Palatal expander

Two AAO glossary entries for the palatal expander

The palatal expander has two entries in the Glossary of Orthodontic Terms of the American Association of Orthodontists (AAO). Under Palatal Expander, the AAO glossary gives “A fixed or removable orthodontic appliance used to make the upper jaw wider”; under the shorter Expander, it gives “An orthodontic appliance that can widen the jaws.”

Palatal refers to the palate, the roof of the mouth, which is where the device sits. The everyday names are expander and palate expander, the second being the form the AAO’s own FAQ uses.

How an orthodontist uses a palatal expander

A palatal expander is described on the AAO’s expander page, dated March 25, 2026, by where it sits and how it is adjusted: “The device sits across the roof of the mouth, also known as the palate and is attached to the upper back teeth. Some expanders are adjusted by turning a small screw to gradually widen the upper jaw. Others use built-in springs or wires and don’t require turning.”

Whether a child needs one is the orthodontist’s judgment, and the AAO says plainly that “Not every patient will need a palatal expander.” The AAO’s FAQ names one situation where the device comes up: “If a child’s upper jaw is too narrow, so that the permanent teeth do not have room to come in, treatment could consist of a palate expander to widen the jaw.”

How often a screw-type expander is turned is part of the instructions the orthodontist gives the family.

Expanders in the practice’s early treatment

Expanders come first in the practice’s own list of tools for early treatment, which in its words is expanders, Invisalign® First, braces, and habit appliances. Dr. Kunik’s approach to early treatment is very conservative.

The expander is set beside the other early-treatment tools, with what the evidence says about early treatment, on the page about orthodontics for children and teens. Mixed dentition, the stage when baby and permanent teeth are in the mouth together, is defined in the glossary of orthodontic words.