Development and pre-clinical evaluation of an isosorbide-based pit and fissure sealant achieving low polymerization shrinkage and high biocompatibility

Objectives: Resin-based sealants (RBSs) are widely used to prevent pit and fissure caries in clinical dentistry. However, their high density of C=C double bonds leads to volumetric shrinkage during photo-polymerization, which may compromise enamel bonding. Additionally, the biosafety of commonly used monomers such as bisphenol A glycerolate dimethacrylate (bis-GMA) and triethylene glycol dimethacrylate (TEGDMA) remains a concern due to potential health risks in adolescent patients. This study aimed to develop a bis-GMA- and TEGDMA-free pit and fissure sealant to address these limitations. Methods: A novel family of isosorbide-derived dental sealants (ISDSs) was developed using a synthesized isosorbide-based matrix, bis(2-(methacryloyloxy)ethyl) disuccinate isosorbide (IBMEDS), and a diluent, bis(2-methylacrylate) isosorbide (IBM). The performance of ISDS was evaluated against the commercial Clinpro™ sealant in terms of polymerization shrinkage, cytotoxicity, physicochemical properties, microleakage resistance, and stability of the sealed area under artificial aging conditions. Results: Compared with Clinpro, ISDS exhibited a 34% reduction in polymerization shrinkage and a more than sevenfold increase in L929 cell viability, attributed to its bio-based structure and low double-bond density. Moreover, ISDS demonstrated superior physicochemical properties, including higher shear bond strength, more effective marginal adaptation to enamel, lower water absorption and solubility, and more sustained and stable long-term fluoride release, while maintaining comparable microleakage resistance. Conclusion: A fully bio-based, fluoride-containing isosorbide-derived dental sealant (ISDS) was developed to overcome the polymerization shrinkage and biocompatibility limitations of conventional resin-based sealants. This novel sealant offers enhanced long-term stability, excellent biocompatibility, improved marginal adaptation, and sustained fluoride release, representing a safer and more effective alternative for caries prevention in children and adolescents.