Phillipsburg, NJ, USA) under ultrasonic vibration for 20 minutes, which led to it’s selective enamel demineralization. Subsequently the teeth were quenched in distilled water for 1 hour in order to neutralize the acid and facilitate handling. The specimens were photographed (D200 Nikon Inc., Melville, NY, USA) on a custom fabricated tripod-jig (XX-Halter, Novoflex, Memmingen, Germany) maintaining standardized illumination, exposure settings and perspective, prior to and after the acid treatment, in order to ensure proper alignment of
a
b
c
Fig 3 The DEJ when examined histologically provides a visual interface yet when examined on a bio- mechanical level, it is regarded as a functional interphase. As seen above the frontal longitudinal histological tooth section of a maxillary premolar 0.5mm in thickness was submerged in distilled water and photographed on a black background in depiction (a) . The same specimen was photographed by transmissive cross polarized illumination (b) . Highlighted is the extended DEJ complex. (c)
the superimposed images.
DEJ AS THE STRUCTURAL EPICENTER OF AN INTERPHASE BETWEEN ENAMEL AND DENTIN
One must examine the significance of the DEJ as an important factor in the understanding of the developmental adaptation of the surface pattern of enamel expression. During odontogenesis this junctional interface serves as the histologic blue print (FIG 1.), representing a complex inter-digitation zone between two distinct anisotropic calcified tissues with different
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