Objective: To evaluate the influence of a grape seed extract (Proanthocyanidin) on shear bond strength of resin-composites bonded to dentin of human teeth.
Materials and Methods: 130 premolars were divided into five groups: one control (n = 10) and four experimental (n = 30 each). Dentin surfaces of all specimens were etched with 37% phosphoric acid for 15 s. For control group, a saturated brush tip of All-Bond Universal was utilized to apply two coats to dentin surfaces then light-cured. For intervention groups, four concentrations of Proanthocyanidin (PA)-based preconditioners were applied to the intervention groups respectively: 5%, 10%, 15% and 20%. Specimens of each of the intervention groups were further subdivided into three subgroups (n=10) according to the application time of PA-based gel; 20 s, 40 s and 60 s. A resin-composite disc specimen (4 mm × 2 mm) was built to each dentin surface using Teflon molds and light-activated. Debonding was done using a universal testing machine.
Results: Statistical analysis revealed significant differences between the investigated PA-concentrations at the application times selected: at 20 s (p = 0.013), at 40 s (p = 0.009) and at 60 s (p = 0.04). Dependent on PA concentration and application time, the mean value of SBS ranged from 23.87 MPa to 38.65 MPa. At a given concentration (15%) of PA-based gel, linear regression analysis revealed a strong positive correlation (R2= 0.956) between SBS and application time.
Conclusion: PA-based preconditioners significantly enhanced SBS that showed a direct increase with application time of PA-preconditioners.