A narrow maxilla is one of the most common orthodontic problems seen in a developing child. Left untreated, it can lead to severe crowding and cause the occurrence of an anterior or posterior crossbite. It can also inhibit the normal development of the mandible, creating a skeletal Class II. The Schwarz appliance is the most frequently used removable appliance to develop a narrow arch. This appliance works by turning the expansion screw in the center of the palate one-quarter turn once or twice a week.

This slow expansion allows the acrylic to place pressure on both the palatal tissue and the teeth in a lateral direction. As the arch develops the palate will drop, so adjustment of the acrylic in the palatal region will be necessary throughout treatment. Although removable appliances tend to tip teeth as they are moved buccally, expansion is slow enough that normal occlusal function is usually sufficient to maintain their normal inclination. In this example, individual recurved springs are used to move #7 and #10 into position as space is created. Note - These appliances can be made in different colors, designs and with decals. (Please see color chart in the “Reference Section”) This is a great way to motivate your patients.