Some bite problems are easier to treat if they are caught at an early age. That’s why all children should have an orthodontic evaluation by age 7, even if it’s not yet time to begin treatment. An upper or lower jaw expander can gradually expand and open up the arch during the first phase of orthodontic treatment, especially for children and teens who are still growing.

Expander Q & A

What is an expander?

Jaw expansion with an expander helps open up the palate and widen the upper arch. An expander can also be used on the lower arch. In both cases, the expander creates more room for teeth. Usually, an expander is part of an orthodontic treatment plan for growing children and teens, since the expander can prevent bad bites and issues with misaligned teeth. Types of expander are described below.

Upper jaw expander

Upper jaw expanders (also called palatal or maxillary expanders) are fitted to you specifically. This appliance fits over several of the top teeth. The two halves of the appliance are connected at the roof of the mouth with a screw.

Patients use a specialized key to adjust the expander on a daily basis. With each turn of the key, the expander puts gentle force on the teeth, moving them apart until optimal expansion is achieved.
Upper jaw expansion is successful for growing children and teens because the upper jaw develops in two halves. But they don’t fuse together until long after puberty. An upper jaw expander promotes healthy jaw growth and development.

Lower jaw expanders

Lower jaw expanders have the same outcome — an expanded arch — but the function of them is different. Because the lower jaw bone can’t be expanded, lower expanders work by moving the teeth outward to create a more rounded arch. They can even correct teeth that are tipped inward.

Which conditions can an expander treat?

An expander is ideal for treating issues that can’t be corrected with braces alone. The doctor may recommend an expander to treat:

  • Crossbite
  • Overcrowding
  • Impacted teeth
  • Mouth breathing

How long do I wear an expander?

It depends on the severity of misalignment issues, although several months of expander wear is common. The doctor adjusts the expander as needed and you check in regularly.
Even after you achieve optimal expansion, the expander may stay in place for several more months to allow new bone to grow in the gap to ensure permanent stabilization. In general, even with extended wear, it’s common for expanders to be worn from three to six months.