Movable appliance: it is generally used to correct simple mistakes and deformities of deciduous teeth and dentition, or to correct them with fixed appliances. The patient can take it down by himself.

Fixed chair orthosis: the most commonly used orthosis. The patient can't take it off himself.

Functional chair appliance: it is mainly used for children who are still at the peak of growth and development during or just after tooth replacement. The functional appliance can correct skeletal malocclusion and deformity.

Orthognathic surgery: Serious dentofacial deformities, such as maxillary protrusion, maxillary retraction, mandibular protrusion and mandibular retraction, need to be corrected by surgery and orthodontics if simple correction cannot be solved.