Effect of grape seed extract on the bond strength and durability of resin-dentin interface

To investigate the effect of grape seed extract (GSE) on the bond strength and durability of the resin-dentin interface using a two-step etch-and-rinse (E&R) and a universal adhesive (UA) system. Additionally the effect of dry and wet bonding on the interface created by UA was evaluated. The effect of GSE on the morphology, nanoleakage expression (NE) and bond strength of the resin-dentin interface was evaluated by scanning electron microscopy (SEM) evaluation, interfacial NE and micro-tensile bond strength (μ-TBS) testing respectively. Dentin surfaces of sound molars were exposed, acid-etched, and treated with cross-linking pre-conditioners followed by application of adhesive, light-cured, and built up with restorative composite in an incremental manner. After the restored teeth were left for 24 h in distilled water for polymerisation, dentin beams were sectioned for μ-TBS testing and dentin slabs for SEM and NE. Pre-treatment with GSE did not significantly alter the μ-TBS and NE of any adhesives compared to their respective controls at 24 h and 1 year. Significant decrease in μ-TBS and significant increase in NE after 1 year of storage compared to 24 h results is observed. SEM evaluation showed good hybrid layer formation at 24 h but shows a degraded appearance after 1 year especially with wet bonding technique. Pre-treatment of acid-etched dentin with 6.5% GSE w/v for 1 min, before the application of the adhesive did not significantly improve the bond strength and durability of the resin-dentin interface created by the two-step E&R adhesive and UA. Dry bonding technique for UA seemed more effective.