Introduction: Additive manufacturing has significantly advanced the fabrication of complex structures, with 3D printing offering precision, customization, and reduced waste compared to conventional methods. Building on this foundation, 4D printing introduces time as an additional dimension, allowing printed objects to transform in response to external stimuli such as heat, light, water, stress, or magnetic and electric fields. This innovation expands the potential of additive manufacturing from creating static structures to developing dynamic, stimuli-responsive systems.
The concept of 4D printing was first introduced by Skylar Tibbits in 2012, marking the beginning of research into integrating smart materials with 3D printing technologies. Since then, this field has grown rapidly, opening new possibilities across scientific and industrial domains.

Methods: The success of 4D printing depends on the choice of materials. These can be broadly classified into metals, which provide structural strength; ceramics, offering thermal stability; polymers, particularly shape-memory polymers enabling flexibility and responsiveness; and composites, which combine the advantages of multiple classes to achieve multifunctional performance. Fabrication techniques rely on advanced adaptations of existing 3D printing technologies such as stereolithography (SLA), fused deposition modeling (FDM), and selective laser sintering (SLS). Results: The 4D printing process results in products with several applications, extending from general uses to medical applications such as adaptive prostheses. Within dentistry, its potential is particularly promising, with opportunities for self-adjusting orthodontic aligners, adaptive prosthodontic devices, smart scaffolds for regenerative dentistry, and restorations that respond to the oral environment. Conclusions: Four-dimensional printing represents a transformative step in dentistry, shifting from static to smart solutions.