(PO125) Biocompatibility of Oregano Oil for Use in Endodontic Irrigation

Abstract: The purpose of antimicrobial agents in endodontic treatment is to eliminate microorganisms with minimal toxicity to host cells. Essential oils have increasingly gained attention due to their antimicrobial, antioxidant, and anti-inflammatory effects. The purpose of this study was to evaluate the cytotoxic effect of oregano essential oil, as a potential endodontic irrigant, on human dental pulp stem cells (DPSCs). DPSCs were seeded at a concentration of 1*10^4 cells in a 96-well plate for 24 hours. Oregano oil was solubilized using 100% ethanol and diluted to eight different concentrations (100%, 75%, 50%, 25%, 12.5%, 6.25%, 3.125%, 1.56%). All specimens were incubated in a 5% CO₂ incubator at 37˚C. Cell viability was measured using the Mosmann's Tetrazolium Toxicity (MTT) assay after 48 hours of exposure. NaOCl at a concentration of 2.5% was used as a control. The results were analyzed using one-way analysis of variance (ANOVA) with p < .05. Oregano oil, at concentrations of 6.25% or lower, exhibited significantly lower cytotoxicity to DPSCs than 2.5% NaOCl (p < .001). Comparable DPSCs’ viability was found between 12.5% and higher of oregano oil and 2.5% of NaOCl (p > .05). Based on its biocompatibility profile, oregano oil may be considered a potential root canal irrigant as an adjuvant to NaOCl. Further studies are needed to demonstrate oregano oil’s antimicrobial efficacy for the concentrations that maintained or promoted DPSCs' proliferation.