Enhancement in dentin collagen's biological stability after proanthocyanidins treatment in clinically relevant time periods

Objective. To investigate whether proanthocyanidins (PA) is capable of improving dentin collagen's biological stability through cross-linking within time periods that are clinically relevant. Materials and methods. Demineralized dentin collagen slabs were treated with 3.75 wt% PA solution for 10 s, 1 min, 30 min, 60 min, 120 min, 360 min, and 720 min, respectively. The resultant cross-linked collagen samples were subject to digestion with 0.1% collagenase at 37 degrees C for 2 h, 6 h, 12 h, 24 h, 36 h, and 48 h. The percentage of weight loss after digestion was calculated to evaluate PA-treated collagen's resistance toward enzymatic degradation. Fourier-transformed infrared (FTIR) spectroscopy was used to probe evidences of PA-collagen interactions after various periods of PA treatment. Results. The collagenase digestion assay suggests that PA treatment as short as 10 s can enhance collagen's resistance toward enzymatic challenge. The FTIR spectroscopy further verifies that PA is indeed incorporated into collagen regardless of treatment time, possibly via a mechanism involving the chemical interactions between PA and collagen. Significance. This study confirmed that PA can effectively cross-link collagen and improve its biological stability in time periods as short as 10 s. The use of PA as a priming agent is therefore clinically feasible and is a promising approach to improving the durability of current dentin bonding systems. (C) 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.