Arch expanding appliance

1. An appliance comprising:

a removable shell having a number of cavities formed therein, wherein the number of cavities are shaped to receive teeth of a patient; and

a first arch element extending from the removable shell in a lingual direction and continuing uninterrupted across the arch width of the removable shell from a first side of the removable shell to a second side of the removable shell and designed to expand an arch of the teeth of the patient, wherein the first arch element has a width specific to a stage of a treatment plan and includes at least one raised reinforcement feature that extends from the removable shell in a lingual direction and continuing uninterrupted across the arch width of the removable shell from the first side of the removable shell to the second side of the removable shell.

2. The appliance of claim 1 , wherein the first arch element is a tab element.

3. The appliance of claim 2 , wherein the tab element applies a force to a portion of the teeth of the patient.

4. The appliance of claim 3 , wherein the portion of the teeth of the patient are posterior teeth of the patient.

5. A system, comprising:

a first appliance, of a series of appliances designed to incrementally implement a treatment plan, comprising a first shell having a plurality of cavities therein designed to receive teeth of a first jaw, wherein the first appliance includes a first arch element, extending therefrom in a lingual direction and continuing uninterrupted across an arch width of the first shell from a first side of the first shell to a second side of the first shell and designed to expand an arch of the teeth of a patient, wherein the first arch element includes at least one raised feature and the first arch element has a first width specific to a first stage of the treatment plan; and

a second appliance, of the series of appliances, comprising a second shell having a plurality of cavities therein designed to receive teeth of the first jaw, wherein the second appliance includes a second arch element, wherein second arch element has a second width specific to a second stage of the treatment plan and wherein the second width is different than the first width.

6. The system of claim 5 , wherein the at least one raised feature is designed to make the first arch element more rigid.

7. The system of claim 5 , wherein the at least one raised feature is formed of the same material as the first shell.

8. The system of claim 5 , wherein the at least one raised feature is formed of the same material as the first arch.

9. The system of claim 5 , wherein the at least one raised feature is formed of a different material than the first shell and the first arch.

10. The system of claim 5 , wherein the at least one raised feature cross-sectional shape is a half circle.

11. A method of forming a dental appliance, comprising:

forming a first portion of an arch element using a virtual model of a palate of a patient and a virtual model of a number of teeth of the patient, wherein the first portion of the arch element includes at least one raised feature, is wider than an arch width of the number of teeth of a first jaw of the patient, and specific to a stage of a treatment plan;

forming a removable shell over a set of molded teeth, wherein the removable shell includes:

a number of cavities formed therein, wherein the number of cavities are shaped to receive the number of teeth of the patient; and

a second portion of the arch element extending from the first portion of the arch element and continuing uninterrupted across the arch width of the removable shell from a first side of the removable shell to a second side of the removable shell; and

connecting the first portion of the arch element to the second portion of the arch element to form the dental appliance, wherein the arch element is designed to provide a force to at least a portion of the number of teeth in a transverse direction to expand the arch of teeth of the first jaw of the patient.

12. The method of claim 11 , wherein forming the first portion of the arch element includes forming the at least one raised feature in the shape of a wave.

13. The method of claim 11 , wherein forming the first portion of the arch element includes forming the at least one raised feature in the shape of a zig-zag.

14. The method of claim 11 , wherein forming the first portion of the arch element includes forming the at least one raised feature as an elongated element that is straight in the direction of elongation.

15. The method of claim 11 , wherein forming the first portion of the arch element includes forming the at least one raised feature in a position to provide added force to the removable shell.

16. An appliance comprising:

a removable shell having a number of cavities formed therein, wherein the number of cavities are shaped to receive teeth of a patient; and

a first arch element extending from the removable shell in a lingual direction and continuing uninterrupted across the arch width of the removable shell from a first side of the removable shell to a second side of the removable shell and designed to expand an arch of the teeth of the patient, wherein the first arch element has a width specific to a stage of a treatment plan and includes at least one reinforcement feature and at least one button style feature including a top portion and a trunk portion, wherein the trunk portion is smaller than the top portion in at least one dimension.

17. The appliance of claim 16 , wherein the button style feature interlocks the first arch element with a second arch element.