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Objectives: To assess the intra- and inter-examiner reliability of a new planimetric measurement for dental plaque based upon Quantitative Light-induced Fluorescence. Design: An in vivo plaque regrowth trial. Methods: 10 individuals participating in a plaque regrowth trial were recruited and each had a QLF image taken of their anterior teeth (Mx and Mn canine to canine) following disclosure with PlaqueFinder. A separate image was taken of each tooth for a total of 12 per subject. Each image was then assessed using a combination of two image analysis tools and the percentage plaque index (PPI) calculated for each tooth. Three examiners undertook this, on two separate occasions with an intervening one-month washout period. The data from each attempt from each examiner were entered into SPSS and assessed using intra-class correlation coefficients and t-tests to detect any artefactual differences. Results: A total of 116 surfaces were captured and determined suitable for analysis. The examiners made a total of 696 planimetric measurements. Each reported that the technique was simple to undertake and only a minimal amount of subjective input was required. The mean PPI for all subjects was 37% (±13.2). ICC for intra examiner comparisons was above the 0.75 reliability level suggested by Fleiss, (ICC Ex 1, 0.98) and inter-examiner results were shown to be similarly reliable. Paired t-tests detected no significant differences between or within examiner attempts (p=0.05). Conclusions: The QLF planimetric technique permits good separation between tooth, plaque and surrounding tissues. This enables the image analysis software to objectively measure the PPI without substantial input from the examiner. The data suggests that QLF planimetry is reproducible both within and between examiners. ipretty@liv.ac.uk |