Dental cosmos . These latter no doubt arise by aslight shrinking of the cells rich in water, when they are fixed withosmic acid. But such preparations prove that there is no firm con-nection between the various odontoblasts, as is the case with epithelialcells. It is well known that the deposition of dentine on the surface of thepulp continues throughout life. The energy of growth decreasesconsiderably with the increase of age in such teeth where the growthof the root is limited. The growth ceases altogether on some places;on others it continues. It also .happens that on places where thedeposi
Dental cosmos . These latter no doubt arise by aslight shrinking of the cells rich in water, when they are fixed withosmic acid. But such preparations prove that there is no firm con-nection between the various odontoblasts, as is the case with epithelialcells. It is well known that the deposition of dentine on the surface of thepulp continues throughout life. The energy of growth decreasesconsiderably with the increase of age in such teeth where the growthof the root is limited. The growth ceases altogether on some places;on others it continues. It also .happens that on places where thedeposition of dentine has stopped for a long period, a renewed depo-sition of dentine (reserve dentine) takes place in consequence ofexternal stimuli. It can easily be proved that in proportion as theenergy of growth decreases, so do the odontoblasts decrease in Fig. 10, on the upper end of the pulp the formation of dentine isstill going on. This is evident, as here there is still a layer of uncal- Fig. Fig. 9.—Protopterus. Odontoblasts, Od, from the dental plate of the lower jaw ; VD, vitro-dentine. Ground section after v. Kochs petrifying method. Hartnack 8. Oc. 2. cified dentine present. In consequence of its extension the odonto-blasts have inaeed decreased considerably in height, but they still forma continuous layer resembling epithelium. The deposition of dentinehas stopped for a time on the other parts of the surface of the pulp,and, concluding from the course of the dentinal tubules, it had beenirregular for some time before that. The odontoblasts have here avery much altered appearance, and greatly resemble the odontoblasts are at many points no more in connection with one; another ; after a time these cells, their function having ceased, ap-proach again, in form and mutual position, those cells from whichthey arose,—viz, embryonic connective-tissue cells. Even the simple tissue of the normal pulp has been described sodifferently by the pre
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Keywords: ., bookauthor, bookcentury1800, bookdecade1890, booksubjectdentistry
