When only two to three millimeters of lost space needs to be regained (and the edentulous area is at least 8mm), the Split Acrylic-Saddle Appliance is a good choice. Opening the wire loops prior to insertion activates the device. Periodic adjustment is typically required to help keep the appliance active. Note: The edentulous region must be at least 8mm in length in order to accommodate the acrylic and wire loops that make up the split saddle.