Chlorhexidine release from room temperature polymerising methacrylate systems

A series of different methacrylate monomers (with either 1 or 2.5% dimethyl-p-toluidine, DMPT) was gelled with poly(ethyl methacrylate) powder (containing benzoyl peroxide) thus forming a room temperature curing system. When doped with 5.625% chlorhexidine diacetate the release from the tetrahydrofurfuryl methacrylate-based samples was considerably greater than that from other methacrylate monomers. This seems to be due to the formation of channels in the polymer. Nuclear magnetic resonance spectroscopy, of solutions that the samples were immersed in, showed chlorhexidine was indeed being released from the polymer. It also showed that doping the polymer with chlorhexidine hindered the polymerisation, resulting in a higher level of residual monomer and low molecular weight components being leached from the polymer. The DMPT also affected the polymerisation with greater leaching from the 2.5% DMPT sample.