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

  • John Tomes
Date:
1897
Catalogue details

Licence: Public Domain Mark

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

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    dental arch than their respective roots; the crown of each tooth is directly over or under (as the case may be) its own root, the latter standing immediately in front of one or other of the successional teeth. On removal of the bone from the anterior surface of the maxilla, it will be seen that the permanent central incisors are placed nearly parallel with each other, the cutting edges in the upper teeth being inclined a little forwards, while the parts corresponding to the base of the crowns of the two teeth respectively are placed immediately below the floor of the nose, from which cavity they are separated by a thin layer of bone only. The teeth at this stage of growth com- pletely fill the cells or crypts. The corresponding lower teeth hold a similar position in the lower jaw, but have a strictly vertical position, and show a slight advance in develop- ment as compared with the upper. centrals. The lateral incisors of the upper jaw have a slightly oblique direction, the cutting edges being more forward than the base of the crowns, which are nearly on a level with the corresponding parts of the central teeth. The cutting edge of each is often slightly turned, so that the mesial surface which lies against the central incisor is directed outwards, while the mesial angle of the tooth stands in front of, and a little over, the contiguous portion of the central incisor. The point at which the one tooth overlaps the other corresponds to the position of the root of the temporary lateral incisor. That side of the lateral, which in the perfected tooth lies against the canine, here rests against the cell which contains the first bicuspid ; while the developing canine is at this period above the latter tooth. In the lower jaw the lateral incisors are placed less regularly, holding a position slightly more backward than the centrals. The tooth on either side is turned from the median line, and lies obliquely over the canine, to the extent of about half of that tooth. They do not, however, as in the upper jaw, come in contact with the cells that contain the first bicuspids. The eruption of the teeth without change from these positions is a common source of slight irregularity. The permanent canine teeth at this stage of dentition are situated above the line of the other teeth in the upper, and
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