A computerized analysis of the relation between the occlusal enamel caries lesion and the demineralized dentin

It has previously been shown that the demineralized dentin does not spread laterally along the enamel-dentin junction in non-cavitated approximal lesions. This study examined the spread of the dentinal part of occlusal lesions along the enamel-dentin junction. The material consisted of 48 well-defined occlusal lesions with histological evidence of dentin demineralization. The teeth were embedded in methylmethacrylate, serially-sectioned, ground, and contrast-stained. The sections with the deepest lesion penetration from each lesion were photographed and scanned by a high-quality scanner in order to produce images for computerized histomorphometric analysis. Two variables were measured on the images: i) the length of the contact area of the enamel lesion along the enamel-dentin junction; and ii) the length of the contact area of the demineralized part of the dentin lesion along the enamel-dentin junction. The results showed a gradual increase in the lengths of the enamel and dentin contact areas between the sections, each representing well-defined progressive stages of lesion formation. In two-thirds of the non-cavitated lesions, the enamel lesion was larger than the demineralized part of the dentin lesion, and in 50% of the cavitated cases the extension of the demineralized dentin was less than the affected enamel. Our conclusion is that the dentin demineralization did not spread significantly in a lateral direction in non-cavitated occlusal lesions.