Standard Instructions for Using 
Rapid Palatal Expander

After the patient and parent are instructed how to activate the screw, three 1/4 turns are made at this visit at five minute intervals.  Thereafter the patient makes one 1/4 turn each morning and another 1/4 turn each night.  The patient is seen again at the end of one week to check the progress.  If all goes as planned activation is complete at the end of two weeks.

The appliance is allowed to remain inactive for three months or more for the bone to fill in.  It is best to ligate the screw in place after the proper expansion is achieved, to avoid the possibility of the screw backing up.  It is also a good idea to X-ray the palate before removing the appliance to be sure the suture has filled in with bone.

Each time the swivel key is inserted into the hole in the screw, and turned until the key touches the housing.  That is considered to be one turn.  This is actually only one 1/4 revolution of the entire screw shaft.  For each full revolution of the screw, one mm of expansion is achieved.

 The four type of screws that we use are:

 standard RPE screw
Swivel Keys used to adjust safely in mouth

10 mm maximum expansion @ 44 turns
(this one comes out of the housing 52 turns)

13 mm maximum expansion @ 62 turns
(screw locks and does not exit housing)

Super Screws use a wrench
12 mm
16/18 mm
(each line on screw is 2mm)
(each wrench swing is 1/12 mm)
pdf file of instructions

Fan RPE
distances moved will vary
 dependent on placement in palate

Haas Screw
13mm

              Request a copy of this document.

Return To Top