When patient compliance is an issue, a fixed appliance is always preferred. Arnold Expander develops the arch using a spring-loaded split-lingual arch housed in a tube. Tension on the spring coil is set before the appliance is initially placed. Further adjustment is not usually necessary. Once the desired space has been created, the appliance can be made passive by carefully pinching the tube tight against the wire with a pair of heavy wire cutters or tube crimping pliers. The Arnold Expander is often used in conjunction with a full arch, fixed technique. In such cases, make sure to ask the lab to fabricate the appliance with molar tubes soldered to the bands. (Hint: Because it's always difficult to cement a pre-activated spring loaded appliance, ask the lab to return the appliance to you on the model. This allows you to tie the appliance together with floss, thus controlling the spring action prior to cementation.