Multilayer dental appliances and related methods and systems
A dental appliance for positioning a patient's teeth includes a removable orthodontic tooth positioning appliance having teeth receiving cavities shaped to directly receive at least some of the patient's teeth and apply a resilient positioning force to the patient's teeth. The appliance includes a hard polymer layer having a hard polymer layer elastic modulus disposed between a first soft polymer layer having a first soft polymer layer elastic modulus and a second soft polymer layer having a second soft polymer layer elastic modulus. The hard polymer layer elastic modulus is greater than each of the first soft polymer layer elastic modulus and the second soft polymer layer elastic modulus. At least one of the first soft polymer layer and the second soft polymer layer has a flexural modulus of greater than about 35,000 psi.
1. A dental appliance for positioning a patient's teeth from a first arrangement toward a second arrangement, the dental appliance comprising:
a plurality of tooth-receiving cavities shaped to receive and resiliently reposition the patient's teeth from the first arrangement toward the second arrangement;
three or more polymer layers, the three or more polymer layers comprising:
a hard polymer layer comprising a co-polyester and having a flexural modulus greater than about 150,000 psi; and
a soft polymer layer comprising a thermoplastic polyurethane elastomer and having an elongation at break of greater than about 200%, and a hardness from about 60 A to about 85 D.
2. The dental appliance of claim 1 , wherein the soft polymer layer has an ultimate tensile strength of greater than about 5000 psi.
3. The dental appliance of claim 1 , wherein the hard polymer layer has an ultimate tensile strength of greater than 150,000 psi.
4. The dental appliance of claim 1 , wherein the hard polymer layer has a tensile modulus greater than 150,000 psi.
5. The dental appliance of claim 1 , wherein the soft polymer layer has a flexural modulus of greater than about 35,000 psi.
6. The dental appliance of claim 1 , wherein the hard polymer layer has a tensile strength at yield between 4000 psi and 6500 psi.
7. The dental appliance of claim 1 , wherein the hard polymer layer has an elongation at break of greater than about 70%.
8. The dental appliance of claim 1 , wherein the hard polymer layer has a hard polymer layer elastic modulus and the soft polymer layer has a soft polymer layer elastic modulus less than the hard polymer layer elastic modulus.
9. The dental appliance of claim 1 , wherein the soft polymer layer has a compression set greater than 40% after 24 hours at 70° C.
10. The dental appliance of claim 1 , wherein the dental appliance has a thickness of between 500 μm and 1200 μm.
11. A plurality of dental appliances for positioning a patient's teeth, having a plurality of tooth-receiving cavities shaped to directly receive at least some of the patient's teeth and apply a resilient positioning force to the patient's teeth, wherein the plurality of dental appliances are shaped to move teeth from one arrangement to a successive arrangement, and wherein at least at one of the plurality of dental appliances comprises:
three or more polymer layers, the three or more polymer layers comprising:
a hard polymer layer comprising a co-polyester and having a flexural modulus greater than about 150,000 psi; and
a soft polymer layer comprising a thermoplastic polyurethane elastomer and having an elongation at break of greater than about 200%, and a hardness from about 60 A to about 85 D.
12. The plurality of dental appliances of claim 11 , wherein the soft polymer layer has an ultimate tensile strength of greater than about 5000 psi.
13. The plurality of dental appliances of claim 11 , wherein the hard polymer layer has an ultimate tensile strength of greater than 150,000 psi.
14. The plurality of dental appliances of claim 11 , wherein the hard polymer layer has a tensile modulus greater than 150,000 psi.
15. The plurality of dental appliances of claim 11 , wherein the soft polymer layer has a flexural modulus of greater than about 35,000 psi.
16. The plurality of dental appliances of claim 11 , wherein the hard polymer layer has a tensile strength at yield between 4000 psi and 6500 psi.
17. The plurality of dental appliances of claim 11 , wherein the hard polymer layer has an elongation at break of greater than about 70%.
18. The plurality of dental appliances of claim 11 , wherein the hard polymer layer has a hard polymer layer elastic modulus and the soft polymer layer has a soft polymer layer elastic modulus less than the hard polymer layer elastic modulus.
19. The plurality of dental appliances of claim 11 , wherein the soft polymer layer has a compression set greater than 40% after 24 hours at 70° C.
20. The plurality of dental appliances of claim 11 , wherein at least one of the dental appliances has a thickness of between 500 μm and 1200 μm.
21. A plurality of dental appliances for positioning a patient's teeth, the plurality of dental appliances comprising:
a first dental appliance comprising:
a first plurality of tooth-receiving cavities shaped to receive and resiliently reposition the patient's teeth from a first arrangement toward a second arrangement;
first three or more polymer layers, the first three or more polymer layers comprising:
a first hard polymer layer comprising a co-polyester and having a flexural modulus greater than about 150,000 psi; and
a first soft polymer layer comprising a thermoplastic polyurethane elastomer and having an elongation at break of greater than about 200%, and a hardness from about 60 A to about 85 D; and
a second dental appliance comprising:
a second plurality of tooth-receiving cavities shaped to receive and resiliently reposition the patient's teeth from the second arrangement toward a third arrangement;
second three or more polymer layers, the second three or more polymer layers comprising:
a second hard polymer layer comprising a co-polyester and having a flexural modulus greater than about 150,000 psi; and
a second soft polymer layer comprising a thermoplastic polyurethane elastomer and having an elongation at break of greater than about 200%, and a hardness from about 60 A to about 85 D.
22. The plurality of dental appliances of claim 21 , wherein the first soft polymer layer and the second soft polymer layer has an ultimate tensile strength of greater than about 5000 psi.
23. The plurality of dental appliances of claim 21 , wherein the first hard polymer layer and the second hard polymer layer has an ultimate tensile strength of greater than 150,000 psi.
24. The plurality of dental appliances of claim 21 , wherein the first hard polymer layer and the second hard polymer layer has a tensile modulus greater than 150,000 psi.
25. The plurality of dental appliances of claim 21 , wherein the first soft polymer layer and the second soft polymer layer has a flexural modulus of greater than about 35,000 psi.
26. The plurality of dental appliances of claim 21 , wherein the first hard polymer layer and the second hard polymer layer has a tensile strength at yield between 4000 psi and 6500 psi.
27. The plurality of dental appliances of claim 21 , wherein the first hard polymer layer and the second hard polymer layer has an elongation at break of greater than about 70%.
28. The plurality of dental appliances of claim 21 , wherein:
the first hard polymer layer and the second hard polymer layer has a hard polymer layer elastic modulus; and
the first soft polymer layer and the second soft polymer layer has a soft polymer layer elastic modulus, wherein the soft polymer layer elastic modulus is less than the hard polymer layer elastic modulus.
29. The plurality of dental appliances of claim 21 , wherein the first soft polymer layer and the second soft polymer layer has a compression set greater than 40% after 24 hours at 70° C.
30. The plurality of dental appliances of claim 21 , wherein at least one of the first dental appliance or second dental appliance dental appliance has a thickness of between 500 μm and 1200 μm.