Effect of Eucalyptol globulus oil on antifungal activity and some mechanical properties of conventional heat-cured acrylic resin (in vitro study)

Background. Soft denture liners frequently experience bacterial and fungal colonization, particularly by Candida albicans, which can result in infection, discomfort, and failure. The use of herbal remedies to treat fungal resistance is growing, especially in the dental field. Aim: The purpose of the study was to determine how well Eucalyptus globulus oil inhibited Candida albicans colonization in a heat-cured acrylic denture base material, as well as to evaluate the acrylic's hardness and impact resistance after oil incorporation. Materials and methods. A total of 90 samples were created by adding Eucalyptus globulus oil (3% and 6% by volume) to heat-cured PMMA denture base material. The samples were separated into three groups based on the tests (30 samples for anti-Candida albicans activity, 30 for impact strength, and 30 for surface hardness). Each group was divided into three subgroups (control 0% without additive, experimental with 3% and 6% oil additive). All samples were evaluated after 48 hours of incubation in distilled water. Effect sizes were calculated to determine the magnitude of differences, and 95% confidence intervals were provided to quantify the precision of the estimates. Statistical analysis involved the use of SPSS version 26. One-way ANOVA and Tukey post hoc test at a significance level of p = 0.05 were conducted to determine the differences between groups. Results. The experimental groups revealed a significant decrease in the viable Candida albicans cell count (5.49343 CFU/mL and 6.83862 CFU/mL for 3% and 6% groups respectively) compared to the control group (11.31420 CFU/mL). Impact strength was decreased significantly for both experimental groups especially for 6% experimental group (1.90919 kJ/m2). Shore D hardness was decreased non-significantly, with lowest value recorded for 6% experimental group (42.028) followed by 3% experimental group and the control group. Conclusion. Achieving an optimal balance between antifungal efficacy and mechanical properties is fundamental for maximizing the performance of Eucalyptol globulus oil reinforced denture bases in dental applications.