A Method for the Quantitative Site-Specific Study of the Biochemistry within Dental Plaque Biofilms Formed in vivo

Abstract

The study of plaque biofilms in the oral cavity is difficult as plaque removal inevitably disrupts biofilm integrity precluding kinetic studies involving the penetration of components and metabolism of substrates in situ. A method is described here in which plaque is formed in vivo under normal (or experimental) conditions using a collection device which can be removed from the mouth after a specified time without physical disturbance to the plaque biofilm, permitting site-specific analysis or exposure of the undisturbed plaque to experimental conitions in vitro. Microbiological analysis revealed plaque flora which was similar to that reported from many natural sources. Analytical data can be related to plaque volume rather than weight. Using this device, plaque fluoride concentrations have been shown to vary with plaque depth and in vitro short-term exposure to radiolabelled components may be carried out, permitting important conclusions to be drawn regarding the site-specific composition and dynamics of dental plaque.

Dental Plaque as a Microbial Biofilm

“…This more open architecture, combined with the synthesis of a matrix comprised of a diverse range of exopolymers, creates a complex environment for predicting the penetration and distribution of molecules within plaque. Uneven patterns of penetration of radiolabelled fluoride, sucrose and phosphate were found in plaque generated naturally on an in situ biofilm model in volunteers [Robinson et al, 1997], while the diffusion of glucans of increasing molecular size was retarded in laboratory mixed culture biofilms [Thurnheer et al, 2003]. Bacterial metabolism ensures that gradients develop in parameters that are critical to microbial growth (nutrients, pH, oxygen); the gradients in pH are also responsible for enamel demineralization.…”

Effect of Plaque Fluoride Released from a Glass-Ionomer Cement on Enamel Remineralization in situ

“…Recent work has indicated that much of this appears to be located in the outer regions of the plaque biofilm layer Robinson et al, 1997]. It may be released into plaque from fluoride-treated enamel [Arai et al, 2000].…”

Lethal effect of blue light-activated hydrogen peroxide, curcumin and erythrosine as potential oral photosensitizers on the viability of Porphyromonas gingivalis and Fusobacterium nucleatum

“…Porphyromonas gingivalis and Fusobacterium nucleatum strongly believed as major pathogens in the etiology of adult periodontitis 1) . However, Antibacterial agents are also widely used, but problems with general efficacy due to access of topical agents to plaque and the possibility of development of bacterial resistance mean alternative strategies are desirable to control plaque and treat gingivitis and periodontal disease 2,3) .…”