The RME (Rapid Maxillary Expander) or RPE (Rapid Palatal Expander) is an expander that is used where the upper jaw is too narrow relative to the lower jaw. If an upper jaw expander is required you will usually find that the relationship of the back teeth is reversed, with the upper teeth biting inside of the lower teeth.

Benefits of RME

Widening the upper jaw with the use of a RME for expansion helps to:

  • Achieve a better bite.
  • Correct a functional shift.
  • Create a little more room for any crowded teeth.
  • Improve the nasal airway- a narrow or deep upper jaw may make it harder to breathe through the nose. When widening the upper jaw, the air passages also widen, thus allowing easier breathing through the nose. Once the upper jaw has been expanded, new bone fills the space and helps maintain the increased width.

The difference between a jaw expander and braces is that braces move the teeth, while an expander gently separates and widens the two parts of the upper jaw making more room for crowded teeth and promoting symmetry.

Often there is a shift of the lower jaw to one side to accommodate the narrow upper jaw. This often results in asymmetrical lower jaw growth over time. There are often asymmetries of other facial bones as well.

The most significant reason for expanding the upper jaw using rapid palatal expansion in childhood is to intercept the problem of asymmetrical lower jaw growth before it results in facial asymmetry.

After the jaw expander has been cemented in place, the patient will be required to check it every day and turn the screw as instructed. Parents will need to assist!

Note: treating an underdeveloped lower jaw requires a different procedure and orthodontic measures – To find out more about how an under developed lower jaw can be treated follow the appliances link to “Twin Block” and CBJ.