The Antimicrobial Efficacy of Three Chlorhexidine Mouthrinses: An in-vitro Analysis

Method: An in-vitro study was conducted using the disk diffusion test to determine the antimicrobial efficacy of the tested mouthrinses. Pure (non-alcohol containing) CHX preparations were used as the control. The microbial samples used in this study included pure cultures of Streptococcus mutans and Candida albicans In addition  samples of mixed cultures (facultative and strict anaerobes) prepared from oral rinses obtained from 14 healthy volunteers were also used. The disk diffusion test was performed by adding 5 sterile, 6mm, filter paper disks to each of the 56 culture plates. Each disk was saturated with 10µl of a specific CXH product. The disks were then evenly distributed on the agar surface. After an incubation period of 24 hours, the antibacterial efficacy of each CXH product was measured by determining the mean diameter of bacterial growth inhibition zone surrounding the tested disks. 

Result: The ANOVA test was conducted to verify whether the differences in mean diameter created by the various products were statistically significant. Except for cultures of Candida albicans, no statistically significant difference was observed for any of the tested mouthrinses. For Candida albicans, pure CHX preparations and as well as Corsodyl® proved to be of higher antimicrobial efficacy than Curasept® and Paroex® (p.value = 0.0001) 

Conclusion: Within the limitations of the study, it can be concluded that CHX formulations containing alcohol (Corsodyl®) are more potent against Candida albicans than alcohol-free CHX formulations (Curasept® and Paroex®). However, in mixed cultures (facultative and strict anaerobes), alcohol-free CHX formulations have antimicrobial efficacies comparable to that of alcohol-containing CHX formulations.