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New diagnostic techniques, such as electrical conductance and quantitative light-induced fluorescence (QLF), have been developed for the quantification of caries in fissures. The aim of this study was to develop an intra-oral model in which caries is formed in human enamel fissures and to measure the caries with transverse microradiography (TMR) and QLF. Extracted human premolars were selected in which caries could not be detected by visual inspection or by TMR. The premolars were cut such that only the occlusal part was placed in the partial dentures of 24 panelists. The panelists promoted caries formation by placing a drop of 10% sucrose on the specimen for 5 min twice per day. The first group of volunteers returned after 1 month, the second after 2 and the last after 3 months. Upon retrieval of the specimens, an image of the fissure of each specimen was analysed with QLF. Sections were cut for TMR and analysed. In the lower part of fissures, microradiographic analysis found sub-surface lesions. After 1 month intra-orally, TMR found only 1 lesion with a mineral loss of 1,560 vol.%·µm, while QLF found 6 lesions with an average fluorescence of -9%. After 2 months, TMR found 3 lesions with an average lesion size of 2,563 vol.%·µm (SD 1,019) and QLF found 7 lesions with an average fluorescence of -11%. After 3 months, TMR found 5 lesions with an average lesion size of 1,927 vol.% ·µm (SD 1,345) and QLF found 6 lesions with an average fluorescence of -8%. In the in situ model presented lesions in fissures were formed which resembled naturally formed lesions and which could be analysed with fluorescence and microradiography. |