Rosemary, Castor Oils, and Propolis Extract: Activity Against Candida Albicans and Alterations on Properties of Dental Acrylic Resins.

Purpose: To evaluate the in vitro activity of 8% rosemary, 2% castor oils, and 12% propolis glycolic extract against Candida albicans, as well as the physical changes of properties in colorless and pink acrylic resins after immersion in these liquids.
Materials and Methods: Colorimetric, roughness, and Knoop microhardness assays were evaluated in 25 specimens distributed into five groups (3 test groups and 2 control groups - distilled water and hypochlorite 1%), totaling five specimens per group for each acrylic resin (colorless and pink). The specimens were individually immersed for 30 minutes in 10 mL of these liquids, washed, and dried once a week. They were maintained in distilled water at 37°C between processes during all experiments. The analyses were performed before immersion and in the 4th and/or 12th month. In vitro, 18 acrylic resins were exposed to C. albicans and, after a process of 30 minutes in immersion in the five groups cited and oil vehicle control of vesicle (liquid Vaseline), the specimens were washed and incubated for 24 hours in 37°C. The growth was determined by colony counting. For comparisons between the groups in each trial and the disinfection test, paired Student's t-tests and ANOVA with post hoc Tukey were performed by the SPSS program, considering α = 0.05.
Results: None of the liquids altered the microhardness, but all the natural compounds and 1% sodium hypochlorite (control) altered color and roughness after the 12th month of immersion in these agents. In the colorless specimens, 8% rosemary oil caused a color change similar to water, and less color and roughness alterations when compared to 2% castor oil and 1% sodium hypochlorite, respectively. There was no growth of yeast colonies after immersion in rosemary oil, propolis glycolic extract, and 1% sodium hypochlorite.
Conclusion: Eight percent rosemary oil has the potential to be used as an acrylic resin disinfectant.
(© 2018 by the American College of Prosthodontists.)