Exploring Factors Influencing Polymerization Shrinkage in Dental Composite Resin: Insights and Strategies for Enhanced Performance

Dental composite resins are extensively used in restorative dentistry owing to their favorable esthetics, durability, and versatility. Nevertheless, polymerization shrinkage during curing remains a major limitation, as it can lead to microgap formation, bacterial infiltration, and subsequent clinical complications. This review critically discusses four key factors influencing polymerization shrinkage in dental composite systems: expandable monomers, filler systems, ring-opening polymerization mechanisms, and application and curing techniques. Expandable monomers may partially compensate for volumetric shrinkage through structural expansion or water absorption, while inorganic fillers, which do not undergo shrinkage, are incorporated at higher loadings to reduce overall volumetric change without compromising handling and mechanical properties. Ring-opening polymerization systems counteract shrinkage by reducing monomer densification during curing. Furthermore, appropriate application strategies and curing protocols are essential to maximize the effectiveness of these material-based approaches. A comprehensive understanding of these factors is crucial for the development of dental composite materials with reduced polymerization shrinkage and improved clinical performance.