Mandibular (Lower) Expander

What the Appliance Does
e-archThe mandibular (lower) expander is spring activated. This appliance pushes the lower molars outward and backward. The sides of the lower arch also move laterally. Note: the lower expander has two halves.

Activation of the Appliance
This appliance is spring loaded and self activating. Nothing is required on the patient’s part in order for the appliance to work.

What to Expect
Some initial irritation to the tongue and the gum tissue can be expected. There is minimal discomfort associated with this appliance. As the expander works, it is common to have the mandibular (lower) canines flare out laterally.

  • Spacing between the front teeth may become apparent. The crowded lower front teeth may appear to unwind.


  • Brush the expander with tooth paste and toothbrush.
  • A proxy brush can be used to remove any larger pieces of food trapped between the teeth and the expander.
  • Using a Waterpik™ can be beneficial as a cleaning aid. Lowest setting only.
  • Flossing around the teeth is recommended and possible.

Things to Watch For

  • Sometimes the appliance may come off the back of the teeth. Should this occur, you will know because the back band/brace will move up and down. If half of the expander comes completely off the tooth, save that section and call the office for an appointment. Usually the half remaining is stable and will not cause discomfort.
  • If the sides of the expansion wire impinge on the gum tissue and do not cause any pain/discomfort, there is no need for concern. If the side of the expander impinges on the gum causing pain, please call the office.
  • When the lower expander is fully expanded, very rarely will the two halves of the expander completely separate. Should the expander come completely apart. Save any of the parts and call the office to schedule during normal office hours.
  • When the mandibular expander is first placed, sometimes the side wires may appear to rise higher above the side teeth. If there is no difficulty with chewing, there is no need for concern.
  • Please watch that the patient does not play with the front of the expander by placing their tongue under the front portion of the expander.