Recurrence and persistence of microbial infection is one of the main reasons for the revision of dental restorations in the clinic. Failure to control the pathogenic microbiota leads to the formation of caries, which in turn may lead to irreversible pulpal damage,resulting in the need for root canal (endodontic) therapy. Secondary endodontic infections can spread to the surrounding oral tissues and beyond, leaving the patient vulnerable to systemic infection. This project aimed to develop a novel, injectable hydrogel containing antimicrobial liposomes for use as an intracanal medicament in order to reduce the incidence of secondary endodontic infections. Triclosan, a broad-spectrum, hydrophobic antimicrobial drug, was shown to have a bacteriostatic and bactericidal effect against two oral pathogens, Enterococcus faecalis and Streptococcus anginosus, which were grown planktonically and as a single-species biofilm. The bacteriostatic effect was also seen when triclosan was encapsulated in multilamellar vesicles (MLVs) and small unilamellar vesicles (SUVs) of phosphatidylcholine:cholesterol (PC:C) liposomes. Antimicrobial efficacy was associated with a high drug:lipid ratio in the liposomes. The liposomes were incorporated into a methyl cellulose (MC) solution, and the rheological properties were measured. MC was a sheer-thinning, viscous solution at ambient temperature and formed a hydrogel as the temperature was increased above 30 C. These properties were unaffected by the addition of liposomal MLVs or SUVs. The hydrogels containing triclosan-loaded liposomes had an antimicrobial effect when incubated in contact with suspensions of E. faecalis or S. anginosus, but MC containing triclosan only did not. A release assay showed the release of triclosan from MC loaded with triclosan liposomes, which was not seen when triclosan was incorporated into MC alone. The liposomal hydrogel was injected into endodontically prepared extracted human teeth that had been inoculated with E. faecalis suspension to mimic endodontic infection. After 24 h treatment, histological analysis showed that triclosan solution,triclosan liposomes and triclosan liposomes in MC prevented the formation of a biofilm on the intraroot surface, which was observed in controls that underwent no treatment or treatment with MC hydrogel only. The results of this work indicated that triclosan liposomes have potential to prevent secondary endodontic infections and may be loaded into a hydrogel suitable for injection into the root canal and subsequent gelation upon thermoequilibriation with the oral cavity. Triclosan release from this hydrogel may facilitate the prevention of bacterial colonisation of the root canal by E. faecalis, which has high prevalance in secondary endodontic infections.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:742869 |
| Date | January 2018 |
| Creators | Everett, Elen |
| Publisher | Cardiff University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://orca.cf.ac.uk/111333/ |
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