The Dental cosmos . (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 all
The Dental cosmos . (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 the same prism inlongitudinal, oblique, and transverse section. Fig. Perfect, grafted upon imperfect enamel. El, irregular and imperfect layer of enamel: ZT2, reg-ular layer of enamel; Z>, dentine ; I, interglobular spaces. X 500. In all the teeth I have examined with imperfect enamel, the so-calledinterglobular spaces were present in the dentine, indicating a deficientcalcification of territories at the period of development, which cor-responds with that of the formation of enamel. In only one specimenhave I seen a devious course of the dentinal fibers and stratificationof the dentine. 6l2 THE DENTAL COSMOS. In one instance peculiar formations were seen in the cementum.(See Fig. 7.) The cementum here exhibits distinct lamellations and scatteredcement-corpuscles, with their longitudinal diameters mostly arrangedvertically to the direction of the lamellae. The cementum wasabruptly interrupted by the dipping downward to the close vicinityof the dentine of the pericementum. In this situation the prolonga-tions of the pericementum we
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Keywords: ., bookauthor, bookcentury1800, bookdecade1890, booksubjectdentistry
