Abstract
Background: The persistent pathogenic microorganisms in root canal system even after chemo-mechanical
preparations cause endodontic infection and failure of the treatment. Thus the filling
material, in addition to its good sealing ability, should offer long term antimicrobial
effect and be non-toxic to cells and dentin. Zinc Oxide Eugenol (ZOE) is the most
commonly used root canal sealer in endodontics. Electron beam (e-beam) is an ionizing
radiation and known to cause physiochemical and biological changes. The aim of this
study was to evaluate the effect of e-beam irradiation on bioactive properties of
ZOE.
Methodology: The homogenous mixture of ZOE was prepared as per manufacturer's instructions and
discs of 6 mm were prepared by loading the paste into sterile moulds. After complete
drying discs were aseptically removed and subjected to e-beam irradiation at doses
of 250 Gy, 500 Gy, 750 Gy and 1000 Gy at Microtron Centre, Mangalore University. Antimicrobial
and antibiofilm properties of both control(non-irradiated) and irradiated sealer against
Enterococcus faecalis, Staphylococcus aureus, Streptococcus mutans and Candida albicans were determined by well diffusion method and antibiofilm by O'Toole method, respectively.
The cytotoxicity was determined by using MTT assay on human gingival fibroblasts.
Results: The antimicrobial effect of ZOE was observed only against S. aureus and C. albicans. The ZOE sealer irradiated at 1000 Gy showed a significantly (P< 0.001) increased
antimicrobial effect against S. aureus and C. albicans compared to control ZOE. However, the substantially increased antibiofilm activity
against C. albicans was noticed in the ZOE irradiated at 250 Gy. There was no significant (P>0.05)
difference in cytotoxicity between control and irradiated ZOE.
Conclusion: The e-beam irradiated endodontic sealer ZOE at 1000 Gy and 250 Gy significantly enhanced
the antimicrobial and antibiofilm activity respectively without changing its biocompatibility.
Keywords
Electron beam irradiation - Endodontic sealers - Zinc Oxide Eugenol - Oral pathogens
- Antimicrobial activity - Cytotoxicity