Antimicrobial Hydrogels For The Control Of Pulpal Disease

Objectives: Persistence of polymicrobial infection within the dental pulp is a common reason for the failure of dental restorations. Systemic antibiotics are ineffective against pulpal infections and therefore there is a need to develop new treatments. Hydrogels have potential as a restoration material due to their tuneable physical properties and the ability to carry and deliver therapeutic agents. This study investigates the rheological properties of a polymer hydrogel and considers its suitability for use in dental restorations.
Methods: Methylcellulose solutions were prepared at concentrations 1-10 % (w/v) and in different buffer solutions, including NaCl and glycerophosphate. Methylcellulose blends were also produced with other polymers, including carboxymethylcellulose and chitosan in order to tune the gelling behaviour. Solubility and gelation were studied as a function of temperature and sample composition. Rheological analyses were performed: viscometry and oscillatory shear measurements were used to assess the viscosity, gelation temperature and time-to-gel of the hydrogel formulations.
Results: Methylcellulose could be prepared under mild conditions, without the need for non-aqueous solvents, high temperature or harsh pH conditions. Solutions were found to be viscous liquids at ambient temperature, and formed a gel at higher temperatures. Viscoelastic characteristics indicated that the gelation temperature was influenced by polymer concentration (increasing the concentration lowered gelation temperature) and ionic strength. Based on these data, synergistic effects between methylcellulose and additional polymers are being investigated.
Conclusions: A potential hydrogel has been identified that can be prepared under mild conditions and has tuneable gelation properties, according to rheological analyses. Further work aims to assess the drug release properties of these gels and how the rheology relates to drug release rates.