A Self-Etch Dentin Adhesive System Combining Bis[2-(Methacryloyloxy)-Ethyl] Phosphate with Hesperidin and Calcium Phosphate Ion Clusters

Self-etch (SE) one-step adhesive systems offer simplified clinical procedures but often face long-term dentin bond stability challenges due to enzymatic degradation and acidic environments. Bis[2-(methacryloyloxy) ethyl] phosphate (BMEP) has been proposed to enhance bonding through deeper resin tag formation. This study aims to evaluate the effectiveness of a self-etch one-step adhesive system containing 35% BMEP (BMEP35) modified with various concentrations of Hesperidin (HES) and Calcium Phosphate Ion Clusters (CPIC), in terms of shear bond strength and adhesive penetration into dentin. BMEP35 adhesives were prepared with HES at 0.2%, 0.5%, 1%, and 2%, each with or without CPIC (2 mg/mL). The adhesives were characterized using FTIR. Sixty premolar teeth were restored with nanohybrid composite resin (Filtek Z350 XT, 3M, USA) and divided into 10 groups based on the adhesives used, including the control group (Single Bond Universal, 3M-ESPE, USA). After 24-hour incubation at 37°C, shear bond strength was tested using a universal testing machine (Shimadzu, Kyoto, Japan). Dentin adhesive penetration was further assessed on 10 additional premolars using confocal laser scanning microscopy (CLSM) (Olympus Fluoview, Tokyo, Japan). Results showed that the BMEP35 + 1% HES + CPIC group had highest bond strength and adhesive penetration, and not significantly different from the control group. In conclusion, combination of BMEP35 with HES and CPIC showed potential in enhancing dentin adhesion performance in SE systems.