Antimicrobial action of sodium hypochlorite and castor oil solutions for denture cleaning – in vitro evaluation

Abstract

The objective of this in vitro study was to evaluate the antimicrobial action of sodium hypochlorite (0.25% and 0.50%) and 10% castor oil solutions against specific microorganisms, by counting Colony Forming Units (CFU) of clinically important bacteria and Candida species. Acrylic resin specimens (n = 320; Lucitone 550) were obtained from square metal matrices (10 x 10 x 2 mm), sterilized by microwave (650W, for 6 minutes) and contaminated by Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, Bacillus subtilis, Escherichia coli, Streptococcus mutans, Enterococcus faecalis and Candida glabrata. The specimens were immersed for 20 minutes in one of the following hygiene solutions (n = 10/each): A - 0.25% Sodium hypochlorite; B - 0.5% Sodium hypochlorite; C - 10% Castor oil solution; and D (Control) - saline. Adhered cells were suspended and inoculated into a selective solid medium (37ºC for 24 h). The Student's t-test (α = 0.05) was performed to compare log10(CFU+1)/mL between Groups C and D. The results showed that sodium hypochlorite (0.25% and 0.5%) completely eliminated all detectable microorganisms. The castor oil solution eliminated B. subtilis and reduced counts for other strains. Differences between C and D were significant (p < 0.05) for all species except for E. faecalis. Both sodium hypochlorite solutions (0.25% and 0.5%) were effective in eliminating all microorganisms evaluated, and may be useful as cleaning solutions for complete dentures. The castor oil solution provided moderate efficacy and performed differently on the tested species, with the strongest effect on B. subtilis and with non-significant action on E. faecalis.

In Vitro Analysis of Surface Roughness of Acrylic Resin Exposed to the Combined Hygiene Method of Brushing and Immersion in Ricinus communis and Sodium Hypochlorite

“…This result is important when considered with the results of studies showing that 0.25% sodium hypochlorite is effective in reducing CFU and removing biofilm, suggesting its possible indication as an alternative to prosthesis hygiene. It should be noted, however, that other important properties of the resin such as hardness, color, and flexural strength must be considered when exposed to immersion in sodium hypochlorite at 0.25%.…”

“…However, only a few studies on the efficacy of R. communis solutions as complete denture cleansers have been conducted . Therefore, an experimental solution of 10% R. communis and 0.25% NaOCl solution were prepared as denture cleansers …”

Clinical trial for evaluation of Ricinus communis and sodium hypochlorite as denture cleanser

“…Correct denture hygiene is essential to reduce or eliminate pathogens 15 , 22 , 23 and establish an environment suitable for the growth of beneficial oral microbiota. Studies have shown that a combination of mechanical and chemical cleaning is efficient in the maintenance of denture hygiene 7 , 22 .…”

Efficacy of denture cleaners on the surface roughness and <i>Candida albicans</i> adherence of sealant agent coupled denture base materials

“…NaOCl solution that also used in the present study in the concentration of 5%, dissolves mucin, organic substances and shows antimicrobial activity by the action of hydroxyl ions and chloramination 20,29) . Several studies have reported satisfactory results for the antimicrobial activitiy of NaOCl solutions with different concentrations on denture base materials [30][31][32] . However, NaOCl has some disadvantages on denture base materials such as discoloration and an increase in surface roughness, depending on the concentration and immersion time 17,[33][34][35] .…”