In Vitro Study: Sch-79797 Adhesive Against S. Mutans Biofilm

Composite resin restorations are central to caries therapy, but secondary caries is a major cause of failure due to resin shrinkage and biofilm adhesion. Developing antibacterial dental adhesives to reduce bacterial colonization is a promising strategy. SCH-79797, a novel dual-target antimicrobial agent, shows excellent antimicrobial properties. This study evaluates whether its modified dental adhesive retains stable adhesive properties while exhibiting antimicrobial effects. Shear bond strength of the modified adhesive was tested using an Electronic Universal Material Testing Machine, and fracture surfaces were analyzed via Scanning Electron Microscopy. Monomer conversion and water contact angle were measured using Fourier Transform Infrared Spectroscopy and a Contact Angle Meter. Cytotoxicity was assessed via MTT assay and live/dead staining on L929 cells. Biofilm inhibition was evaluated through CFU counting, MTT assay, and Scanning Electron Microscopy. Extracellular polysaccharide and acid production were analyzed using anthrone assay and pH/lactic acid assays. SCH-79797-modified adhesives at 0.5% or lower concentrations showed no significant changes in adhesive properties and exhibited biocompatibility. The modified adhesive significantly reduced Streptococcus mutans biofilm biomass, metabolic activity, lactate production, and extracellular polysaccharide formation. SCH-79797-modified adhesives demonstrate in vitro caries resistance potential against cariogenic bacteria, offering a promising strategy for reducing secondary caries.