Induction and 3D reconstruction of caries-like lesions in an experimental dental plaque biofilm model

The aim of this study was to examine an in vitro dental plaque model for vo lumetric assessment and 3D reconstruction of experimentally bacterial induc ed caries-like lesions. Twenty-three extracted, impacted human molars were coated with a varnish leaving a 3 x 3 mum window on the smooth surface. The teeth were coated with human saliva and Streptococcus sobrinus 6715 adhere d onto the enamel via a succrose dependent mechanism. The coated teeth were incubated for 1, 7, 14 and 28 days. At the end of each incubation period m icrohardness was measured on three sectioned teeth of each incubation perio d at the enamel surface and at 450 and 750 mum depth perpendicular to the e namel surface. The enamel surface was investigated by scanning electron mic roscopy (SEM) prior to embedding and serial sectioning of 12 other teeth. T he serial sections were studied with polarization light microscopy to inves tigate subsurface demineralization. The outlines of the caries-like lesions were then traced consecutively on transparencies, digitized and three-dime nsionally reconstructed to demonstrate the expansion of the lesion into ena mel for volumetric assessment. Microhardness was significantly reduced on t he enamel surface after 7, 14 and 28 days incubation. The SEM investigation showed a surface demineralization with dissolution of the prism cores afte r 28 days incubation. Polarization light microscopy demonstrated caries-lik e lesions with an irregular expansion into enamel. The results demonstrate that the described method produces caries-like lesions which can be used fo r further experimental studies regarding demineralization and remineralizat ion processes.