This study systematically reviews the latest research advances in clear aligners across materials science, clinical treatment outcomes, and impacts on oral health. In materials science, research focuses on membrane biocompatibility, development of bio/smart composite aligners, and direct printing technology for clear aligners. Although mainstream materials are generally safe, some still harbor cytotoxic risks. Smart composite materials offer novel strategies for monitoring and preventing enamel demineralization and bacterial biofilm formation by integrating sensors or incorporating antimicrobial agents. Directly printed aligner technology demonstrates significant potential due to its customizability and high precision. Regarding clinical efficacy, evidence indicates that clear aligners achieve comparable results with fixed appliances for mild-to-moderate malocclusions, though their efficiency and effectiveness are slightly inferior in complex extraction cases. Regarding specific tooth movement control, arch expansion primarily relies on crown inclination, yielding results below design expectations; molar distalization achievement is also limited. Studies refute the notion that a specific “bite-ramp effect” causes mandibular counterclockwise rotation. For skeletal class Ⅱ malocclusions in children, clear aligners combined with functional orthodontic modules show promising applications, though evidence levels require further enhancement. Regarding oral health impacts, multiple studies confirm that clear aligners effectively reduce enamel demineralization risk, decrease plaque accumulation, and improve periodontal health compared with fixed appliances. In summary, clear aligner technology has advanced toward great precision, efficiency, and personalization. However, clinicians must recognize its tool-like nature. Successful treatment fundamentally relies on comprehensive diagnosis, appropriate treatment planning, and meticulous clinical execution.
