A system of dental surgery / by the late Sir John Tomes.

  • Tomes, John, 1815-1895.
Date:
1897
Catalogue details

Licence: Public Domain Mark

Credit: A system of dental surgery / by the late Sir John Tomes. Source: Wellcome Collection.

    14/764 (page 2)
    and development of the jaws and teeth, but also to a great extent the details of the data upon which they were based. But now that the deductions drawn from the large, and at that time unique, collection of young skulls of known ages have obtained general acceptance, and that other works treating of special dental anatomy are in existence, it does not seem necessary to enter into such full detail, so that the old chapter upon teething is greatly abridged in this edition. If two perfectly healthy children, whose ages are the same, be selected for examination, we shall rarely find that they present precisely similar conditions as regards the rate of teething ; yet there will probably be no great disparity in the conditions of the two. There is, however, another source of fallacy to be guarded against. The specimens obtained are necessarily taken from in- dividuals who have been the subjects of disease ; and, supposing the fatal illness to have been of long standing, the jaws may have been modified. That this has occurred to some members of the series is sufficiently obvious, but the diseased action appears to have influenced the growth of the jaws themselves rather than the rate of development of the teeth. And it is a remarkable fact that there is more fixity about the teeth than about the jawbones under the influence of inherited or of pathological varia- tions ; thus in short-muzzled dogs the teeth do not diminish in size proportionately with the shortening of the face, so that they come to be crowded, and the same thing is every day observed in the human subject, even in cases of rickets. Hence even these specimens may serve to confirm the results obtained from an examination of healthy jaws, so far as the teeth are concerned. The fact that the development of the hard tissues of a tooth is px-eceded by the foi-mation of soft tissues, or tooth- pulps, of size and form equal to the future tooth, must at all times be kept in view. Not that the entire pulp assumes the dimensions of a perfected tooth before its conversion into the hard tissue commences, but that each individxial part of the developing tooth is fii'st formed in pulp tissue of its full size and then calcifies. In dentine, which forms the great bulk of each tooth, we have no such thing as outward growth ; no addition to the external surface of the formed tissue ever takes place,