Maxillary Expander

What is a Maxillary Expander?

A maxillary expander, also known as a rapid palatal expander, “RPE,” or spacer, is an orthodontic device that widens the upper jaw. An expander corrects certain bite problems and creates space for over-crowded teeth.

maxillary expander vacaville orthodontics
This is a sample maxillary expander. The one you will have in your mouth from our Vacaville office will be even smaller.

How Does a Maxillary Expander Work?

The expander attaches to the upper molars and sits off the roof of the mouth.  It gently applies pressure to the upper jaw bones, specifically the mid-palatal suture. This suture is a flexible joint that connects the two halves of the upper jawbone. This suture is not yet fused in children and young teenagers, which makes it easier to widen the jaw. In comparison, an adult’s suture has fused and can not to expand.

By turning the screw on the expander, the two halves of the upper jawbone separate little by little. This process creates space and stimulates bone growth in the palate. As a result, the upper jaw gradually expands, which makes more space for teeth and corrects the bite.

Who Needs a Maxillary Expander?

Expanders are primarily recommended for children and young teens who have narrow dental arches or a posterior crossbite. A narrow upper jaw can cause overcrowding of teeth, an improper bite, linked to breathing difficulties, and even impacting facial aesthetics. An expander addresses these issues and creates a stable foundation for further orthodontic treatment.

In adults, the mid-palatal suture is fused and will no longer expand. If that is the case, a maxillary expander is placed in conjunction with jaw surgery to widen the upper arch.

The Treatment Process:

maxillary expander vacaville orthodontics
This is the same maxillary expander from the front. No one will notice that you have an expander in your mouth.

Expander delivery is a straightforward process. Here is a general overview of what you can expect:

1. Consultation:

  • Your orthodontist will evaluate your dental and facial structure and determine if an RPE is suitable for you.

2. Customization:

  • Afterwards, digital scans of your teeth and mouth are taken to create a customized expander that fits your jaw and teeth.

3. Placement:

  • About 2 weeks later, your expander is fitted and glued in place. It may feel slightly uncomfortable initially, but you will quickly adapt.

4. Activation:

  • Once we glue your expander in place, you will learn how to turn the expansion screw using a special key. Usually, you will usually be instructed to turn the screw once day to gradually widen the jaw.

5. Follow-up:

  • Afterwards, you attend regular appointments to make any necessary adjustments and ensure that the treatment is progressing as planned. Then, braces are usually placed. The expander will remain in place for at least 6 months to allow for your bone to harden. 


Maxillary expanders work like magic to transform smiles. Expanders widen the upper jaw to improve the bite, may improve breathing, and lay the foundation for a beautiful, healthy smile. While the process may seem complex at first, it’s a tried-and-true method that orthodontists have been using for decades to create stunning transformations. Therefore, if you or your child have dental concerns regarding expansion in Vacaville, consult our board-certified orthodontist to determine if an expander can help unlock the full potential of your smile.