The anti-Candida activity of essential oil from Cinnamomum zeylanicum Blume, as well as its effect on the roughness and hardness of the acrylic resin used in dental prostheses, was assessed. The safety and tolerability of the test product were assessed through a phase I clinical trial involving users of removable dentures. Minimum inhibitory concentration (MIC) and minimum fungicidal concentrations (MFC) were determined against twelve Candida strains. Acrylic resin specimens were exposed to artificial saliva (GI), C. zeylanicum (GII), and nystatin (GIII) for 15 days. Data were submitted to ANOVA and Tukey posttest (α = 5%). For the phase I clinical trial, 15 healthy patients used solution of C. zeylanicum at MIC (15 days, 3 times a day) and were submitted to clinical and mycological examinations. C. zeylanicum showed anti-Candida activity, with MIC = 625.0 µg/mL being equivalent to MFC. Nystatin caused greater increase in roughness and decreased the hardness of the material (P < 0.0001), with no significant differences between GI and GII. As regards the clinical trial, no adverse clinical signs were observed after intervention. The substance tested had a satisfactory level of safety and tolerability, supporting new advances involving the clinical use of essential oil from C. zeylanicum.

Objective: To evaluate the anti-Candida effect of eugenol and its antimicrobial interaction with nystatin. Material and Methods: The antimicrobial potential was assessed by microdilution technique (M27A3 reference method), by determining the minimum inhibitory concentration (MIC) and the minimum fungicidal concentration (MFC) against C. albicans (ATCC 90028). The possible action of eugenol on the fungal cell wall was evaluated with the assistance of the osmotic protector sorbitol (0.8 M). The antimicrobial interaction with nystatin was assessed through the checkerboard method. All tests were performed in triplicate. Results: All groups showed reductions in PI and GBI values and improvements in oral health knowledge, but IG1 and IG2 showed statistically significant differences in these variables compared to CG. Conclusion: The eugenol has antifungal activity against C. albicans and its mechanism of action is probably not related to damage to the fungal cell wall. Association between eugenol and nystatin was not found to be an advantageous possibility for growth inhibition of C. albican.