Support of removable components in a teeth model manufactured by means of CAM

1. A method of generating a virtual model of a set of teeth for manufacturing a physical model of the set of teeth, where the generated virtual model is configured such that at least one tooth is part of a removable component of the virtual model, the method comprising:

obtaining a virtual model of the set of teeth, the virtual model comprising a gingival part and the at least one tooth which is part of the removable component in the virtual model, the at least one tooth being removable in a longitudinal direction of the at least one tooth;

generating a cavity in said gingival part, said cavity comprising a cavity wall, into which cavity the removable component fits such that an interface between the removable component and the cavity wall is defined, where the removable component and the cavity are configured to provide a gap at said interface, the gap extending circumferentially about a portion of the removable component in a direction perpendicular to the longitudinal direction; and

providing supporting elements configured for supporting and positioning the removable component in the cavity, where the supporting elements extend in the longitudinal direction on one of said removable component and said cavity wall such that the supporting elements extend across said gap between said removable component and said cavity wall, such that in the physical model manufactured from the virtual model, the supporting elements support and position the removable component in the cavity;

wherein, in at least one cross section taken through the removable component and the gap in a direction perpendicular to the longitudinal direction, contact between the removable component and the cavity wall at said interface is provided only by surfaces of the supporting elements and the other of the removable component and the cavity wall such that, in the at least one cross section, the gap extends only between the surfaces of the supporting elements.

2. The method according to claim 1 , wherein at least part of said supporting elements are generated on the removable component such that an area of contact between the removable component and the cavity wall at said interface is controlled by a shape of adjoining surfaces of the supporting elements and the cavity wall.

3. The method according to claim 1 , wherein at least part of said supporting elements are generated on the cavity wall such that an area of contact between the removable component and the cavity wall at said interface is controlled by a shape of adjoining surfaces of the supporting elements and the removable component.

4. The method according to claim 1 , wherein the supporting elements comprise one or more friction points providing friction between the removable component and the cavity.

5. The method according to claim 1 , wherein the supporting elements are arranged in positions corresponding to each straight side of a base of the removable component.

6. The method according to claim 1 , wherein a width of said supporting element in an area of contact between the supporting elements and the other of the removable component and the cavity wall is in the range of 0.01 mm to 4 mm.

7. The method according to claim 1 , wherein a length of said supporting element in an area of contact between the supporting elements and the other of the removable component and the cavity wall is in the range of 0.01 mm to 20 mm.

8. The method according to claim 1 , wherein the height of the supporting elements is in the range of 0.05 mm to 2 mm.

9. The method according to claim 1 , wherein a number N elem of supporting elements are provided on the removable component and/or the cavity wall, where N elem is selected from the group of 3, 4, 6, 8, 9, 10, 12 or 16.

10. The method according to claim 1 , wherein a ratio between an area of contact between the supporting elements and the other of the removable component and the cavity wall and an area of said cavity wall or a ratio between the area of contact and an area of said interface is below 0.9.

11. The method according to claim 1 , wherein the supporting elements are formed as cut-off pyramids or as square frusta or rectangular frusta.

12. The method according to claim 1 , wherein the supporting elements are configured to provide that their volume overlap at least partly with a volume of the removable component or the cavity wall when the removable component is arranged in the cavity, such that a tight fit is created between the cavity and the removable component.

13. The method according to claim 1 , where a contour of the cavity wall follows an outer curve and the contour of the removable component follows an inner curve, where the inner curve is arranged inside the outer curve.

14. The method according to claim 13 , wherein supporting elements generated on said removable component comprise a surface in an area of contact between the supporting elements and the other of the removable component and the cavity wall, which surface is aligned with the outer curve, such that these supporting elements are shaped to have a surface in the area of contact which is parallel to a surface of the cavity wall at the area of contact.

15. The method according to claim 13 , wherein supporting elements are generated on the wall of said cavity and comprise a surface in an area of contact between the supporting elements and the other of the removable component and the cavity wall, which surface is aligned with the inner curve, such that these supporting elements are shaped to have a surface in the area of contact which is parallel to a surface of the removable component at the area of contact.

16. The method according to claim 1 , wherein said providing a virtual model comprises generating said virtual model from a virtual representation of the set of teeth, and wherein the virtual representation of the set of teeth is provided by scanning the set of teeth by means of an intraoral scanner or scanning an impression of the set of teeth.

17. The method according to claim 1 , wherein the method comprises digitally repositioning the gingival part of the model around the removable component, before manufacturing the physical model.

18. The method according to claim 17 , wherein digitally repositioning the gingival part of the model comprises digitally moving the gingival part of the model away from the removable component.

