Low-shrinkage-stress fluorinated methacrylate-thiol-ene resin composite: Bacterial anti-adhesion activity, physical properties, and biocompatibility.

OBJECTIVE: To evaluate the bacterial anti-adhesion properties, marginal sealing ability, physicochemical performance, and in vivo biocompatibility of a novel fluorinated methacrylate-thiol-ene dental resin composite (DST) designed to reduce polymerization shrinkage stress and secondary caries risk.

METHODS: DST was prepared using a thiol-ene step-growth polymerization system. Bacterial anti-adhesion was assessed using saliva-derived human dental plaque biofilms by colony-forming unit counting, confocal laser scanning microscopy (CLSM), scanning electron microscopy, crystal violet staining, and MTT assay. Microleakage was evaluated in modified Class II restorations using rhodamine B dye and CLSM. Wear resistance, surface roughness, contact angle, surface free energy, and diametral tensile strength were measured. In vivo biocompatibility was evaluated in Wistar rats through hematological, biochemical, and histopathological analyses.

RESULTS: DST significantly reduced total bacterial and streptococcal adhesion compared with conventional composites, without affecting biofilm metabolic activity. DST-1 exhibited significantly lower microleakage scores, enhanced wear resistance, lower surface roughness, and reduced surface free energy. Although a modest reduction in tensile strength was observed, polishing performance and hydrophobicity were improved. No adverse systemic or tissue responses were detected in vivo.

CONCLUSIONS: DST-1 demonstrates effective inhibition of dental plaque biofilm adhesion, improved marginal sealing, favorable mechanical performance, and excellent biocompatibility, indicating potential to reduce the risk of secondary caries and enhance restoration longevity.

CLINICAL SIGNIFICANCE: By combining low polymerization shrinkage stress with bacterial anti-adhesion properties, this resin composite addresses key factors contributing to secondary caries. Its favorable marginal sealing, wear resistance, polishability, and biocompatibility support its clinical use in durable and aesthetic restorations, potentially improving long-term outcomes of resin-based restorative treatments.