Assessing the efficacy of denture cleaners with quantitative light-induced fluorescence (QLF).

The aim of this study was to evaluate Quantitative Light Induced Fluorescence (QLF) analysis as a means of determining the ability of denture cleaners to remove stain from denture teeth. This study investigated the appearance of acrylic resin denture teeth subjected to QLF conditions in vitro. It aimed to determine if QLF was an appropriate method for detecting stain and its removal on acrylic resin denture teeth in vitro and also to develop a quantitative and reproducible method for assessing the efficacy of denture cleaners using QLF. This study showed that not all acrylic resin denture teeth fluoresced under QLF examination. QLF demonstrated the ability to detect and quantify longitudinal changes in stain removal by the various denture cleaners used in the study.

Validation of enamel erosion in vitro.

OBJECTIVES: Many tools are available to quantify dental erosion, but each technique has its own inherent disadvantages. This study aims to validate the use of quantitative light-induced fluorescence (QLF) and non-contacting surface profilometry compared to the gold standard transverse microradiography (TMR) for the quantification of enamel erosion in vitro. METHODS: This was an in vitro laboratory based study. 60 bovine incisors were divided into 6 groups of 10. Each tooth's labial surface was completely varnished except for a window of enamel approximately 3mmx5mm. Each was baseline imaged with QLF and non-contacting surface profilometry before being subjected to an erosive solution (pH 3.4) for up to 36h. The lesions were imaged using non-contacting surface profilometry and QLF, sectioned and analysed with TMR. Correlation coefficients were calculated to assess the validity of the methods of measurement as compared to TMR. RESULTS: A range of lesion severities resulted. Mineral loss measured as DeltaQ (QLF) and step height (profilometry), was recorded and confirmed by TMR. A correlation was found between DeltaZ (TMR) and profilometry lesion depth of r=0.648 (p<0.001). A poorer correlation was found between DeltaZ and DeltaQ: r=0.217 (p=0.096). CONCLUSIONS: Profilometry lesion depth and DeltaZ correlated significantly. Both methods allow for quantification of erosive crater depth. QLF correlated poorly with DeltaZ, but is useful for measuring subsurface loss of mineralisation. TMR is valuable but is destructive and can only be used in vitro. Currently only QLF can be used in vivo. Advances in these technologies may allow the development of non-destructive in vivo measurements of mineral loss, combining the positive features of each measurement method.