The anatomy, physiology, and diseases of the teeth / By Thomas Bell.

  • Thomas Bell
Date:
1837
Catalogue details

Licence: Public Domain Mark

Credit: The anatomy, physiology, and diseases of the teeth / By Thomas Bell. Source: Wellcome Collection.

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    which the various offices of the different teeth re- quire. ‘T’he part where the body and crown unite is termed the neck.* 3 There are two distinct substances which enter into the composition of the teeth, essentially differ- ing from each other in structure as well as in chem- ical composition ; the one being organized, the oth- er crystalline. The first,t of which the mass of the tooth consists, is true BONE; the second, which, from its appearance, is called ENaAmeL,{ forms only a thin layer over the body of the tooth, to which part it is distinctly restricted. The bony substance is of an extremely hard, dense structure; and, like other bones, is compos- ed of an earthy and a cartilaginous portion. ‘The earthy matter may be readily dissolved by immer- sion in dilute mineral acid ; and the cartilage which remains, still retains its form, and is found to be more.solid and compact than the same substance as it exists inother bones. ‘The fracture of this bone is shining, and slightly conchoidal. On a minute examination, and particularly if aided by the appli- cation of heat, it is seen to consist of concentric layers, the disposition of which is parallel to the surface of the tooth. It is extremely indistructa- ble ; so much so, that on opening barrows and oth- er ancient places of sepulture, the teeth are fre- quently found to have undergone scarcely any per- ceptible decomposition. The enamel is.an extremely hard, milky white, semitransparent substance, composed almost ex- ~clusively of earthy salts, principally phosphate of ‘lime, containing a trace only of animal matter. It is the hardest of all animal substances, and con- * Plate I. fig. 1, ¢, ¢. T Tb. figs 25a, 2: RS BE Loe SE
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