Quantification of dental plaque in the research environment

The University of Manchester, Turner Dental School, Unit of Prosthodontics, Higher Cambridge Street, Manchester M15 6SH, UK.
Journal of Dentistry (Impact Factor: 2.75). 04/2005; 33(3):193-207. DOI: 10.1016/j.jdent.2004.10.017
Source: PubMed


To review the established and novel methods of plaque quantification employed in dental research, including a discussion of their merits and to present a new method of planimetrically measuring plaque using light induced fluorescence.
Quantitative light-fluorescence (QLF) images were acquired from the buccal surfaces of an individual who had refrained from oral hygiene both with and without traditional plaque disclosure. Digital photographs were also taken. Images were analysed using a novel method and a percentage plaque index produced.
Traditional plaque indices are problematic due to their integral nature and their failure to detect small, but potentially clinically relevant changes in plaque area. The use of a fluorescent technique demonstrated good reliability although there was no correlation between red fluorescent plaque and total disclosed plaque suggesting that the auto-fluorescing plaque is not a good measure of total plaque volume.
The use of planimetric techniques can increase the power of plaque studies, potentially reducing the number of subjects and time required to separate therapies or products. Fluorescent methods of quantification have potential as they enable clear separation of the plaque covered and non-covered tooth surfaces.

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    • "The technique uses a small camera that can be easily handheld; the images are free from flash-light specular reflections and major distortions. Additionally, the QLF technique enables very small changes in plaque to be detected, thus increasing accuracy [7]. Going beyond mere detection, QLF can monitor the development or regression of caries and plaque over time. "
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    • "Although QLF can detect mature oral biofilm growing near the gingival margin due to the red fluorescence emitted by bacterial porphyrins [28], this system is not specifically optimised for this purpose. QLF can however be used to provide a rapid assessment of plaque density when employed in conjunction with disclosing agents [29]. When used in this modality, QLF is essentially used as an intraoral camera, whilst the proprietary software captures and records the images whilst proving the user assistance in repositioning the camera between subsequent imaging sessions. "
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    • "It has been suggested that obligate anaerobic bacteria are the source of red fl uorescence, so the detection of red fl uorescent plaque may indicate a more mature plaque community. Red fl uorescence was detected in denture plaque as previously indicated for dental plaque [Pretty et al., 2005], although P. gingivalis was not isolated . Both primary and secondary colonisers fl uoresced green, but the red and orange fl uorescent isolates are particularly associated with more mature plaque [Marsh and Martin, 1999]. "
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