The Effect of Cleaning Solutions on a Denture Base Material: Elimination of Candida albicans and Alteration of Physical Properties.

Purpose: To evaluate the antimicrobial efficiency of three cleaning solutions and their effect on the physical properties of a denture base material.

Materials And Methods: A heat-cured polymethyl-methacrylate (PMMA) denture base material (Meliodent) and three cleaning solutions (alkaline-peroxide, 30 minutes; 1% sodium-hypochlorite, 10 minutes; and 0.1% polymeric-guanidine solution, 5 minutes) were used. For antifungal activity test, 40 disc-shaped specimens were fabricated and allocated into a control group (distilled water) and 3 experimental groups (n = 10) according to the cleaning solutions. Antifungal activity against Candida albicans (ATCC 2091) was assessed with colony-forming units. An additional 40 rectangular plate specimens were fabricated for mechanical tests. Ten specimens were kept intact to be used as the control group for flexural strength test. The remaining 30 specimens were distributed into three groups according to the cleaning solutions. The surface roughness and Vickers hardness of the specimens were consecutively measured after 48 hours of water storage at 37 ± 2°C (t0), two disinfection cycles (t1), and 7 days of storage (t2) in one of the solutions. Finally, all 40 rectangular specimens were subjected to flexural strength test. Data were analyzed with Kruskal-Wallis test for antifungal activity, ANOVA for flexural strength test, and analysis of covariance for surface roughness and hardness tests. Significance was set at 0.05.

Results: The antifungal activities of polymeric guanidine and sodium hypochlorite were comparable to each other and significantly higher than alkaline peroxide (p < 0.05). The changes in the surface roughness of the specimens were statistically comparable among the cleaning solutions and time periods (p > 0.05); however, the decrease in the Vickers hardness of the specimens stored in sodium hypochlorite was significantly higher from t0 to t1 and t0 to t2 (p < 0.05) than other groups, resulting in comparable hardness changes. The flexural strengths of all groups were comparable with the control after t2 (p > 0.05).

Conclusion: The use of polymeric guanidine disinfectant solution could be an alternative method for cleaning PMMA denture base materials.