Background <p>Soft tissue expanders (STEs) are used in reconstructive surgeries to stretch tissues gradually, providing space for implants or facilitating bone augmentation. These devices have evolved from traditional silicone balloon expanders to modern self-inflating osmotic systems, which offer more controlled and less invasive expansion. This review explores the advancements in STEs, particularly the use of hydrogels, and their applications in clinical settings.</p> Main text <p>Recent studies indicate that tissue expansion facilitates soft tissue growth through mechanical stretch and biological creep, enhancing vascularity and promoting fibroblast proliferation. The extracellular matrix transmits mechanical forces that influence cell behavior, while excessive pressure may lead to bone resorption, soft tissue necrosis, and expander exposure. Modern STEs include hydrogel-based, self-inflating types that absorb interstitial fluids to enable gradual expansion. These devices offer advantages such as biocompatibility, minimal scarring, and simplified surgical procedures. However, complications such as temporary deformity, hypoxia, allergic reactions, and infection remain important clinical concerns.</p> Conclusion <p>Hydrogels in STEs need to balance effective expansion with minimal toxicity or morbidity. A key challenge is finding a patient-compliant, economic solution for tissue expansion before bone augmentation. Proper understanding and application of STEs can lead to&#xa0;successful outcomes in reconstructive surgery. Despite&#xa0;the&#xa0;usefulness of STEs, a comprehensive synthesis of their underlying biological mechanisms, clinical applications, and recent research developments is currently lacking. This review aims to fill that gap by summarizing the molecular and physical mechanisms of soft tissue growth, highlighting key factors that regulate expansion, and providing an updated overview of STEs and hydrogel technologies.</p>