Orthodontic repositioning appliances having improved geometry, methods and systems
The present invention provides methods and systems including orthodontic tooth positioning appliances. An exemplary appliance can include teeth receiving cavities shaped such that, when worn by a patient, repositioning the patient's teeth from a first arrangement toward a subsequent or target arrangement. Appliances can include a cavity having one or more shaped features or protrusions shaped and/or positioned so as to apply a desired force to a patient's tooth received in the cavity and move the tooth along a desired path or direction.
1. A method comprising:
coupling an orthodontic appliance to a tooth of a patient, the orthodontic appliance comprising a first active region and a second active region, wherein the second active region mates with an attachment on the tooth;
applying a first force directly to a tooth surface from the first active region via a protrusion incorporated in the orthodontic appliance, wherein the first force includes a first translational force component directed in a first direction and a second translational force component directed in a second direction, and wherein the first translational force component and the second translational force component cause a first moment having a first magnitude and being about a center of resistance of the tooth; and
applying a countermoment to the tooth from the second active region at the attachment, a direction of the countermoment being opposed to the second direction of the second translational force component, and wherein the countermoment reduces rotation of the tooth from the first moment, the rotation resulting in part from the second translational force component, wherein the second active region is free of protrusion.
2. The method of claim 1 , further comprising reducing a tipping of the tooth due to the first moment.
3. The method of claim 1 , further comprising translating the tooth in the first direction using the first forces and the countermoment.
4. The method of claim 1 , wherein the first moment corresponds to a tipping of the tooth along a buccal-lingual orientation of the tooth.
5. The method of claim 1 , wherein:
the first active region resides at a lingual location of one of a plurality of cavities;
the second active region resides at a buccal location of the one of the plurality of cavities; and
the first direction is a buccal direction along a buccal-lingual orientation.
6. The method of claim 5 , wherein the buccal location is closer to a gingival line of the tooth than the lingual location.
7. The method of claim 1 , wherein:
the first active region resides at a buccal location of one of a plurality of cavities;
the second active region resides at a lingual location of the one of the plurality of cavities; and
the first direction is a lingual direction along a buccal-lingual orientation.
8. The method of claim 7 , wherein the lingual location is closer to a gingival line of the tooth than the buccal location.
9. The method of claim 1 , wherein a magnitude of the countermoment is equal to the first magnitude of the first moment.
10. The method of claim 1 , wherein a magnitude of the countermoment is less than the first magnitude of the first moment.
11. The method of claim 1 , wherein the protrusion comprises one or more ridges.
12. The method of claim 1 , wherein the second active region includes a sidewall portion of the orthodontic appliance that contacts the attachment.
13. A method comprising:
coupling an orthodontic appliance to a tooth of a patient, the orthodontic appliance comprising a first active region and a second active region, wherein the second active region mates with an attachment on the tooth;
translating the tooth in a first direction with a force from the first active region via a protrusion incorporated in the orthodontic appliance, wherein the force comprises a first translational force component directed in the first direction and a second translational force component directed in a second direction, wherein the first active region is in direct contract with the tooth;
applying a first moment from the first active region to the tooth, the first moment having a first magnitude and being about a center of resistance of the tooth, wherein the first moment results from the first translational force component and the second translational force component; and
controlling application of the first moment with a countermoment applied from the second active region to the tooth, the countermoment opposing the second direction of the second translational force component, the controlled application of the countermoment reducing rotation of the tooth from the first moment, the rotation resulting in part from the second translational force component, wherein the second active region is free of protrusion.
14. The method of claim 13 , further comprising managing a tipping of the tooth due to the first moment using the countermoment.
15. The method of claim 13 , wherein a magnitude of the countermoment is equal to the first magnitude of the first moment.
16. The method of claim 13 , wherein a magnitude of the countermoment is less than the first magnitude of the first moment.
17. The method of claim 13 , wherein controlling the application of the first moment with the countermoment comprises controlling a third-order root movement of the tooth.
18. The method of claim 13 , wherein the first direction comprises a buccal direction along a buccal-lingual orientation.
19. The method of claim 13 , wherein the first direction comprises a lingual direction along a buccal-lingual orientation.
20. A method comprising:
providing a first repositioning force to a tooth of a patient with one or more protrusions incorporated in an orthodontic appliance, the first repositioning force including a first translational force component having a first magnitude and directed in a first direction and a second translational force component directed in a second direction, and wherein the first translational force component and the second translational force component cause a first moment in a third direction and about a center of resistance of the tooth; and
providing a countermoment to the tooth with a ridge formed in the orthodontic appliance, the ridge having a length and a width, the length being greater than the width, the ridge configured to apply a force to the tooth to provide the countermoment, the countermoment being in a fourth direction opposed to the second direction of the second translational force component, the provided countermoment reducing rotation of the tooth from the first moment, the undesired rotation resulting in part from the second translational force component.