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 10s, 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°C for 2h, 6h, 12h, 24h, 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 10s 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 10s. 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.