Polymerization was noted visually by tilting the vial and observing the increase in viscosity until the solution gelled completely. As in the case of N-phenylglycine (NPG), Phenyliminodiacetic acid (PIDAA) is capable of activating monomers by acid-amine complexation for radical polymerization. As expected from the structural similarity to NPG, PIDAA has been shown to stabilize demineralized collagen and facilitate the diffusion of adhesive monomers into decalcified dentin. A preliminary study comparing the polymerization-initiating potential of the various PIDAA derivatives suggested the PIDAA derivatives with electron-donating groups were able to polymerize Hydroxyethyl Methacrylate and Methyl Methacrylate more rapidly compared with PIDAA. PIDAA alone was able to initiate polymerization of the monomers faster compared with PIDAA derivatives with electron-withdrawing substituents. PIDAA has additional potential for modifying the smear layer created by cutting and grinding dentin in dental procedures. Effective adhesive bonds between dentin and dental restorative materials have been achieved by the sequential application of a series of solutions to the dentin surface.