Abstract Four-dimensional (4D) printing is an emerging additive manufacturing technology that uses stimuli-responsive materials capable of time-dependent transformation. In orthodontics, it offers the potential to develop adaptive, patient-specific appliances with controlled mechanical behavior. Smart materials, particularly shape memory polymers, are central to this concept due to their ability to respond to external stimuli such as temperature or light. This scoping review aims to map the current evidence on 4D printing and smart materials in orthodontics, focusing on material development, activation mechanisms, and potential clinical applications, including clear aligner therapy. A systematic search was conducted in PubMed and Scopus for studies published between 2016 and 2026, following PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Scoping Reviews) guidelines. From 482 identified records, 32 studies met the inclusion criteria. Data were synthesized into three main categories: orthodontic applications of 4D printing, smart material development, and related biomedical applications. Most included studies described experimental or conceptual applications of shape memory polymers in adaptive orthodontic systems, suggesting potential for time-dependent force delivery and improved treatment personalization. However, clinical evidence remains limited. Key limitations include the predominance of in vitro studies, lack of standardization, and absence of long-term clinical validation. Despite these challenges, 4D printing represents a promising approach for advancing personalized orthodontic treatment.
Oravcová et al. (Tue,) studied this question.
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