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Expanders and other appliances
Your expander: what to expect
How an expander widens the top jaw, what the turning routine is like, and the two weeks it takes to feel normal.
Written by the team at Milk Orthodontics
An expander (a palatal expander) sits across the roof of the mouth, fixed to the back teeth, and gently widens the top jaw over a few weeks. A small key turns it a little at a time. It feels enormous on day one, speech is odd for a few days, and by the end of the second week most children forget it is there.
Why we use one
The top jaw is two halves joined down the middle, and in a growing child that join is still soft. When the top jaw is narrower than the bottom, the back teeth bite inside the lower ones (a crossbite) and the jaw can shift sideways to cope. Widening the top jaw while the join is soft fixes the width properly, makes room for crowded teeth, and often makes later treatment shorter.
A space opening between the front teeth during turning is expected. It means the two halves are moving apart. It closes on its own over the following weeks, or with braces later.
Turning it
We give you a card with exactly how many turns and how often. Follow the card, not a guess. Turning works best at the same time each day, with the child lying back and their head in a lap so you can see clearly.
- Find the hole
Insert the key into the hole at the front of the screw. It should slot in fully.
- Push back
Push the key firmly towards the back of the mouth until the next hole appears at the front. That is one turn.
- Remove downwards
Take the key out by pulling it down and out, not back, so it does not undo the turn.
- Tick the card
Mark the turn off. If a turn is missed, do not double up the next day; add it to the end.
Completely normal
- Pressure across the roof of the mouth and the nose for a few minutes after each turn.
- A gap appearing between the front teeth. It closes later.
- Speech sounding different for a few days, and more saliva at first.
- Food catching around the expander. A water bottle after meals and a careful brush sort it out.
Message us if
- The key will not go in, or the screw will not turn.
- The expander feels loose on one side, or rocks.
- A sore spot on the roof of the mouth is not settling.
- You have lost count of the turns.
Call us on (09)520 1880 or email hello@milkorthodontics.co.nz.
Common questions
How long does it stay in?
Turning usually takes two to four weeks. The expander then stays in place, without turning, for several months while the new width firms up. We will tell you the plan for your child.
Can they eat normally?
Soft foods for the first few days, then most things. Avoid sticky and very hard foods, which can loosen it. Chewing gum is off the menu.
Two weeks of odd, then it is simply part of the day.
Last reviewed August 2026