Principles and practice of operative dentistry . Section of root, parallel to dentinal canals. (After Stowell.) face the division is more rapid, and the size of the branches is correspond-ingly decreased. At the external surface of the dentin many of thetubules unite by anastomosis (Fig. 158), others terminate in the granularlayer of Purkinje and Tomes, while a third set penetrates the cementumand may unite with its lacunae through their canaliculi ; or enter theenamel by means of the open spaces, or interstices between the enaniel- Fig. 1, tubuli of dentin ; rods, already referred to as
Principles and practice of operative dentistry . Section of root, parallel to dentinal canals. (After Stowell.) face the division is more rapid, and the size of the branches is correspond-ingly decreased. At the external surface of the dentin many of thetubules unite by anastomosis (Fig. 158), others terminate in the granularlayer of Purkinje and Tomes, while a third set penetrates the cementumand may unite with its lacunae through their canaliculi ; or enter theenamel by means of the open spaces, or interstices between the enaniel- Fig. 1, tubuli of dentin ; rods, already referred to as existing in that portion of the enamel next tothe dentin (Fig. 159). This system of canals terminates, or rather has itsbeginning, in free openings upon the internal surface of the pulp-canal. 44 OPERATIVE DENTISTRY. Fig. 160, which, is highly magnified, shows the dentinal fibrillse crossingfrom the dentin to the enamel and apparently passing between the enamelrods. The Dentinal Sheaths.—The dentinal sheaths, or walls of the tubuli,as they are termed, are composed of a singularly indestructible substance,which is peculiarly resistant to the action of acids, boiling in caustic alka-lies, or to putrefaction ; caries does not destroy them, and they can also bedemonstrated in fossil teeth; this substance is in all probability calco-globulin. Neumann and Henle are of the opinion that the dentinal sheaths arecalcified. The existence of the dentinal sheaths can be demonstrated bydecalifying the dentin with strong acids. This process requir
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectdentist, bookyear1901
