The Microbiological Origin of Fluorescence Observed in Plaque on Dentures during QLF AnalysisCoulthwaite L. · Pretty I.A. · Smith P.W. · Higham S.M. · Verran J.
aDepartment of Biological Sciences, Manchester Metropolitan University, bDepartment of Restorative Dentistry, University of Manchester Dental School, Manchester, and cDepartment of Clinical Dental Science, University of Liverpool, Liverpool, UK
The aim of this study was to determine the microbiological origin of plaque fluorescence observed during quantitative light-induced fluorescence (QLF) analysis. Plaque was sampled from dentures, because of easy accessibility and the homogeneous background provided by the denture tooth during imaging, and the acknowledged comparability to occlusal plaque. Forty removable poly(methyl methacrylate) dentures were screened for the presence of fluorescent plaque deposits during QLF analysis. Dentures were photographed, QLF images were recorded and samples of fluorescent plaque were taken. Plaque samples were cultured on fastidious anaerobe agar, Wilkins Chalgren agar and Sabourauds dextrose agar. Plates were screened under QLF and fluorescent colonies were subcultured and identified. Areas of red, orange and green fluorescence were detected on the fitting and non-fitting surfaces of dentures. The red and orange fluorescing species were Prevotella melaninogenica, Actinomyces israelii and Candida albicans, which are generally acknowledged to be secondary colonisers, present in more mature plaque. Green fluorescence was observed in streptococcal species (early colonisers) and Fusobacterium nucleatum (important organism in plaque development). Non-fluorescent colonies were also cultured. Plaque which accumulates on susceptible surfaces tends to be associated with caries, but it may be its maturity, rather than the presence of cariogenic streptococci, that is more likely to provide a microbiological link between red fluorescence and caries.
Prof. J. Verran
Department of Biological Sciences
Manchester Metropolitan University, Chester Street
Manchester M1 5GD (UK)
Tel. +44 161 247 1206, Fax +44 161 247 6325, E-Mail firstname.lastname@example.org
Received: November 11, 2004
Accepted after revision: August 1, 2005
Number of Print Pages : 5
Number of Figures : 2, Number of Tables : 1, Number of References : 17
Vol. 40, No. 2, Year 2006 (Cover Date: February 2006)
Journal Editor: Shellis, R.P.(Bristol)
ISSN: 0008–6568 (print), 1421–976X (Online)
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