We investigated the detection and analysis of dental plaque using quantitative light-induced fluorescence (QLF). The QLF examination of the digital image of dental plaque was used to calculate the detected area (Area), the average red-fluorescence intensity (AR ave) and the maximum red-fluorescence intensity (AR max) in 10 healthy volunteers who refrained from tooth brushing for three days. Each of the three parameters increased at a different rate for the three days. We concluded that the QLF examination can distinguish and quantify the three parameters, and evaluate the rate of dental plaque formation.