Field emission in-lens SEM study of enamel and dentin

This investigation used field emission in-lens scanning electron microscopy (FEISEM) for the study of tooth surfaces, with particular reference to adh esive bonding and acid conditioning. Dentin wafers with an intact enamel pe riphery were treated by either ethylenediaminetetraacetic acid (EDTA) (pH 7 .4) or phosphoric acid (pH 0.7). The samples were then fixed, sequentially dehydrated in alcohol, and either air- or critical point-dried. After coati ng, surfaces were examined by FEISEM. For enamel, intraprismatic crystals w ere clearly recognizable, with the crystals showing both a longitudinal and parallel orientation to the long axis of the prisms. For dentin, the surfa ce ultrastructure (mineral crystals and collagen banding) for the both untr eated and treated samples was observed. Fine structures measuring on the or der of 6 nm were also observed on samples treated by EDTA. We conclude that FEISEM can routinely provide high-resolution images of enamel and dentin, and that it has the capability of revealing the defined distribution of cry stals and collagen fibers in dental tissues. (C) 1999 John Wiley & Sons, In c. J Biomed Mater Res, 46, 315-323, 1999.