On young patients, removable expansion appliances are intended to develop the arches to their full potential, providing room for all teeth to attain proper alignment and occlusion. Expansion screws are adjusted in the same manner as described previously. However, the frequency of adjustment can vary with application. Appliances are ideally worn twenty-four hours a day and, may also be worn at meal time. Lack of retention on subsequent visits may indicate a need for additional wearing time. Patient education and cooperation are essential to successful improvement with removable appliances. The patient (and parents) should understand that improvement depends directly on faithful and consistent wear.
Schwarz arch development
appliance utilizes a large expansion screw mid-palate. The acrylic is sectioned in the center to exert an equal and opposite bilateral force. Expansion screws are usually adjusted once each week by the patient or parent. Patient education and calendar books are helpful tools to assist the patient in proper cleaning and adjustment frequency. At each visit of the patient, the labial bow is relieved from contact with the anteriors to avoid impingement.
On permanent dentition cases
or when second molars are present, a second expansion screw can be added for increased stability. Pressure for expansion can be evenly distributed both interiorly and posterior. Adjusting both expansion screws with the same frequency prevents binding. Periodic removal of the palatal acrylic in the deepest portion of the vault may be necessary to keep pace with arch development.
gears can provide both a posterior bilateral force as well as pressure for anterior development. The expansion gear is provided with two sets of adjustment openings, allowing independent action in each direction. This appliance approach is used extensively on cases involving insufficient cuspid space. Can be made for the upper or lower arch.
The Fan or Hinge Gear expansion
appliance is a frequent appliance choice to create intercanine space in cases of minor crowding. With the hinge positioned adjacent to the molars, the greatest appliance opening occurs at the anterior. Although finger springs can be included, Doctors often find the anteriors align as the acrylic places pressure on the lingual, while the labial bow serves as a fulcrum.