They can be active and functional.
This type of orthodontic therapy is applied in children of age 8-14 or in the period of teeth shift or so called Mixed dentition. With mobile appliance, good therapy plan and great patient-parent cooperation really good results can be made so fixed prosthetic therapy doesn’t even need to be used at all.
Early therapy has unnumbered advantages, fore an anomaly can often be resolved before it developers, avoiding that way longer, more complicated and expensive treatments.