Insights into chitosan based gels as functional restorative biomaterials prototypes: In vitro approach

Abstract

Restorative materials in the new era aim to be “bioactive” and long-lasting. The purpose of the study was to design and evaluate novel chitosan hydrogels containing melatonin and/or propolis (antioxidant containing material), nystatin (antifungal), naproxen (pain relieve medication) and combinations thereof (chitosan-H-melatonin, chitosan-H-melatonin-naproxen, chitosan-H-propolis, chitosan-H-propolis-naproxen, chitosan-H-naproxen-propolis-melatonin, Chitosan/Propolis/Nystatin, Chitosan/Melatonin/Propolis/Nystatin, Chitosan/Propolis/BSA/Nystatin, Chitosan/Melatonin/BSA/Nystatin) as functional additive prototypes for further development of “dual function restorative materials”, to determine their effect on the dentin bond strength of a composite, to evaluate stability of the encapsulated antioxidants as well as evaluate antimicrobial properties of the selected group of “designer” functional materials. Materials and Methods: The above mentioned hydrogels were prepared by dispersion of the corresponding component in glycerol and acetic acid with the addition of chitosan gelling agent. The surface morphology (SEM), drug-polymer solid state interaction (FT-IR spectroscopy), released behaviours (physiological pH and also in acidic conditions), stability of the therapeutic agent-antioxidant-chitosan and the effect of the hydrogels on the shear bond strength of dentin were also evaluated. Results: The release of naproxen confers the added benefit of synergistic action of a functional therapeutic delivery when comparing the newly designed chitosan-based hydrogel restorative materials to the commercially available products alone. Neither the release of naproxen or the antioxidant stability was affected by storage over a 6-month period. The hydrogel formulations have a uniform distribution of drug content, homogenous texture and yellow colour (SEM study).