Abstract: The appliance comprises a machined or cast interface that secures the appliance to bone by means of an appliance connection and a bone connection. The connection is a cylindrical sleeve into which each arm of the expansion appliance is inserted. This connection is maintained by crimping the sleeve over the easily modified activating rods of the expansion appliance, thus preventing separation or rotation of the device. The bone connection is a threaded hole in the connector sleeve into which a self-drilling screw is inserted. The screw engages the bone in a manner determined by the design and location of the expansion appliance.