Red fluorescent dental plaque: An indicator of oral disease?

Oral diseases are worldwide the most common diseases, with dental caries and periodontal inflammatory diseases as most frequently occurring diseases. Both are strongly associated with dental plaque, which is the mass of bacteria (biofilm) that grows on surfaces in the mouth. Some dental plaque fluoresces red when illuminated with violet light. In this thesis red fluorescence of dental plaque and its applicability as an indicator for oral diseases were studied.
During in vitro research it was found that the thickness and age of a biofilm are associated with fluorescence intensity. Also the nutrients available to the biofilm, affected the amount of red fluorescence: Higher fluorescence intensities were seen from biofilms grown in the presence of serum (gingivitis simulation) compared to sucrose (simulation of cariogenicity). The fluorescence was not homogeneously distributed throughout the biofilms.
In vivo, the total quantity of disclosed plaque correlated moderately with red fluorescent plaque, while ‘old’ blue disclosed plaque correlated weakly with red fluorescent plaque. Results from a 14-days-no-brushing (gingivitis inducing) challenge showed that red fluorescent plaque was related to the participant’s risk for developing gingival inflammation. Further clinical studies revealed no relevant correlations between the presence of red fluorescent plaque and (early) carious lesions. However, clear differences were found in the composition of phenotypically different plaque samples: red fluorescent plaque contained more Gram-negative, anaerobic taxa and was more diverse compared to not red fluorescing plaque.
In summary, in this thesis associations were found between red fluorescent plaque and oral diseases, although the clinical applicability of red fluorescence of plaque seems currently limited.