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To date, most studies on QLF (quantitative light-induced fluorescence) have been performed under reduced lighting conditions, which may not be practical in a dental clinic. The purpose of this study was to evaluate two ways of reducing clinical ambient light, a novel ambient light shield and successive layers of rubber dam. The effect was estimated by comparing the outcome of lesion analysis. Twenty-nine natural lesions [11 occlusal (OC), 11 white spot (WS) and 7 brown spot (BS) smooth surface lesions] were selected on extracted teeth (stored in 3% formalin). QLF images were taken using video repositioning under regular ambient light conditions, and by using an ambient light shield specially fitted on the camera handpiece. Additionally, images were taken with up to 4 layers of rubber dam (heavy) and under reduced lighting; these images served as control. Correlations were modeled as unstructured, and comparisons within lesion type were made using Sidak adjustment. Fluorescence loss (.F) and area were affected by the lighting conditions, with both variables decreasing as the light increased. WS smooth surface lesions were most affected, BS to a lesser extent and OC lesions least. Three layers of rubber dam achieved a light level equivalent to reduced lighting. The light shield changed the lighting conditions, increasing the excitation intensity, reducing measured .F (OC = 5.4%, WS = 35.2, BS = 23.6), pd0.001 for WS and BS. It also made the level of ambient light irrelevant. In conclusion, analyses of images taken with the new ambient light shield give different results than were obtained from images taken under reduced lighting conditions, but were unaffected by the level of ambient light. |