One of the most common problems encountered by Orthodontists is dental crowding.  Crowding is a result of there not being enough room in your mouth for all of your teeth.  In children and teenagers the treatment for crowding often involves an appliance to expand the jaws.  Expanding the top jaw also removes any posterior crossbites if present. This may be done with a removable or fixed appliance.

Initially you may find that the appliance will affect your speech and saliva flow. This will reduce with time and practice. Reading out loud will also assist with getting your speech back to normal.

These devices are deigned to expand both your back upper teeth and jaw. When you first receive the appliance it may rub on your cheeks. Place the wax provided to protect your cheeks from becoming sore.

Expanding your appliance

Upon receiving your expanding appliance you will also be provided with a key to adjust your plate according to our instructions.  This key is necessary to make adjustment to your plate that will create the required jaw expansion. Therefore it is important you know how to use the key and follow our instructions carefully on how often to adjust the plate and by how much.

  1. Place the key in the front hole located on the beginning of the arrow.
  2. Push the key in the direction of the arrow until it will go no further. You will feel pressure on your teeth as the appliance expands.
  3. Slide the key out and the new hole should be visible at the beginning of the arrow.
  4. A space between the front teeth may appear and will close naturally a few weeks after stopping the expansion.

If you have any difficulty wearing your appliance or making an expansion turn please contact us as soon as possible.

Twin Block

A twin block is made of two removable plates which fit both the upper and lower teeth. Occasionally they may have springs to move individual teeth and expand the upper jaw.

To fit your twin block you need to correctly position the plates. Once in the correct position use your fingers to gently push against the plastic plate and click it into place.

To remove your twin block use your index finger to pull downwards on the metal clips which are located on the far back sides of the plate. To remove the lower block use your thumbs and push upwards. This technique will help to prevent damage to the delicate wires toward the front of the appliance.


A Herbst appliance is used in growing patients to correct a discrepancy in the position of the top and bottom jaws. It is used to promote growth of the lower jaw in a forward direction whilst applying pressure to the upper jaw in a backward direction.

A tube and rod work together to connect the upper and lower jaws. The appliance is worn full time and does not interfere with opening and closing of the jaws or with eating. You may be required to wear the appliance for 12 months along with braces on your top front teeth.

How to use your Herbst appliance

At first you may notice some tenderness to the teeth and muscles near the appliance.  This is normal and should begin to disappear within a week.  For comfort you may like the cover the arms of your Herbst appliance with the orthodontic wax provided.

If any other parts of the appliance become loose please call our office so we can repair the appliance for you.

Upper Removable Appliance/Plate

An upper removable appliance (plate) is worn for function and removed for cleaning.  It consists of an orthodontic plate which fits to the upper teeth and roof of the mouth.  The appliance may have springs to move individual teeth or an expansion screw to widen the top jaw.  When fitting your URA it is beneficial to look into a mirror so you can correctly position the plate. Once in the correct position use your fingers to push against the plastic and click your plate into place.

How to wear your appliance

In order for your appliance to be effective it should be worn 24 hours a day.  This includes when sleeping and eating soft foods.  The only time it is suggested to remove your appliance is when cleaning your teeth, playing contact sports or swimming, or when eating hard or sticky foods.

Not wearing your appliance not only results in it not being effective at its purpose but it may also result in poor fit. This can be uncomfortable and will prevent you from achieving the best result.

How to care for your appliance

Your appliance should be cleaned everyday with a soft brush under running water.  Ensure that the water is not hot or it may deform your appliance.

To avoid your appliance being lost or broken when it is not in use please store it in the box provided to you.

If you have been fitted with a rapid maxillary appliance, you can brush your teeth normally but you do need to pay special attention to the whole appliance. Brush the screw hole with a soft brush to make it easily visible for the expansion adjustment.