From Passive Matrices to Bioresponsive Interfaces: Polymer-Based Biomaterials for Oral Soft Tissue Augmentation

Soft tissue deficiencies around teeth and dental implants remain a common clinical challenge affecting aesthetics, tissue stability, and long-term maintenance. Polymer-based substitutes reduce donor-site morbidity compared with autogenous connective tissue grafts, but comparative evidence frequently shows lower gains in mucosal thickness and keratinized tissue dimensions. This narrative review examines the biological and material factors that may limit the performance of current soft tissue substitutes and evaluates strategies aimed at overcoming these limitations. Particular attention is given to the mismatch between healing dynamics and passive material behavior, including early burst release of bioactive agents, degradation uncoupled from cellular colonization, delivery kinetics that are not designed to respond to the state of the wound, and limited dose control. Current approaches such as platelet concentrates, recombinant growth factors, affinity-based delivery, covalent immobilization, and cell-seeded matrices can improve selected healing outcomes, but their effects remain strongly dependent on the carrier and have not consistently matched the gains in mucosal thickness and keratinized tissue width obtained with autogenous grafts. Stimuli-responsive and bioresponsive polymer systems offer a potential strategy for making degradation or release depend on the local wound state, although their application in oral soft tissue augmentation remains predominantly preclinical. Future research should focus on polymer–cell and polymer–bioactive agent systems in which degradation, cellular colonization, signal delivery, and mechanical performance are better aligned with tissue healing and long-term maintenance.