A method includes receiving, with a computer system, a digital representation of a 3D tooth structure providing initial positions of one or more teeth of a patient, determining dimensions and shapes of a removable dental appliance, the dimensions and shapes being configured to reposition the one or more teeth from their initial positions to adjusted positions when the dental appliance is worn, and transmitting a representation of the dental appliance to a computer-aided manufacturing system. The dental appliance includes an appliance body configured to surround two or more teeth of the patient with a facial portion configured to register with facial sides of the surrounded teeth, and a lingual portion configured to register with lingual sides of the surrounded teeth. The appliance body is configured such that occlusal surfaces of the surrounded teeth of the patient are exposed when the removable dental appliance is worn by the patient.