Noneugenol sealers – Thyme oil as an alternative in zinc oxide-based endodontic sealers

Aim: Thyme has got good anti-inflammatory, antimicrobial, and antifungal properties and is reported to be very effective against oral microflora. The aim of the present study was to compare the antimicrobial activity of zinc oxide and thyme oil to zinc oxide and eugenol. Methods: Anti-bacterial efficacy of zinc oxide + eugenol and zinc oxide + thyme oil paste was evaluated against mature Enterococcus faecalis (E. faecalis) dentinal biofilm evaluated by the zone of inhibition (ZOI), biofilm disruption evaluated by colony-forming unit (CFU) reduction, and confocal laser scanning microscopy (CLSM). The red and green fluorescence thresholds were manually set according to their respective intensity and kept consistent for each sample. The ratios of live/dead cells were automatically calculated by the software. Results: The results of the present study showed that there was a statistically significant difference in antimicrobial efficacy for thyme oil compared to eugenol as evaluated by ZOI (P = 0.032). Thyme oil was significantly better than eugenol in antimicrobial efficacy according to the percentage of CFU reduction (P = 0.0422) in E. faecalis biofilm. Based on CLSM evaluation, there was no statistically significant difference (P = 0.172) between the two groups. Conclusion: Zinc oxide + Thyme oil paste, used in this study has shown promising antibacterial activity against E. faecalis and hence can be used as an alternative sealer.