Scanning microscopic observations on XXXX .

@entity4625 @entity575 @entity11710 @entity1547 @entity505 @entity1068
This paper presents findings made using special techniques of imaging and/or of specimen preparation to investigate the changes in tooth structure which occur in caries. We have studied both coronal and root caries in enamel, dentine and cementum using scanning electron and confocal scanning optical microscopy. In preparation for backscattered electron (BSE) imaging in the SEM, teeth were stored in 70% @entity1068 until further dehydration in @entity1068 and embedding in polymethylmethacrylate ( @entity4625 ). Longitudinally cut surfaces were @entity11710 polished and coated with @entity505 or @entity575 before BSE imaging. Important changes in the distribution of densities in both enamel and dentine occurred during caries, and could be correlated with prior published studies using polarised light and microradiography to study demineralization in these tissues. However, the resolution of the BSE imaging technique is much higher than that of these previous methods. A new method was used for demonstrating local variations in microhardness with special relevance to the changes occurring in @entity1547 . Sectioned surfaces were subjected to treatment with a jet of soft abrasive particles, resulting in the selective removal of carious enamel, and enhanced removal of carious dentine. The tandem scanning reflected light microscope (ISRLM) has also been shown to be useful in characterising the spread of caries in the dental tissues. Teeth only need to be cut once, because the image is formed on looking into a bulk specimen. Fluorescent dyes can be used to study the distribution of pore volume, making use of the high resolution in depth of this confocal microscope.
