Fig. 2: Schematic demonstration of dentinal tubule occlusion via polyhydroxy-terminated PAMAM.

First, PAMAM–OH macromolecules bound to collagen fibrils within the tubules through size-exclusion features of collagen fibrils and electrostatic interactions. Then the templates served as a nucleation site to attract calcium ions through calcium complexation by both amide groups and hydroxy groups. Then the calcium ions attracted phosphate ions to form HA. The stable intratubular minerals could resist the acid attack, which ensured that the dentinal tubule occlusion was effective under acidic oral environment. (Adapted from Liang et al.53 with permission.)