Invisible appliance technology is a novel orthodontic technology that uses computer aided design and polymer materials to achieve a more aesthetic and comfortable treatment. Compared with traditional lip-bracket orthodontic treatments, the greatest advantages of an invisible appliance are aesthetics. In the orthodontic process, the control of the anterior teeth may not be accurate, which often directly affects the patient′s postoperative side appearance; however, in clinical practice, there is still a large deficiency in the control of the anterior tooth torque by an invisible appliance compared to traditional lip-bracket orthodontic treatments. The factors related to the expression efficiency of anterior tooth torque include the combination of morphology and position of different types of brackets and wires, the tooth movement mode and clincheck design. This article reviews the factors that influence lingual orthodontics and clear aligner therapy in the treatment of anterior tooth torque.

More than 20 years have passed since the advent of individualized appliances, which are designed according to the corrective target position. Through a series of digital technology-aided design and production processes, individual appliances have been increasingly recognized and accepted by the public. At present, there are three types of individualized orthodontic appliances: individualized lingual orthodontic appliances, non-bracket invisible appliances and individualized labial appliances. Because of their good effects in orthodontics, these appliances have gradually become mainstream orthodontic treatment tools. However, many doubts persist regarding their use in clinical treatment. This article reviews the development history, design principles and characteristics of the three types of individualized appliances. The results of a literature review showed that CAD/CAM and CBCT provide a hardware foundation for personalized orthodontic appliances that simplifies the therapeutic process. Additionally, individualized appliances also place higher demands on orthodontists. This article could provide references for and help with the clinical selection and use of individualized appliances.