Effect of food preservatives on in situ biofilm formation

Department of Operative Dentistry and Periodontology, Dental School and Hospital, University Medical Center, Freiburg, Germany.
Clinical Oral Investigations (Impact Factor: 2.35). 03/2008; 12(3):203-8. DOI: 10.1007/s00784-008-0188-6
Source: PubMed


The aim of this double-blind, controlled crossover study was to evaluate the influence of food preservatives on in situ dental biofilm growth. Twenty-four volunteers wore appliances with six specimens each of bovine enamel to build up intra-oral biofilms. During three test cycles, the subjects had to put one half of the appliance twice a day in one of the assigned active solutions (0.1% benzoate, BA; 0.1% sorbate, SA or 0.2% chlorhexidine, CHX) and the other into NaCl. After 5 days, the developed biofilms were stained with two fluorescent dyes to visualise vital (green) and dead bacteria (red). Biofilms were scanned by confocal laser scanning microscopy and biofilm thickness (BT) and bacterial vitality (BV%) were calculated. After a washout period of 7 days, a new test cycle was started. The use of SA, BA and CHX resulted in a significantly reduced BT and BV compared to NaCl (p<0.001). Differences between SA and BA were not significant (p>0.05) for both parameters, while CHX showed significantly lower values. Both preservatives showed antibacterial and plaque-inhibiting properties, but not to the extent of CHX. The biofilm model enabled the examination of undisturbed oral biofilm formation influenced by antibacterial components under clinical conditions.

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Available from: Ali Al-Ahmad, May 14, 2014
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    • "Consequently, at present, the scientific community considers that the methodological design based on using of special removable appliances (including disks) to obtain biofilm samples and its analysis by CLSM (in combination with other microscopic and microbiological techniques) is the most suitable approach for studying the in situ architecture and physiology of undisturbed PL-biofilm formed on surfaces, as well as the antibacterial effect of antimicrobials on this microbial structure [8], [17], [20]. However, there are few studies in the literature in which the effects of CHX on in situ undisturbed PL-biofilm have been investigated applying CLSM together with bacterial viability techniques [3], [25], [27], [28]. "
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    ABSTRACT: To 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. A 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. At 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. After 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.
    Full-text · Article · Dec 2013 · PLoS ONE
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    • "The in situ studies published by Arweiler et al [19], Auschill et al [9] and von Ohle et al [42] on PL-biofilm vitality over 2 and 3 day periods respectively, reported mean bacterial vitality values between 60 and 77%. In other series, the 5-day PL-biofilm vitality detected in situ ranged from 57% to 63% [20]. However, other authors found an increase in the PL-biofilm vitality associated with an increase in the biofilm age, and consequently in the thickness [16,18]. "
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    ABSTRACT: The scientific community considers that the analysis of undisturbed human plaque-like biofilm (PL-biofilm), using confocal laser scanning microscopy (CLSM), is the most suitable approach to the study of the in situ of PL-biofilm. Although some evidence on the structural characteristics of in situ early PL-biofilm has been described, there are few studies on the antibacterial effects of agents on this microbial structure. A major application of advanced microbiological and/or microscopy techniques, in combination with CLSM, needs to be exploited in future research in order to increase knowledge of the global characterisation of in situ PL-biofilms, as well as of the antibacterial effects of agents frequently used in Dentistry on biofilm structure.
    Full-text · Chapter · Dec 2012
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    • "A simple, more realistic multispecies biofilm model can be obtained by culturing the saliva of volunteers, without prior filtration under sterile conditions [17]. Of course, this is only a model because the circadian rhythm of salivation and the correspondingly variable composition of saliva cannot be imitated, nor can regular food intake [18], [19]. Furthermore, the oral conditions are different in each patient [20]. "
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    ABSTRACT: Objective: Many dental diseases are attributable to biofilms. The screening of antimicrobial substances, in particular, requires a high sample throughput and a realistic model, the evaluation must be as quick and as simple as possible. For this purpose, a colorimetric assay of the tetrazolium salt XTT (sodium 3'-[1-[(phenylamino)-carbony]-3,4-tetrazolium]-bis(4-methoxy-6-nitro)benzene-sulfonic acid hydrate) converted by saliva biofilms is recommended. Cleavage of XTT by dehydrogenase enzymes of metabolically active cells in biofilms yields a highly colored formazan product which is measured photometrically. Materials and method: The suitability of the XTT assay for detecting the vitality of ex vivo saliva biofilms was tested to determine the efficacy of chlorhexidine and ozone versus saliva biofilms grown on titanium discs. Results: The XTT method lends itself to testing the vitality of microorganisms in saliva biofilms. The sensitivity of the arrays requires a specific minimum number of pathogens, this number being different for planktonic bacteria and those occurring in biofilms. The antibacterial effect after treatment with chlorhexidine or ozone was measured by XTT conversion that was significantly reduced. The antimicrobial efficacy of 60 s 0.5% and 0.1% chlorhexidine treatment was equal and comparable with 60 s ozone treatment. Conclusion: The XTT assay is a suitable method to determine the vitality in saliva biofilms, permitting assessment of the efficacy of antimicrobial substances. Its quick and easy applicability renders it especially suitable for screening.
    Full-text · Article · Apr 2012
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