19. A system for generating a virtual model of a set of teeth for manufacturing a physical model of the set of teeth, where the system comprises a processor configured for:

generating a virtual model of the set of teeth, where the virtual model is based on a virtual representation of the set of teeth;

providing that at least one tooth is configured to be arranged as part of a removable component in the virtual model, where the removable component is adapted to fit into a corresponding cavity in a gingival part of the virtual model such that an interface between the removable component and a wall of the cavity is defined, where the removable component and the cavity are configured to provide a gap at said interface, the at least one tooth being removable in a longitudinal direction of the at least one tooth, and the gap extending circumferentially about a portion of the removable component in a direction perpendicular to the longitudinal direction;

providing supporting elements extending in the longitudinal direction for supporting and positioning the removable component in its corresponding cavity, where the supporting elements are provided on one of said removable component and said cavity wall such that the supporting elements extend across said gap between said removable component and said cavity wall; and

configuring the supporting elements such that, in at least one cross section taken through the removable component and the gap in a direction perpendicular to the longitudinal direction, contact between the removable component and the cavity wall at said interface is provided only by surfaces of the supporting elements and the other of the removable component and the cavity wall such that, in the at least one cross section, the gap extends only between the surfaces of the supporting elements.

20. A method of generating a virtual model of a set of teeth for manufacturing a physical model of the set of teeth, where at least one tooth of the manufactured physical model is part of a removable component which is removable in a longitudinal direction of the at least one tooth, the method comprising:

obtaining a virtual model of the set of teeth, the virtual model of the set of teeth comprising a gingival part and the at least one tooth;

generating a virtual model of the removable component comprising the at least one tooth;

generating in said gingival part a cavity comprising a cavity wall, into which cavity the virtual model of the removable component fits with a gap such that an interface between the removable component and the cavity wall is defined, the gap extending circumferentially about a portion of the virtual model of the removable component in a direction perpendicular to the longitudinal direction; and

providing virtual supporting elements to the cavity wall, the virtual supporting elements extending in the longitudinal direction,

where the supporting elements in the manufactured physical model support and position the removable component in the cavity, and in at least one cross section taken through the removable component and the gap in a direction perpendicular to the longitudinal direction, contact between the removable component and the cavity wall at said interface is provided only by surfaces of the supporting elements and the removable component such that, in the at least one cross section, the gap extends only between the surfaces of the supporting elements.

21. A method of generating a virtual model of a set of teeth for manufacturing a physical model of the set of teeth, where at least one tooth of the manufactured physical model is part of a removable component which is removable in a longitudinal direction of the at least one tooth, the method comprising:

obtaining a virtual model of the set of teeth, the virtual model of the set of teeth comprising a gingival part and the at least one tooth;

generating a virtual model of the removable component comprising the at least one tooth;

generating in said gingival part a cavity comprising a cavity wall, into which cavity the virtual model of the removable component fits with a gap such that an interface between the removable component and the cavity wall is defined, the gap extending circumferentially about a portion of the virtual model of the removable component in a direction perpendicular to the longitudinal direction; and

providing virtual supporting elements to the portion of the removal component at the interface, the virtual supporting elements extending in the longitudinal direction,

where the supporting elements in the manufactured physical model support and position the removable component in the cavity, and in at least one cross section taken through the removable component and the gap in a direction perpendicular to the longitudinal direction, contact between the removable component and the cavity wall at said interface is provided only by surfaces of the supporting elements and the cavity wall such that, in the at least one cross section, the gap extends only between the surfaces of the supporting elements.

22. A method of generating a virtual model of a set of teeth for manufacturing a physical model of the set of teeth, where at least one tooth of the manufactured physical model is part of a removable component which is removable in a longitudinal direction of the at least one tooth, the method comprising executing computer program code on a data processing system, where the computer program code when executed causes the data processing system to:

obtain a virtual model of the set of teeth;

generate a virtual model of the removable component from the virtual model of the set of teeth, where the virtual model of the removable component comprises the at least one tooth;

generate a cavity in the virtual model of the set of teeth, the cavity comprising a cavity wall;

where the virtual model of the removable component fits into the cavity with a gap between the removable component and the cavity wall, the gap extending circumferentially about a portion of the virtual model of the removable component in a direction perpendicular to the longitudinal direction; and

generating one or more supporting elements on the virtual model of the removable component and/or on the cavity wall, said supporting elements extending across the gap such that contact between the removable component and the cavity wall at said interface is provided only by the supporting elements such that, in the at least one cross section, the gap extends only between the supporting elements.