Surgically Assisted Rapid Palatal Expansion (SARPE) Procedure

Surgically-Assisted Rapid Palatal Expansion(SARPE Procedure)

In a normal bite (occlusion), the upper teeth overlap the lower teeth by about half the width of the upper tooth.  When there is large discrepancy of overlap due to transverse (right to left) jaw growth problems, the upper teeth can reside  on the inside of the lower teeth in the back sections of the mouth. The result of this is called a cross-bite.  We correct posterior cross-bites as soon as we see them because we can obtain more room for other un-erupted teeth.  Also, a posterior cross-bite, if it is only on one side, can cause the lower jaw to grow asymmetrically to that side.  Therefore, correction of a posterior cross-bite helps prevent asymmetrical growth of the lower jaw.   Rapid palatal expansion is often used to correct this problem.  Since palatal expansion involves separating the bones that make up the hard palate and join in the midline (called the palatal suture), it is better to perform this procedure at a younger age before the palatal suture becomes fused.  The bones of the palate begin to fuse at the onset of puberty.  Therefore, rapid palatal expansion should be performed between the ages of 7 – 11.  If it is required after the age of 11, a surgically assisted rapid palatal expansion (SARPE) procedure is necessary.

What if I am over the age of 11?

With adolescents and adults, Dr. Mueller can expand the maxilla by using an RPE and having surgery performed. This procedure is called Surgically Assisted Rapid Palatal Expander (SARPE). During the procedure, Dr. Mueller opens the palatal suture with side releasing incisions and activates the RPE appliance.   Patients or a caregiver will turn the expander with a key after the surgery.  The key is provided by your orthodontist, and Dr. Mueller will instruct you on how and when to turn the key.  As the key is turned, the gentle “pulling pressure” that the bone realizes actually stimulates the bones to grow as the bones are separated.

How long do I have to turn the key?


Gap (diastema) being created by the expander.

After Dr. Mueller determines you that you have turned the expander enough, and the cross-bite is eliminated, the RPE is left in place for about three months. This is so that the palatal suture can be closed with new bone formation and become stable. If an RPE is removed early, some of the width gained could be lost.

During the expansion, a space (a gap called a diastema) will develop between the central incisors. This is normal and expected.  When it is time for the RPE to be removed, your orthodontist will then put braces on your upper teeth and will begin to close the gap.

Rapid Palatal Expander

Rapid Palatal Expander (RPE) is an upper jaw (maxilla) appliance that places pressure on the upper jaw by turning a midline screw.  The pressure separates the mid palatal suture thus making the maxilla wider, which can correct cross-bites and create space.  RPEs are used often to correct posterior cross-bites.


The RPE is made by an orthodontic lab to custom-fit your teeth.

How will the palatal expander feel?

After you turn the expander you will feel pressure.  The pressure lasts for about 4 to 5 minutes. The pressure feels like taking your thumb and pushing on your teeth.  So, an expander is not painful.  You will have some pressure after activation for a few minutes and then it dissipates.  Dr. Mueller will see you periodically after the surgery to monitor the healing and expansion.