Expansion Appliances

expansion appliance

Expansion appliance are used to broaden the upper jaw and teeth. They are most commonly used to correct a cross bite – where the upper jaw is narrower than the lower jaw. There are two main types which are used, both of which are bonded/glued to the teeth at the back of the mouth, usually with a ring each side of the back tooth (molar).


In teenage patients, when all the permanent teeth are through, we tend to use an appliance called a Hyrax, which is also bonded to the back teeth with a ring each side, and also glued to two teeth closer to the front of the mouth.  This appliance needs to be turned at home once each night, usually for the first 5-6 weeks after it has been placed.  It would typically remain in place for 3 months before braces are placed on the teeth.

The Hyrax is Consists of a screw attached to the teeth by bands that sit around the molars (back teeth) to hold it in place.

If you have a Hyrax appliance – you will need to turn it once each night with the ‘key’ provided.  Always remember to turn it a FULL turn in the direction of the arrow (toward the back of the mouth).  When removing the key after you’ve completed a turn, it is very important to ‘wiggle’ it out gently so as not to pull it back, as this will cover up the next hole at the front – making it difficult, if not impossible, to turn it the next night.  To fix this problem you will need to find the hole from the previous night (toward the back of the appliance) and place the key into that hole with the wire part bent at an angle, to finish the incomplete turn and therefore correctly line up the new hole at the front.


Commonly used in younger patients, the Quad-Helix is a metal and wire framework shaped like a ‘W’. This sits up in the roof of the patient’s mouth. This appliance does require any adjusting by the patient.  It typically remains in place for 6 months and during this time you would need to come in to have the appliance checked and adjusted every 6-8 weeks.

Fitting your expansion appliance

The teeth at the back of your mouth are very close together, making it difficult to fit bands on your molars. The first step in the fitting process is to place separators (also called spacers) between the back teeth to make room for bands. Separators are small blue rubber balls which apply a light pressure on the teeth, moving them apart slightly. Separators will be placed one week before expansion appliance is fitted.

Managing your expansion appliance

A few helpful hints to help you manage your expansion appliance:

  • Firstly, you will find that you talk a little funny, especially in the beginning – this won’t last very long as your tongue will get used to the appliance.
  • You may also find that your saliva flow will increase initially – this is entirely normal and will settle after a few days.  It is just the way your mouth adapts to something new and different.
  • Do not rub your tongue on the appliance repeatedly. Your tongue will get sore
  • Keep your fingers out. Appliances can be bent and become uncomfortable
  • It is important to make sure that you keep your appliance and teeth squeaky clean so as to avoid any decay and to keep your gums healthy, cleanliness helps make your adjustments more comfortable.

Please avoid all sticky foods as this can damage or dislodge your appliance.

Popping the Band Back On

If you are using an expansion appliance, the band may simply ‘pop’ off the tooth. Try placing the band directly over the tooth to which it was attached and push it back onto the tooth. It may help to look at the other side of the mouth and copy what you can see.

Popping the band back over the tooth will make it more comfortable and keep the appliance out of harm’s way. The band should stay on the tooth by itself, avoid eating hard or sticky foods to prevent the band becoming loose again.

Once the band is safely over the tooth, we recommend calling our receptionists to advise them of the issue.

 Pain Relief

You can seek relief through a mild analgesic, such as Nurofen or Panadol. Remember to ask your parents first and always follow the directions on the packet, or talk to a pharmacist for further advice.

Stick to eating soft foods such as yoghurt, banana or soup to reduce any further discomfort.

The pain should usually settle after 2-3 days.

Orthodontic Wax

Often a new appliance will rub on the cheeks, tongue or gums which can be uncomfortable or annoying. If so, we recommend using some of the Orthodontic Wax, provided by your orthodontist, to assist.  This is especially helpful in the first week or two after your appliance is fitted.

If the appliance rubs or causes any ulcers just roll up a small piece of wax, dry the area that is causing the sore spot with a tissue and push some wax over it.

To help the healing process we recommend rinsing your mouth out with warm salty water as well.

Don’t worry if you get marks on your tongue as this is normal and they will disappear once the appliance is removed.

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