This appliance utilizes the Nickel Titanium Memory Screw for lateral development along with Herbst Hinges. This appliance is excellent for correction of skeletal class II malocclusions. Proper construction of this appliance requires a preset construction bite showing the patient in the corrected (Class I) position.

The effectiveness of this appliance, as well as with all Herbst designs, is enhanced if the transverse deficiencies are addressed first. This is especially true in cases where severe constriction of the dental arches exists. However, if both Class II and lateral deficiencies must be corrected simultaneously, the MemRx EH is a good appliance choice where fixed treatment is preferred.

Once the appliance is cemented into the mouth, the expansion screw may be adjusted 5-6 turns immediately. This will load the internal NiTi coil springs. Expansion is expressed in a gentle, more consistent manner than traditional RPE screws. A single screw can expand up to 10 millimeters. In cases where severe constriction exists, an additional appliance may be necessary.