With the increasing demand for beauty and health, clear aligners (CAs) have been widely applied among patients with malocclusion. However, patients treated with CAs also face some potential complications, such as demineralization, dental caries, and periodontal diseases. In addition, some patients have additional needs to improve their quality of life, such as bleaching teeth. In order to prevent or solve these problems, the modification of CAs is a promising method because their extensive long-term contact with tooth surfaces makes them ideal devices for implementing adjuvant medical functions.

In this review, we discuss various advanced CAs with medical functions based on the clinical needs of patients. As far as we know, the additional functions of CAs mainly include antibacterial, remineralization, whitening, and accelerating tooth movement. These functions are achieved by two major pathways, the combination of CAs with drugs/biomaterials and increasing the capacity or affinity of drugs. In addition, we discuss the current limitations of in vitro experiments which are designed to explore the effectiveness and properties of novel CAs, and the challenges of bringing a multifunctional appliance from proposal to clinical application. At the end of this review, we provide insights into the broader prospects for the improvement of CAs.