Balancing mechanical integrity and healing efficiency: The role of microcapsule loading in self-healing dental resin composites − A Systematic Review

Objective: To evaluate how microcapsule-based self-healing systems influence the balance between healing efficiency and mechanical performance in dental resin composites. Data and sources: This review followed PRISMA guidelines. Comprehensive searches were conducted in PubMed, Scopus, and Web of Science up to January 2026. Preclinical studies (in vitro and in vivo) investigating dental resin composites containing microcapsules (PUF, silica) loaded with healing agents (TEGDMA-DHEPT, DCPD) were included. Key outcomes included fracture toughness recovery, flexural strength, and the relationship between healing efficiency and baseline mechanical performance. Risk of bias was assessed using the RoBDEMAT tool. Study selection: Twenty-two studies met the inclusion criteria. Most used poly(urea-formaldehyde) or silica microcapsules embedded in Bis-GMA/TEGDMA matrices. Self-healing composites demonstrated substantial recovery of mechanical properties, with the highest reported healing efficiency reaching 76% in a specific PUF-based formulation, while other systems showed comparatively lower recovery levels. Several formulations also demonstrated enhanced fatigue resistance and additional antibacterial or remineralizing effects. Cytocompatibility was generally acceptable in fibroblast assays; however, heterogeneity in materials and methods limited direct comparisons and precluded meta-analysis. Conclusion: Optimal performance was consistently achieved at microcapsule loadings of approximately 5–15 wt%, where substantial mechanical recovery (≈60–75%) was obtained without compromising baseline properties. While current preclinical evidence supports their efficacy, further standardization, in vivo validation, and translational research are needed to support clinical adoption.