File:The Dental cosmos (1891) (14781055792).jpg

Identifier: dentalcosmos3318whit (find matches)
Title: The Dental cosmos
Year: 1891 (1890s)
Authors: White, J. D McQuillen, J. H. (John Hugh), 1826-1879 Ziegler, George Jacob, 1821-1895 White, James William, 1826-1891 Kirk, Edward C. (Edward Cameron), 1856-1933 Anthony, L. Pierce (Lovick Pierce), b. 1877
Subjects: Dentistry Dentistry
Publisher: Philadelphia, S. S. White Dental Manufacturing Co
Contributing Library: Yale University, Cushing/Whitney Medical Library
Digitizing Sponsor: The College of Physicians of Philadelphia and the National Endowment for the Humanities

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Text Appearing Before Image:
andinstructive anomalies in the formation of this tissue, viz : two distinctvarieties of enamel, one upon the other. First we have the anoma-lous portion grafted or deposited upon a normal enamel, and againanomalous enamel first deposited, with the peripheral portion fairlynormal. (See Fig. 5.) This represents a cusp of a molar, with a conspicuously deficientenamel, deposited upon a nearly normal one. The normal portion isslightly pigmented, slightly stratified, and supplied with a moderatenumber of granulations, near the interzonal layer. The outer orperipheral portion exhibits a laVer which ends abruptly on one side, 6io THE DENTAL COSMOS. and gradually blends with the normal enamel on the other. This por-tion is remarkably deficient in its structure. At the boundary linebetween the two portions the enamel-prisms become abruptly devious,their longitudinal course being suddenly changed to a transverse one.In the latter portion a few oblique sections are seen alternating with Fig. 5.
Text Appearing After Image:
Imperfect, grafted upon perfect enamel. D, dentine: B, boundary zone (interzonal layer);jEs, perfect enamel; Ex, imperfect enamel. X 100. the transverse. The whole portion superadded to the normal ispierced by innumerable granulations, which, owing to their violetcolor, we must conclude as protoplasmic in structure and, of course,deficient in lime-salts. The granulations are, in some places, arrangedin rows, in others scattered irregularly. If a large mass of enamelexhibits prisms almost rectangularto their original normal direction,it is not an evidence of interlacing of such prisms, but of their unusu- CONGENITAL DEFECTS IN ENAMEL. 6ll ally wavy courses. An originally deficient enamel upon which isdeposited a normal one is represented in Fig. 6. Here we observe numerous layers made up of extremely narrow,interrupted prisms, and at a given line prisms of normal width appear,first in transverse, then in longitudinal sections. This specimenaffords a good opportunity to trace one and th

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