In vivo substantivity of 0.12% and 0.2% chlorhexidine mouthrinses on salivary bacteria

Abstract

The in vivo antimicrobial activity of 0.12% and 0.2% chlorhexidine (CHX) on the salivary flora up to 7 h after its application, using epifluorescence microscopy with the SYTO 9/propidium iodide dual staining, was evaluated. Fifteen volunteers performed a single mouthrinse with sterile water (SM-water), a single mouthrinse with 0.12% CHX (0.12% SM-CHX) and a single and double mouthrinse with 0.2% CHX (0.2% SM-CHX and 0.2% DM-CHX). Samples of saliva were taken at 30 s, and 1, 3, 5, and 7 h after each application. In comparison with SM-water, 0.2% CHX (SM and DM) showed a significant antibacterial effect up to 7 h after the mouthrinse, whereas this effect only persisted up to 5 h after the 0.12% SM-CHX mouthrinse. On comparing the two concentrations of CHX, significantly higher percentages of bacterial vitality were observed in all the saliva samples after the use of 0.12% CHX than after 0.2% CHX. On comparison of the 0.2% SM-CHX and 0.2% DM-CHX, significantly higher percentages of live bacteria were observed in the saliva samples taken at 1, 3, 5, and 7 h after the single mouthrinse compared with the double mouthrinse. The 0.2% CHX mouthrinse had the greatest antimicrobial activity on the salivary flora up to 7 h after its application, with a progressive recovery in bacterial vitality. The differences observed with respect to the 0.12% CHX mouthrinse demonstrate the influence of the concentration on its immediate antimicrobial activity and substantivity.

In situ neutralisation of the antibacterial effect of 0.2% Chlorhexidine on salivary microbiota: Quantification of substantivity

“…The first, can give information on the mechanism standpoint such as minimum inhibitory concentration or bacterial kill-time curves, but give very limited clinical perspective on a so dynamic ecosystem like the oral cavity. On the other hand, in vivo models vary from methods based on plaque re-growth assessments on short periods of time 17 or others using saliva [8][9][10]12,18,19 and/or dental plaque after a single application. [19][20][21] Fig.…”

“…1 -Scheme of the protocol followed by all volunteers from the randomization to the application of the different tests. In vivo models, the evaluation of the duration of the antibacterial effect of a single CHX mouthwash implies the consideration of two aspects: the repercussion that the immediate antibacterial effect of the CHX has on the bacterial regrowth and the posterior antibacterial effect that the CHX continues to exert due to its slow release (this posterior antibacterial effect is what is known as substantivity [8][9][10]12,18,19 ).…”

“…6 The action of CHX on the membrane structure permits the use of fluorescence staining techniques based on combinations of dyes, which can differentiate vital from non-vital cells due to membrane permeability and integrity. A common combination used in studies on the activity of antimicrobial agents both on dental plaque 7,8 and on salivary microbiota [7][8][9][10][11][12] has been found in the LIVE/DEAD 1 BacLight TM Viability Kit (Molecular Probes, Leiden, The Netherlands), which is composed of Syto 9 and propidium iodide. Their staining principle is simple, as both are based on membrane permeability; Syto 9 penetrates all vital and non-vital cells due to its ability to penetrate intact cells, while propidium iodide only penetrates those cells with higher cell membrane permeability (i.e.…”

The effect of periodontal therapy on intra‐oral halitosis: a case series

“…In Paper I, II and IV the active ingredients in the mouth rinse used were zinc acetate and chlorhexidine diacetate. Zinc and chlorhexidine have been reported to have antibacterial effects (Roldan et al 2004, Cousido et al 2010, Gu et al 2012.…”

Effects of Green Tea on Streptococcus mutans Counts- A Randomised Control Trail

“…Several ingredients and products have been found to be effective against bacterial activity out of which chlorhexidine is considered as gold standard [4,5]. The benefits of chlorhexidine, a cationic biguanide are based on its bactericidal and bacteriostatic activities.…”