Licence: Public Domain Mark
Credit: A manual of dental anatomy : human and comparative / by Charles S. Tomes. Source: Wellcome Collection.
Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.
46/614 (page 32)
![hy alterations in the focus of the microscope the appeai'ance (jf the tul)e mal.ing a spiral turn is made very striking. The effect of an elongated spiral viewed on its side will be that of only slight undulations, such as are the secondary curvatures of the tubes. The spiral course of the dentinal tubes is most strongly marked in the roots of teeth. When a transverse section of dentine is viewed, bands or rings, concentric with the pulp cavity, are seen, and the same bands may be seen in longitudinal section. Such a striated or laminated appearance in the dentine may be due to two causes ; and some little confusion has arisen in the nomen- clature, owing to its double origin not having always been kept in view. Such stria) may be due to the presence of rows of interglo])ular spaces, or to the coincidence of the primary curvatures of neighbouring dentinal tubes : that is to sa}', each tube bends at the same distance from the surface, and the bend makes a difference in the optical properties of the dentine at that point. Schrcgcr described these latter: the lines of Schreger, therefore, are markings, rangeil parallel with the exterior of the dentine, which are due to the curvatures of the dentinal tubes. Tlie contour lines of Owen, even in his own works, include markings of both classes : i.e. those due to tlie ■curvature of the dentinal tubes, and those due to lamina^ of interglobular spaces, such as are met with in the teeth of (Jetacoa. Eetzius had seen and described contour markings due to interglobular spaces, though his name is not usually associated with them, the brown strito of lietzius beino- markings in the enamel. The tubes as they i)ass outwards often divide into two •equally large In-anciies : tiiey also give off fine branches, wliich anastomose witli those of neighbouring tubes. In tlie crown of a human tooth these fine l)ranches are compara- tively few, until the tube has reached nearly to the enamel,](https://iiif.wellcomecollection.org/image/b21932025_0046.jp2/full/800%2C/0/default.jpg)
