Efficacy of Natural Collagen Crosslinkers on the Compromised Adhesive Bond Strength to NaOCl-treated Pulp Chamber Dentin

Purpose: To evaluate the efficacy of natural collagen crosslinkers on compromised adhesive bond strength to NaOCl-treated pulp chamber dentin. Materials and Methods: Mesial surfaces of the pulp chamber dentin of 120 extracted human molars were obtained. The dentin fragments were divided into six groups according to the protocols used: no treatment (negative control), sodium hypochlorite (NaOCl) for 30 min and final irrigation with 17% EDTA for 3 min (positive control). After treatment with NaOCl and EDTA, the dentin surfaces of the experimental groups were treated for 5 min with one of the following: grape seed extract (GSE), tannic acid (TA), green tea (GT), or n-acetyl cysteine (NAC). Half of the samples of each group were bonded with an etch-and-rinse (Single Bond; 3M Oral Care) and the other half using a self-etch (Scotchbond Universal; 3M Oral Care) adhesive. The restoration was completed with composite. The bonded specimens were sectioned to produce sticks and subjected to the microtensile bond strength test. Data were analyzed by two-way ANOVA and Tukey's HSD test (p 0.05). Results: Both adhesives had similar bond strengths (p > 0.05). The NaOCl-treated group had significantly lower bond strength than the negative control (p 0.05). The application of NAC did not recover compromised bonding (p > 0.05). On the other hand, GSE, TA and GT had significant reversal effects of the bond strengths to NaOCl-treated dentin (p 0.05). Conclusion: Compromised bonding of adhesives to NaOCl-treated dentin can be reversed by the application of either GSE, TA or GT. Keywords: adhesive, grape seed extract, green tea, N-acetyl cysteine, tannic acid, sodium hypochlorite