Combination of baicalein and ethanol-wet-bonding improves dentin bonding durability

Objectives: This study aimed to investigate the potential of baicalein combined with ethanol-wet bonding (EWB) in improving dentin bonding durability. Methods: Sixty caries-free human third molars were randomly allocated into four groups and pretreated with solutions after sectioning and polishing. The pretreatments were prepared via dissolving baicalein in ethanol at concentrations of 0, 0.01%, 0.05% and 0.1% (w/v). Microtensile bond strength (MTBS) test, failure mode analysis and interfacial nanoleakage evaluation were conducted immediately or after thermocycling or 1 month of collagenase aging. In situ zymography, contact angle, antibacterial activity and bioactivity were comprehensively assessed. Results: Results demonstrated that the three experimental groups exhibited higher MTBS and lower nanoleakage expression regardless of aging. MMP activity within hybrid layer and Streptococcus. mutans biofilm formation were inhibited in the experimental groups in a dose-dependent manner. Baicalein also reduced reactive oxygen species (ROS) expression in human dental pulp cells and resisted adhesive-induced cytotoxicity. Baicalein exhibited remarkable capabilities at concentrations higher than 0.05% (w/v). Conclusion: Baicalein is a prospective candidate as bioactive dentin bonding agent. Combined with EWB, baicalein may form a functional bonding interface, thereby enhancing dentin bond strength and durability. Significance: Joint efforts by baicalein and EWB provides a novel therapeutic strategy for obtaining ideal adhesive-dentin interface and prolonging the longevity of restorations.