The palatal expander "expands" (or widens) your upper jaw by putting gentle pressure on your upper molars each time an adjustment is made. When you achieve the desired expansion, you will wear the appliance for several months to solidify the expansion and to prevent regression.
In a well-lit area tip the patient's 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.