Download general guidelines for expansion screw activation

GENERAL GUIDELINES
FOR
EXPANSION SCREW ACTIVATION
Please note that different manufacturers may have specific instructions - Consult your vendor as needed
IT TAKES BETWEEN 4-12 ¼-TURN ACTIVATIONS
SINGLE MIDLINE EXPANSION SCREW
TO
IN A
PRODUCE 1MM
OF
LINEAR CHANGE.
REMOVABLE APPLIANCE
• Typical rate of activation is one (1) ¼ turn every 5-7 days.
• Most screws we use in mid-palate applications require five (5) activations per 1mm.
• There is no down side to going slower, rather than taking longer to get the job done.
• It is not uncommon to go twice as fast, but you must watch out for the appliance outpacing the
patient’s physiological potential for change.
• If compliance lags or the body is a little too slow to respond, the appliance will be fitting
progressively worse as the activation is continued.
• Going too fast will hinder retention.
ONE TOOTH EXPANSION SCREW
• Typical rate of activation is two (2) ¼ turns every 5-7 days.
• Most screws we use in one tooth applications require 12 activations per 1mm.
• The same slower vs. faster rationale applies.
FIXED SUTURAL EXPANDERS
• Typical rate of activation is one (1) per day.
Digital Orthodontic Lab Services
• Requires four (4) activations per 1mm.
• Not uncommon to fo twice as fast or half as fast.
• Going too fast may damage periodontal membrane or roots of the teeth.
• Going too slow may result in producing more dento-alveolar change and less sutural split
than normally desired.
FIXED EXPANDERS
ON THE
MANDIBLE
• Typical rate of activation is one (1) every 5-7 days.
• Requires four (4) activations per 1mm.
• Not uncommon to go twice as fast or half as fast.
• Going too fast may damage periodontal membrane or roots of the teeth.
• No down side in going too slowly other than longer treatment.
FAN TYPE FIXED EXPANDERS
ON THE
MAXILLA
• The same considerations as for Fixed Sutural Expanders generally apply. However, additional
consideration must be given to the activation rate predicated on the hinge location.
• Activation of 2-3 times per week is reasonable.
• Greater anterior-posterior distance between the front of the appliance and the hinge will produce
a dramatically greater expansion at the front of the appliance versus the mid or posterior portion.
MICRO SCREW
• Typical rate of activation is one (1) full rotation every 5-7 days or two (2) turns per week.
• One complete revolution of the screw equals 0.6mm of activation.
• Requires a small screw driver (eye glass style) to activate - available for additional fee.
• Available with 4mm (standard), 6mm, or 8mm spring-loaded inserts. Larger size inserts provided
for additional movement.
• Over activation of the screw could hinder retention.
CONTACT LAB CUSTOMER SERVICE 716.871.1161
FOR
MORE INFORMATION