Detection of Carious Lesion by Laser Speckle Analysis Using the First Order Moment

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Carious lesion is one of the most prevalent diseases in humankind, affecting nearly all human beings at least once in a lifetime. Early carious lesion (ECL, also known as white spot lesion) is part of the caries process in which the enamel surface loses mineral but the subsurface layer overlying the mineral-poor region remains intact. In its early stages, the detection of the carious lesion is currently still a major challenge because it is based on visual inspection, thus with an inherent subjectivity. In this work, we present a method to detect and assess the severity of ECLs using a computer-assisted laser speckle imaging technique. Forty-five polished and cut bovine incisors samples allow a paired t-test by exposing half of the surface while protecting the other half. The samples, included in a PVC tube, were immersed in 50ml of a solution (pH 5.0) containing 0.05M acetate buffer solution and 50% saturated hydroxyapatite enamel powder at 37°C. The etching time is 24h; 48h and 72h; each group contain 15 samples. We illuminate each sample with a laser and analyse the first momentum of the laser speckle images with a computer. Our results shows that the first momentum of the LSI of the sound region statistically differs from the decay region of the samples for all groups (p).