Читать книгу Applied Oral Physiology - Robin Wilding - Страница 13

The disorientation of crystals in the interprismatic zone makes it more susceptible to acid demineralization than the well-orientated crystals of prismatic enamel. It is the interprismatic zone which first demineralizes due to early caries. However, the dissolution pattern varies when organic acids are used to etch enamel. Etching enamel is a routine procedure when using restorative resins, because the resin bonds to a roughened surface better than to a smooth one. The two common etching patterns are etching of the prism center and etching of the interprismatic substance (▶ Fig. 2.4).

Fig. 2.1 A diagrammatic representation of the formation of enamel prisms during tooth development. Ameloblasts secrete enamel prisms parallel to each other with the enamel crystals orientated in the same direction. In the interprismatic zone, the crystals turn outward. The enamel matrix is secreted and mineralized by the ameloblast (red arrow), and the protein then resorbed (blue arrow).

Fig. 2.2 A magnified view of a fractured enamel surface reveals parallel prisms packed together. Scanning electron microscope (SEM) image (magnification × 300) of an enamel surface, prepared by fracture in the direction of the enamel prisms. The fractured surface reveals enamel prisms stacked like the grain in a log of wood. The surface of the tooth was etched to reveal the ends of the enamel prisms.