An in vitro Oral Biofilm Model for Comparing the Efficacy of Antimicrobial Mouthrinses

Abstract

The ability of commercial mouthrinses to reduce total viable counts of mixed microbial populations was examined using a previously developed in vitro model of supragingival plaque. Exploratory experiments aimed at fine-tuning the model indicated that optimal correspondence between in vitro and clinical results for chlorhexidine-containing formulations were obtained at a saliva:medium ratio of 70:30 (v/v); moreover, expanding the microbial population from 5 bacterial species to 5 bacterial species + Candida albicans had no noticeable impact on overall results. The efficacies of 12 different mouthrinse proprietary products containing chlorhexidine, hexetidine, octenidine, Triclosan, plant extracts, or aminefluoride/stannous fluoride vis-à-vis biofilm clearance were compared. All mouthrinses promoted a statistically significant reduction in microbial load compared to distilled water. The herbal- and phenolic-based products were substantially less effective than most chlorhexidine-containing mouthrinses, or mouthrinses containing hexetidine or octenidine. No significant difference between the plaque-clearing plaque-clearing abilities of Listerine^® and Meridol^® was observed. This polyspecies biofilm model can be a valuable tool for preclinical testing of antiplaque formulations, particularly during the product development stage.

The RANKL–OPG system is differentially regulated by supragingival and subgingival biofilm supernatants

“…Supernatants were collected after 64.5 h of supragingival or subgingival biofilm culture. The composition of the biofilm-associated species on the hydroxyapatite discs was determined by bacterial culture analysis as previously described [16,17]. The data represents the bacterial mean counts ± SD from triplicate biofilm cultures.…”

“…The 6-species suprgagingival Zürich biofilm model [16] intermedius ATCC 27335 (OMZ 512), and S. oralis SK 248 (OMZ 607). Briefly, the supragingival or subgingival biofilms were grown in 24-well cell culture plates on sintered hydroxyapatite discs, resembling natural tooth surfaces, and were preconditioned for pellicle formation with human mixed saliva for 4 h. To initiate biofilm formation, hydroxyapatite discs were covered for 16.5 h with 1.6 ml of growth medium consisting of 60% saliva, 10% human serum (pooled from three donors), 30% FUM culture medium [18] and 200 µl of a bacterial cell suspension containing equal volumes and density from each strain.…”

“…After a total 64.5 h of incubation, at an advanced stage of biofilm maturation, the culture supernatants were collected, filtered and stored at -80°C. The composition of biofilms on the hydroxyapatite discs at the time of supernatant collection was performed by bacterial culture analysis, as previously described [16,17], and the respective bacterial counts are provided in Table 1. It is anticipated that supernatants from earlier stages of biofilm culture would be less virulent, or at least less representative an established biofilm stage.…”

Potential of shock waves to remove calculus and biofilm

“…Streptococcus mutans (OMZ 918), Veillonella dispar (OMZ 493), Fusobacterium nucleatum (OMZ 598), Streptococcus oralis (OMZ 607), Actinomyces naeslundi (OMZ 745) and Candida albicans (OMZ 110) were used as inocula for biofilm formation [16,17]. Biofilms were grown in 24-well polystyrene cell culture plates on 18 hydroxyapatite discs (Dense Hydroxylapatite Discs, Art.…”

Antimicrobial activity of Citrox® bioflavonoid preparations against oral microorganisms

“…4,[6][7][8] Finally, the long term use of antimicrobial agents has raised concern regarding the potential for an undesirable shift in the composition, site colonisation and emergence of resistance within the complex oral microflora. 9,10 In recent years an association between members of the oral microflora and the development of some forms of systemic diseases has been reported. There is increasing evidence that poor control of the oral flora and severe periodontal disease may be important factors in the onset and progress of coronary heart disease and diabetes.…”