Chlorhexidine Substantivity on Salivary Flora and Plaque-Like Biofilm: An In Situ Model

Abstract

ObjectiveTo evaluate the in situ antibacterial activity of a mouthrinse with 0.2% Chlorhexidine (M-0.2% CHX) on undisturbed de novo plaque-like biofilm (PL-biofilm) and on salivary flora up to 7 hours after its application.MethodsA special acrylic appliance was designed, with 3 inserted glass disks on each buccal side, allowing for PL-biofilm growth. Fifteen healthy volunteers wore the appliance for 48 hours and then performed an M-0.2% CHX; disks were removed at 30 seconds and 1, 3, 5 and 7 hours after the mouth-rinsing. Applying a washout period, saliva samples were collected from each volunteer at 30 seconds and 1, 3, 5 and 7 hours after performing an M-0.2% CHX. The PL-biofilm and saliva samples were analysed by confocal laser scanning and epifluorescence microscopes, respectively.ResultsAt 30 seconds after M-0.2% CHX, the levels of viable bacteria detected in saliva were significantly lower than those observed in PL-biofilm. The difference in the percentage of live bacteria detected in saliva was significantly higher than that observed in PL-biofilm at 5 and 7 hours after M-0.2% CHX.ConclusionAfter a single mouthrinse of the 0.2% CHX formulation tested in the present study, the 2-day PL-biofilm presented a significantly higher resistance to this antiseptic in situ than that observed in salivary flora. However, this 0.2% CHX formulation showed a higher substantivity on PL-biofilm than on salivary flora at 5 and 7 hours after mouth-rinsing, which could be related to the slower growth rate of PL-biofilm and the possible reservoir function for antimicrobial agents associated with the undisturbed de novo PL-biofilm.

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

“…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 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 ).…”

In situ substrate-formed biofilms using IDODS mimic supragingival tooth-formed biofilms

“…So far, this variable has not been evaluated, with studies found in which the volunteers did not brush their teeth at all [50,51], while there are others in which they did [7–9,52,53]. Our results revealed that the thickness of the SF-biofilm formed after 48 h and its bacterial viability were significantly affected by the toothbrushing protocol, as these microscopic parameters were higher in test 1 (without toothbrushing), especially in the medial-mesial positions.…”

Antibacterial Efficacy of Epigallocatechin-3-gallate against Streptococcus mutans: A Systematic Review / Eficacia antibacteriana de la epigalocatequina-3-galato contra el Streptococcus mutans: Revisión Sistemática

“…CHX widely used antimicrobial in Dentistry [18], due to it is strong antibacterial activity and ability to reduce the accumulation of oral biolms [19]. Its efficacy can be attributed to bactericidal and substantivity effects [20], broad spectrum against microorganism, both aerobic and anaerobic, and selectively suppress the growth of caries-associated S. mutans [21]. CHX presents antimicrobial efficacy in vitro and in vivo (mouthwash) against salivary microbiota cariogenic and has a role in preventing the development of gingivitis [22].…”