A palatal expander is a device designed to help us do that. Palatal expanders create more space in a child's mouth by gradually widening the upper jaw.
In a well-lit area tip, the patients head back.
Place the key in the hole until it is firmly in place.
Pushing the key towards the back of the mouth, you will notice the fender will rotate and the new hole will appear. The rotation stops when the key meets the back of the expander.
By pushing back and down towards the tongue, remove the key. The next hole for insertion of the key should now be visible.