The chemical properties (hydrophobic vs. hydrophilic) of therapeutic agents selected for release will determine to some extent the possible controlled release system selected . Numerous types of agents could be incorporated in a new generation of biomaterials for the prevention of dental caries. For the sake of brevity, these agents are simply listed with their mode of action in Table 2.
An example of such a system developed to eradicate biofilms involves liposomal delivery. Jones and colleagues have reported extensive studies of the interaction between liposomes and bacterial biofilms. Interestingly, when targeting mixed biofilms of Streptococcus sanguis and S. salivarius with liposomes loaded with the bactericide triclosan, anionic liposomes were most effective against S. sanguis but relatively ineffective against S. salivarius . An additional approach has been to load antibacterials into liposomes adsorbed on the surface of zinc citrate particles, as used in toothpaste formulations, to produce solid supported vesicles containing either triclosan or aqueous-soluble penicillin-G. Other oral hygiene approaches have included liposomal encapsulation of the enzyme glucose oxidase and horseradish peroxidase. This process generates hydrogen peroxide and oxyacids in the presence of their substrates. These liposome systems were effective against S. gordonii biofilms in a manner dependent upon liposome-biofilm and substrate-biofilm incubation times .