There are several different types of palate expanders, including some that are removable. However, they are often secured in the mouth until the treatment is complete.
Removable
A removable palate expander is a device that you can take out, like a retainer. However, even though you can take the device out, it is still meant to be worn all the time. You might remove it for eating or cleaning.
Orthodontists usually reserve these types of devices for minor situations. You turn these devices less frequently than those affixed in the mouth—every few days instead of every day.
Hyrax
This type of device is held in place by bands around the teeth. The middle of the device sits over the roof of the mouth. It contains several screws, which widen the device as you turn them. People are usually advised to turn the screws with a key-type device every day.
Quad Helix
Like the hyrax, the quad helix device (“quad” for short) attaches to the teeth with metal bands. It is a “U”-shaped metal device that uses four, helix (corkscrew-shaped) springs to achieve expansion.
You don’t have to turn a key or activate the device manually at home. Instead, an orthodontist will adjust it at periodic visits.
Haas
A Haas expander is similar to a hyrax device. However, acrylic covers the screws that sit over the roof of the mouth. An orthodontist adheres this device to the teeth with metal bands. It requires daily adjustments at home with a turn-key.