Orthodontic appliance having continuous shape memory

Patent metadata

Field	Value
Publication number	US-11478335-B2
Application number	US-202016907877-A
Country	US
Kind code	B2
Filing date	Jun 22, 2020
Priority date	Nov 2, 2015
Publication date	Oct 25, 2022
Grant date	Oct 25, 2022

Abstract

Continuous adjustment appliances are provided that can store a large number of geometries that can be successively accessed throughout orthodontic treatment, with each geometry can correspond to an arrangement of the patient's teeth. An appliance according to the present disclosure can be stimulated to transition among the myriad geometries, which can include changes to the overall shape of the appliance as well as the position and geometry of the cavities corresponding to a patient's teeth. Methods of creating the continuous adjustment appliances and methods of treatment using the continuous adjustment appliances are also revealed.

First claim

The invention claimed is:

1. A method for manufacturing polymeric shell dental appliances configured to conform to one or more teeth of a patient, the method comprising:
providing a first positive model of the patient's dentition, the model representing a repositioned arrangement of the patient's teeth;
forming over the model at a first molding temperature a sheet of crosslinkable, crystallizable polymeric material having a crystallization temperature range having an upper limit and a lower limit; crosslinking the polymer to create a first appliance having a first stored geometry;
providing a second model representing a first intermediate arrangement of the patient's teeth, the first intermediate arrangement including one or more teeth in different orientations than the first model;
subjecting the appliance in the first stored geometry to a second molding temperature within the crystallization temperature range and being less than the first molding temperature to create a second stored geometry in the appliance;
providing a third model representing a second intermediate arrangement of the patient's teeth, the second intermediate arrangement including one or more teeth in different orientations than the first intermediate arrangement;
subjecting the appliance in the second stored geometry to a third molding temperature within the crystallization temperature range to create a third stored geometry, the third molding temperature being less than either the first or second molding temperatures; and cooling the appliance below the lower limit of transition temperature range.

2. The method of claim 1 , wherein the crosslinkable, crystallizable polymeric material is selected from polyethylene, ethylene vinyl acetate, and combinations thereof.

3. The method of claim 1 , wherein heating the sheet comprises heating for a period of time sufficient to selectively melt at least portion of the crystalline structures in the crosslinkable, crystallizable polymeric material.

4. The method of claim 1 , wherein the crosslinkable, crystallizable polymeric material is physically crosslinkable, chemically crosslinkable, or combinations thereof.

5. The method of claim 1 and further comprising subjecting the appliance in the first stored geometry to irradiation to create a number of chemical crosslinks in the crosslinkable, crystallizable polymeric material.

6. The method of claim 5 , wherein the irradiation is selected from gamma, E-beam, and combinations thereof.

7. The method of claim 1 , and further comprising:
creating a first series of crystalline structures in the crosslinkable, crystallizable polymeric material while the shell has the second stored geometry.

8. The method of claim 1 , wherein the first mold comprises a plurality of reconfigurable tooth objects arranged relative to a physical arch, and wherein providing the second model comprises moving at least one of the tooth objects to create the second arrangement.

9. The method of claim 8 , wherein moving at least one of the tooth objects comprises moving the tooth object along a treatment path.

10. The method claim 9 , and further comprising placing the first model within a temperature controlled chamber and reducing the temperature in the chamber from the first molding temperature to the second molding temperature, and wherein the tooth model is moved along the treatment path segment while the temperature in the chamber is reduced from the first molding temperature to the second molding temperature.

11. The method of claim 1 , wherein the forming a sheet of polymeric material over at least one of the first, second, and third model includes the act of applying pressure to the respective model.

12. The method of claim 11 , wherein the forming a sheet crosslinkable polymeric material over at least one of the first, second, and third model includes the act of applying pressure to the respective model, and wherein a tooth object is moved along a treatment path segment while the pressure is applied to the respective model.

13. The method of claim 1 , wherein the crosslinkable, crystallizable polymeric material forms an increasing number of crystalline structures as the temperature is reduced from the upper limit of the crystallization temperature range to the lower limit.

14. The method of claim 1 , wherein the steps of providing the first, second, and third positive models each comprise providing a printed model of the dentition representing the desired arrangement of the patient's teeth.

15. The method of claim 1 , wherein each molding temperature is greater than 55° C.

16. The method of claim 1 , wherein crystallization temperature range is about 60° C. to about 135° C.

17. The method of claim 1 , wherein the crosslinkable, crystallizable polymeric material is a semicrystalline, non-segmented polymer.

18. A method of moving a patient's teeth of a target arrangement, the method comprising: placing an orthodontic appliance created according to the method of claim 1 on a dental arch; heating the appliance to a first transition temperature so as to modify the shape of the shell to a second configuration; placing the appliance in the second configuration on the dental arch; heating the appliance to a second transition temperature so as to the modify the shape of the shell to a third configuration; placing the appliance in the third configuration on the dental arch; the third configuration shaped to reposition the patient's teeth to the target arrangement.

19. The method of claim 18 , whererein the appliance includes crystalline structures in the polymeric material, and wherein heating the appliance to a first transition temperature disrupts a portion of the crystalline structures in the polymeric material.

20. The method of claim 18 , wherein the appliance comprises a shell that includes an inner cavity including a plurality of receptacles, and wherein heating the polymeric shell to a first transition temperature so as to modify the shape of the shell to a second configuration comprises modifying the position of at least one receptacle within the cavity.

Assignees

• 3M Innovative Properties Co

Inventors

• Lai Ming-Lai
• Rule Joseph D

Classifications

• A61C7/002

  Orthodontic computer assisted systems · CPC title

• A61C2201/007

  using shape memory effect · CPC title

• B29C2791/001

  Shaping in several steps · CPC title

• A61C7/08 Primary

  Mouthpiece-type retainers {or positioners, e.g. for both the lower and upper arch (arch-shaped medicament applicators for teeth or gums A61C19/063; mouthguards for protecting the teeth of sportsmen A63B71/085)} · CPC title

• B29C51/426

  Producing specific thermal regimes during thermoforming to obtain particular properties · CPC title