1. Functional appliance: This kind of appliance is mainly used for children who are still at the peak of growth and development during or just after tooth replacement. Functional appliances can correct skeletal malocclusion.

2. Movable appliance: Usually, this appliance is used to correct simple malocclusion when deciduous teeth and dentition are replaced, or it can be corrected with fixed appliance, and the patient can take it off.

3, fixed appliance: the most commonly used dental appliance, worn for about a year, during which the child should review regularly and can not be taken off.