File:Journal - American Medical Association (1883) (14584779570).jpg

Identifier: journalamericanm14ameruoft (find matches)
Title: Journal - American Medical Association
Year: 1883 (1880s)
Authors: American Medical Association
Subjects: Medicine Medicine Medicine (General) Periodicals
Publisher: Chicago
Contributing Library: Gerstein - University of Toronto
Digitizing Sponsor: Ontario Council of University Libraries and Member Libraries

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tothese defects, in this location, although Wedlmay have mentioned them. Dr. Allen sajs thatcalcification commencing on the prominences ofthe cusps gives rise to as many points of calcifi-cation as there are cusps. When they meet, fromsome unknown cause, these cusps do not alwaysunite. Am«ng other places faults of this kindare found on the cervical portion of the enamel,midway between the buccal and palatal faces.They differ from those found on other portions ofthe tooth, in that they resemble more closely anordinary crack, that might have been caused bymechanical force or dessication. I can attest tothe correctness of Dr. Allens assertion by sec-tions made across this portion of bicuspid teeth.These show crevices or cracks through theenamel in width sufiicient to admit of infectionby any of the microorganisms found in decayedteeth. DESCRIPTION OF PLATE. Fig. I.—Section of crown of bicuspid tooth through the fissure from mesial to distal surface, showing a tract of imperfectly de-
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i890.) RETINAL EMBOLISM. 527 vclopfil dentine and the white zones of partially decalcifiedmatrix uniler the fiisure. About 50 diameters. Fio. -•—The Imperfectly developed dentine under a hiifh power,showing masses of globules of various aizes, and an interglobularsubstance of a much less dense structure everywhere Betweenthem. The tissue is infected, the tubules being distended by mi-croorganisms. About 1500 diameters. Fic. J.—Cross section of calf tooth at birth. A. laydentine; B. layer of calcoglobulin ; C. lay - --pulp tissue. About 200 diameters, Fio. 4. —From tooth of human fcctus, sixth month, vertical sec-tion, showing the deposit of calcospherites on the formed dentinefroni the enamel pulp. A. outer edge of formed dentine ; B. smallglobular masses, calcospherites. About 1200 diameters Fi<i. s.—Cross section of calf tooth at birth, showing a formingband of dentine. The layer is seen to be made up by the coalescingof the globular masses. A, forming band of dentine ;

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