Everything You Need to Know About RME Expanders!

Have you ever wondered what an RME expander is, why it has been recommended, or how it actually works?

Rapid Maxillary Expansion (RME), also known as a palatal expander, is a well-established orthodontic treatment used to widen a narrow upper jaw. By creating additional space and improving the width of the upper jaw, an expander can help correct bite problems, relieve dental crowding and create a healthier foundation for long-term orthodontic treatment.

What is an RME Expander?

An RME expander is a custom-made orthodontic appliance that sits on the roof of the mouth and is attached to the upper molars. The appliance applies gentle, controlled pressure to gradually widen the upper jaw.

The upper jaw develops as two separate halves joined together by a growth plate called the mid-palatal suture. During childhood and early adolescence, this suture has not yet fully fused, allowing the jaw to be widened using light, continuous forces. As the expander gently opens the suture, new bone naturally forms between the two halves of the jaw, resulting in a wider, more stable upper arch.

This is why treatment is generally most effective while a patient is still growing.

Why Might an RME Expander Be Recommended?

An expander may be recommended for a variety of orthodontic reasons, including:

• Correcting a posterior crossbite
• Creating space for crowded teeth
• Reducing the likelihood of future tooth extractions in suitable cases
• Improving the relationship between the upper and lower jaws
• Developing a broader, healthier smile
• Increasing the width of the floor of the nasal cavity, which may improve nasal airflow in some patients

Every patient is different, and an RME expander is only recommended after a comprehensive orthodontic assessment. Expanders may be combined with other orthodontic appliances, depending on specific needs and under the guidance of a specialist orthodontist.

Does an Expander Help with Breathing?

Research has shown that Rapid Maxillary Expansion increases the width of the upper jaw and the floor of the nasal cavity. Some studies have demonstrated improvements in nasal airway dimensions and reduced nasal resistance following expansion.

However, breathing and sleep quality are influenced by many factors, including the nose, adenoids, tonsils, tongue position, allergies and general health. While some patients notice improved nasal breathing following expansion, an RME should not be considered a stand-alone treatment for breathing disorders or obstructive sleep apnoea.

How Long Does an Expander Stay In?

Although the active expansion phase usually takes only a few weeks, the appliance generally remains in place for approximately 6–10 months.

This retention period is essential because it allows new bone to mature within the expanded suture, helping stabilise the result and reduce the risk of relapse.

What is the Process for Getting an RME Expander?

Step 1 – Records and Measurements (Approximately 10 Minutes)

Your orthodontist will take a digital scan of your teeth to fabricate your custom expander. Small orthodontic separators are usually placed between the back teeth to create room for the appliance.

Step 2 – Fitting the Expander (Approximately 10 Minutes)

Around two weeks later, the separators are removed and the custom-made expander is fitted and securely attached to the upper teeth.

Step 3 – Activation

Your orthodontist will demonstrate exactly how to activate the expander and provide detailed instructions. Expansion is carefully monitored throughout treatment to ensure the desired result is achieved safely and predictably.

Frequently Asked Questions

Does wearing an expander hurt?

Most patients experience pressure or tightness for a few minutes after each activation. This sensation is usually mild and settles quickly as the mouth adapts.

Will I notice a gap between my front teeth?

Yes. As the upper jaw widens, it is common for a temporary space to appear between the upper front teeth. This is a normal and expected part of treatment and usually closes spontaneously. 

Can adults have an RME expander?

Traditional Rapid Maxillary Expansion is generally most successful in growing patients. In adults, the mid-palatal suture has usually fused, and alternative expansion techniques—such as MARPE or surgically assisted expansion—may be more appropriate depending on the individual case.

Learn More

If you have been advised that you may need an RME expander, watch our video to learn how the appliance works, what to expect during treatment, and why early intervention can make a significant difference.

If you have any questions, our team would be delighted to help.