Dental preparation guide

1. A method for digitally validating a previous preparation of at least one tooth in a prepared set of teeth for determining whether the prepared tooth is capable of accepting a dental restoration, said method comprising:

obtaining a virtual dental preparation guide configured for digitally validating the previous preparation of the at least one tooth, the previous preparation of the at least one tooth including the removal of tooth material from the at least one tooth;

obtaining a digital 3D representation of the prepared set of teeth, the digital 3D representation including a digital 3D representation of the previous preparation of the at least one tooth;

visualizing on a display the virtual dental preparation guide together with the digital 3D representation of the prepared set of teeth; and

validating from the visualization of the virtual dental preparation guide together with the digital 3D representation of the prepared set of teeth whether the prepared at least one tooth is shaped such that it can accept the dental restoration.

2. The method according to claim 1 , further comprising generating the virtual dental preparation guide by

virtually forming a remaining set of teeth by virtually removing said at least one tooth from the digital 3D representation of a set of teeth;

virtually providing the dental restoration expressing a target shape of the dental restoration for said at least one tooth, and virtually creating a validation surface based on the target dental restoration; and

virtually creating the dental preparation guide by combining said validation surface and at least part of the remaining set of teeth.

3. The method according to claim 2 , further comprising

manufacturing a physical dental preparation guide based on the virtually created dental preparation guide; and

validating tooth preparation based on a registration of a physical contact between the physical dental preparation guide and prepared the at least one tooth.

4. The method according to any of claim 1 , wherein the digital 3D representation of the prepared set of teeth is obtained by intra-oral scanning of the prepared teeth.

5. The method according to claim 1 , further comprising determining a distance between the digital 3D representation of the prepared set of teeth and the virtual validation surface or the virtual dental preparation guide at one or more selected locations on tooth surface.

6. The method according to claim 5 , further comprising visualizing on the display the distance at least at some of said one or more selected locations on the tooth surface.

7. The method according to claim 6 , wherein the visualizing on the display includes at least one of visualizing on the display the distances using a distance color coding, or indicating the distance using a number.

8. The method according to claim 1 , further comprising aligning the virtual dental preparation guide and the digital 3D representation of the prepared set of teeth.

9. The method according to claim 1 , further comprising visualizing on the display a virtual preparation guide surface or the virtual validation surface together with the digital 3D representation of the remaining set of teeth.

10. The method according to claim 9 , wherein the virtual preparation guide surface is created by

virtually connecting a virtual minimum preparation surface and the digital 3D representation of the remaining set of teeth; or

at least in part by a Boolean addition of the digital 3D representation of the remaining set of teeth and the virtual validation surface.

11. The method according to claim 1 , wherein the visualizing on the display includes visualizing on the display a difference map showing differences between the virtual preparation guide surface and a shape of the at least one prepared tooth in the digital 3D representation of the prepared set of teeth.

12. The method according to claim 1 , wherein the method further comprises toggling between visualizing on the display the digital 3D representation of the prepared set of teeth alone and visualizing on the display the digital 3D representation of the prepared set of teeth in combination with the virtual preparation guide surface when activated.

13. The method according to claim 1 , further comprising:

determining an insertion direction for the dental restoration,

virtually creating a validation surface based on the target dental restoration, and

determining a distance between the digital 3D representation of the prepared set of teeth and the validation surface or the virtual dental preparation guide during a virtual movement along the insertion direction into a target position of the dental preparation guide.

14. The method according to claim 1 , further comprising determining whether further preparation of the at least one tooth is required based on the digital validation of the previous preparation.

15. A nontransitory computer readable medium encoded with a program to cause a computer to execute a method for digitally validating a previous preparation of at least one tooth in a prepared set of teeth for determining whether the prepared tooth is capable of accepting a dental restoration, said method comprising:

obtaining a virtual dental preparation guide configured for digitally validating the previous preparation of the at least one tooth, the previous preparation of the at least one tooth including the removal of tooth material from the at least one tooth;

obtaining a digital 3D representation of the prepared set of teeth, the digital 3D representation including a digital 3D representation of the previous preparation of the at least one tooth;

visualizing on a display the virtual dental preparation guide together with the digital 3D representation of the prepared set of teeth; and

validating from the visualization of the virtual dental preparation guide together with the digital 3D representation of the prepared set of teeth whether the prepared at least one tooth is shaped such that it can accept the dental restoration.

16. The nontransitory computer readable medium according to claim 15 , wherein the method further comprises generating the virtual dental preparation guide by

virtually forming a remaining set of teeth by virtually removing said at least one tooth from the digital 3D representation of a set of teeth;

virtually providing the dental restoration expressing a target shape of the dental restoration for said at least one tooth, and virtually creating a validation surface based on the target dental restoration; and

virtually creating the dental preparation guide by combining said validation surface and at least part of the remaining set of teeth.

17. The nontransitory computer readable medium according to claim 15 , wherein the method further comprises determining a distance between the digital 3D representation of the prepared set of teeth and the virtual validation surface or the virtual dental preparation guide at one or more selected locations on tooth surface.

18. The nontransitory computer readable medium according to claim 17 , wherein the method further comprises visualizing on the display the distance at least at some of said one or more selected locations on the tooth surface.

19. The nontransitory computer readable medium according to claim 15 , wherein the method further comprises aligning the virtual dental preparation guide and the digital 3D representation of the prepared set of teeth.

20. The nontransitory computer readable medium according to claim 15 , wherein the method further comprises visualizing on the display a virtual preparation guide surface or the virtual validation surface together with the digital 3D representation of the remaining set of teeth.

21. The nontransitory computer readable medium according to claim 20 , wherein the virtual preparation guide surface is created by

virtually connecting a virtual minimum preparation surface and the digital 3D representation of the remaining set of teeth; or

at least in part by a Boolean addition of the digital 3D representation of the remaining set of teeth and the virtual validation surface.