The present disclosure provides method, systems, and devices for expanding arch of teeth. A device for expanding an arch of teeth of a patient can include a removable shell formed of a first material having a number of cavities formed therein. The number of cavities are shaped to receive teeth of a patient. A device for expanding an arch of teeth of a patient can include an arch element extending from the removable shell in a lingual direction and across an arch width of the removable shell. The arch element can be formed of the first material and a second material that is a different material than the first material, can be designed to expand an arch of the teeth of the patient, and can have a width specific to a stage of a treatment plan.