A system of dental surgery / by John Tomes and Charles S. Tomes.

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

Licence: Public Domain Mark

Credit: A system of dental surgery / by John Tomes and Charles S. Tomes. Source: Wellcome Collection.

    184/776 (page 172)
    would present a serious obstacle to its movement back- wards. Should it be determined to bring an outstanding canine into the dental line, either by acting on the tooth itself, or by operating on the neighbouring teeth, as well as upon the canine, the method described as having been successful in turning into jdace a twisted central incisor will be found eflective; or a vulcanite plate may be used, if the operator regards metallic regulation plates with distrust. Irregularity in the g}osition of the bicuspids.—It rarely happens that the front teeth are crowded, without the bicuspids to some e.\tcnt participating in the general irregu- larity. They are usually situated internally to the normal position, and are instrumental in throwing the canines out of the proper line, or in giving the appearance of undue prominence to those teeth. The bicuspids may be regarded as forming the base of the semicircular dental curve, which, if contracted, necessarily involves either a deviation from the normal figure, as seen in the Y-shaped mouth, or it obliges some of the teeth to take either an external or an internal position. If the curve described by a jicrfectly well-arranged set of teeth bo examined, it will be found that it approaches a semicircle as far as the bicuspids, and that the molars occujiy curvilinear lines, diverging slightly as they i>rocced back- wards. The arch admits of division into two parts; the anterior semicircular portion being occupied by the successors of the deciduous teeth, the posterior division by the true molars—teeth Avhich have no predecessors. Should, there- fore, the breadth of the jaw at the junction of the two divisions fall bclow' the proper extent, and the bicuspids of either side consequently approach too near the median line, not only will the front teeth be thrown out of the semi- circular curve, but the molar teeth will occupy lines which, although diverging from the starting-points, will nevertheless fail to attain an amount of separation as respects the two