An orthodontic system includes a dental appliance and an auxiliary arrangement unit. The dental appliance includes a main body defining a receiving space for receiving at least a portion of a dentition of a user therein. The main body is formed with a main projection projecting outwardly away from the receiving space. The auxiliary arrangement unit includes an attaching member to be bonded to a tooth of the dentition, and a restraining member interconnecting the main projection and the attaching member for moving the tooth toward the main projection.
