Synergistic strategy of riboflavin and lipoids to bioengineer resin dentin hybrid layer

The study aimed to synthesize and evaluate the effects of an experimental adhesive system containing different concentrations of riboflavin in combination with Lipoid/phosphatidylcholine solutions on the dentin-bonding interface. Lipoid solutions were prepared in riboflavin (RF) experimental self-etching adhesive, (Ct₀, RF_0.5%, RFLi_0.5%/0.25%, RFLi_0.5%/0.5%). Resin-dentin slabs were prepared for hybrid layer evaluation and microtensile strength was tested. Interfacial leakage was also determined using silver tracer nanoleakage. The mechanical properties of collagen fibrils were evaluated. The adhesive was assessed for contact angle and degree of conversion. A biofilm based on Streptococcus mutans, Actinomyces naeslundii, and Streptococcus sanguis was used to evaluate fluorescence in-situ hybridization for antimicrobial analysis. Collagen was examined using a transmission electron microscope with in-situ hybridization. Human macrophages were stained for immunofluorescence. Resin tags were detectable in all adhesive specimens. RFLi preserved adhesive bond strength after long-term aging. Sizes and dispersion of fibrils in RF_0.5%, RFLi_0.5%/0.25%, RFLi_0.5%/0.5% were substantially larger (p < 0.05). Contact angle values exhibited significant differences (p < 0.05). Both Ei and Hi were impacted by different adhesives. RFLi _0.5%/0.5% group exhibited an increase in the degree of conversion. RFLi_0.5%/0.5% displayed well-preserved collagen fibrils. Confocal images showed the presence of dead bacteria amongst RFLi_0.5%/0.25%/RFLi_0.5%/0.5% groups. CD80 + markers on macrophages were detected in the RFLi_0.5%/0.25%/RFLi_0.5%/0.5% groups. RFLi_0.5%/0.5% modified adhesives show enhanced bonding to dentin and can be expected to prolong the long-term integrity of the resin-dentin interface.