system of claim 1 , wherein the analysis module is further configured to:

determine a contact surface on the manufactured dental prosthesis that will be in contact with an adjacent tooth using the CAD model;

determine whether points on the contact surface are within tolerance using the differences model; and

reject the manufactured prosthesis based on a percentage of points outside of a predetermined tolerance.

11. The system of claim 1 , further comprises:

a scanner for scanning the manufactured dental prosthesis and for generating the scanned 3D data model.

12. The system of claim 10 , wherein the scanner is configured to scan the manufactured dental prosthesis with light having a wavelength between 400-500 nm.

13. The system of claim 3 , wherein the quality controller is configured to determine that the manufactured dental prosthesis is too small or large based on a distribution of differences that is negatively or positively biased.

14. The system of claim 3 , wherein the quality controller is configured to determine that the manufactured dental prosthesis has a step when a distribution of differences includes peaks at a left and right side of a normal distribution curve.

15. A method for performing quality control on manufactured dental prostheses, the method comprising:

scanning a manufactured dental prosthesis to generate a scanned 3D data model;

generating a differences model by comparing spatial points of the scanned 3D data model of the dental prosthesis with corresponding best-fitting spatial points of a computer-aided design (CAD) model used to manufacture the dental prosthesis to determine a compilation of offsets between the spatial points of the scanned 3D data model and the corresponding best-fitting spatial points of the CAD model;

trimming a bottom portion of the differences model near a margin line; and

determining whether the manufactured dental prosthesis is a good or a defective product based on a statistical characteristic of the differences model.

16. The method of claim 15 , wherein the statistical characteristic comprises a differences distribution.

17. The method of claim 16 , wherein determining whether the manufactured dental prosthesis is a good or a defective product further comprises determining the manufactured dental prosthesis is a good part when all offsets within ±50 microns account for greater than 85% of all points in the differences model.

18. The method of claim 16 , wherein determining whether the manufactured dental prosthesis is a good or a defective product further comprises determining the manufactured dental prosthesis is a good part when all offsets within ±50 microns account for greater than 85% of all points in the differences model and all offsets greater than ±88 microns account for less than 1% of all points in the differences model.

19. The method of claim 16 , wherein determining whether the manufactured dental prosthesis is a good or a defective product further comprises determining the manufactured dental prosthesis is a defective part when all offsets greater than ±88 microns account for greater than 1% of all points in the differences model.

20. The method of claim 16 , wherein determining whether the manufactured dental prosthesis is a good or a defective product further comprises determining the manufactured dental prosthesis is a good part when all offsets within ±50 microns account for greater than 85% of all points in the differences model and all offsets greater than ±75 microns account for less than 1% of all points in the differences model.

21. The method of claim 16 , wherein determining whether the manufactured dental prosthesis is a good or a defective product further comprises determining the manufactured dental prosthesis is a good part when all offsets within ±30 microns account for greater than 85% of all points in the differences model.

22. The method of claim 16 , wherein determining whether the manufactured dental prosthesis is a good or a defective product further comprises determining the manufactured dental prosthesis is a good part when all offsets within ±70 microns account for greater than 85% of all points in the differences model.

23. The method of claim 15 , further comprises:

determining a contact surface on the manufactured dental prosthesis that will be in contact with an adjacent tooth using the CAD model;

determining whether points on the contact surface of the manufactured dental prosthesis are within tolerance using the differences model; and

rejecting the manufactured prosthesis based on a percentage of points outside of a predetermined tolerance.

24. The method of claim 16 , further comprises determining that the manufactured dental prosthesis is too small or too large based on a distribution of differences that is negatively or positively biased as compared to a normal distribution.

25. The method of claim 16 , further comprises determining that the manufactured dental prosthesis has a step when a distribution of differences includes peaks at a left and right side of a normal distribution curve.

26. The method of claim 16 , further comprises trimming a top portion of the differences model prior to determining the statistical characteristic of the differences model, wherein the top portion comprises an occlusal surface portion.