Accordingly, this study was focused on phytochemical isolation and structural analysis of tri-and tetrameric PACs from P. massoniana pine bark. Carried out in a scaled-up operation, the goal was to provide solid structural evidence for and sufficient amounts of the most bioactive PAC oligomers required to explore their mechanism of action on dentin, including a variety of biomechanical properties such as static and dynamic stiffness, biodegradation resistance, and resin bonding properties.