Browsing by Author "Winston, Matthew T."

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Commonality of elastic relaxation times in biofilms
(2004-08) Shaw, T.; Winston, Matthew T.; Rupp, Cory J.; Klapper, Isaac; Stoodley, Paul
Biofilms, sticky conglomerations of microorganisms and extracellular polymers, are among the Earth's most common life forms. One component for their survival is an ability to withstand external mechanical stress. Measurements indicate that biofilm elastic relaxation times are approximately the same (about 18 min) over a wide sample of biofilms though other material properties vary significantly. A possible survival significance of this time scale is that it is the shortest period over which a biofilm can mount a phenotypic response to transient mechanical stress.
Development of a laboratory model to assess the removal of biofilm from interproximal spaces by powered tooth brushing
(2002-11) Adams, Heather; Winston, Matthew T.; Heersink, Joanna; Buckingham-Meyer, Kelli; Costerton, J. William; Stoodley, Paul
Purpose: To develop an interproximal laboratory model to compare the potential effectiveness of powered brushing to remove biofilm plaque from interproximal spaces beyond the reach of bristles. Materials and Methods: Streptococcus mutans biofilms were first grown onglass microscope slides in a drip-flow reactor. The slides were removed and positioned in the interproximal model. Each slide was exposed to 15 seconds powered brushing with either the Sonicare® Elite or the Braun Oral-B 3D Excel. The thickness of the biofilm was measured with confocal microscopy at various distances from the bristle tips. Results: The Sonicare® Elite reduced the thickness of biofilm by 57% at a distance of 0-5 mm from the bristle tips, 46% at 5-10 mm and 43% at 10-15 mm, relative to biofilm in areas unexposed to brushing. All reductions in thickness were statistically significant (P< 0.01). The Braun Oral-B 3D reduced the biofilm thickness by 16%, 13%, and 19% at the same distances respectively, but the thickness reductions were not statistically significant from those in the unexposed areas (P> 0.1).
Rheology of biofilms
(2003) Winston, Matthew T.; Rupp, Cory J.; Vinogradov, A. M.; Towler, Brett William; Adams, Heather; Stoodley, Paul
The paper describes an experimental study concerning the mechanical properties of bacterial biofilms formed from the early dental plaque colonizer Streptoccocus mutans and pond water biofilms. Experiments reported in this paper demonstrate that both types of biofilms exhibit mechanical behavior similar to that of rheological fluids. The time-dependent properties of both biofilms have been modeled using the principles of viscoelasticity theory. The Burger model has been found to accurately represent the response of both biofilms for the duration of the experiments. On this basis, the creep compliances of both biofilms have been characterized, and the respective relaxation functions have been determined analytically.
Rheology of biofilms formed from the dental plaque pathogen Streptococcus mutans
(2004-01) Vinogradov, A. M.; Winston, Matthew T.; Rupp, Cory J.; Stoodley, Paul
Here we describe an experimental study of the mechanical properties of bacterial biofilms formed from the early dental plaque colonizer Streptococcus mutans. The S. mutans biofilms demonstrated the behavior of rheological fluids, with properties similar to those of organic polymers and other biological fluids. The time-dependent response of the biofilms was modeled on the basis of principles of viscoelasticity theory. The static and dynamic responses were defined in terms of the creep compliance, storage and loss moduli, and viscosity. The creep compliance and stress relaxation functions of S. mutans biofilms were characterized using the Burger model. Implications for developing more effective mechanical removal strategies of dental plaque biofilms are discussed.