Traditional removable appliances consist of an acrylic plate with clasps to hold the plate, and springs or screws or bite planes to move the teeth.
They are mostly used in early orthodontic treatments for children such as to correct a single tooth or expanding the dental arch or to correct deep bites. Sometimes they are used prior to fixed appliances. They are used far less often nowadays, as they are very limited in the type of orthodontic tooth movement which they can achieve.
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