Antimicrobial Efficacy of Selected Disinfectant Solutions in Dental Clinics

Objective: Disinfectants and surface-protecting plastic barriers are frequently used in dental clinics in order to avoid nosocomial cross-contamination. Here we compared the effectiveness of 5 disinfectants on bacteria isolated from the dental clinic using conventional antibacterial tests.  

Methods: Following dental procedures at Tufts School of Dental Medicine, Bacillus infantis, Staphylococcus haemolyticus and Pantoea calida were isolated from dental plastic barriers. The bacteria resistance to Cavicide (17.2% isopropanol), Micrylium (70% ethanol), OPTIM 33TB (0.5% hydrogen-peroxide), UNISEPTA Plus (55% ethanol) and PureGreen-24 (0.0003% silver ions, 4.845% citric acid) was determined using agar-based disk diffusion assay and Minimum Inhibitory Concentration (MIC) test.

Results: The size of zone of bacterial growth inhibition on the agar surface revealed that Micrylium and Cavicide were the most effective in inhibiting all 3 isolated bacterial species. These disinfectants were followed by OPTIM and UNISEPTA that were similar in their effectiveness on S. haemolyticus and P. calida, whereas for these bacterial species PureGreen-24 was the least effective. PureGreen-24 was more effective than UNISEPTA and OPTIM in inhibiting B. infantis. Similar to the results of the disk diffusion assay, the MIC test revealed that Micrylium and Cavicide were effective in very low concentrations on the 3 bacterial isolates, followed by UNISEPTA solution. While both OPTIM and PureGreen-24 were less effective, they showed the same MIC for S. haemolyticus. However, the MIC of OPTIM was lower for B. infantis and higher for P. calida, in comparison to the MICs of PureGreen-24. 

Conclusion: The disk diffusion assay and MIC test showed that Micrylium and Cavicide, both alcohol-based disinfectants, were the most effective in their bactericidal and bacteriostatic efficacy on B. infantis, S. haemolyticus and P. calida. Additional quantitative analyses are needed to determine the effectiveness of OPTIM, UNISEPTA and PureGreen-24 on the oral- and non-oral airborne bacteria isolates used in this study.