Page 174 - My FlipBook

174 THIRD PERIOD—MODERN TIMES

However, his description of the dental apparatus^ is far more exact
than that of Galen, and represents real progress. The number of the
roots of the molar teeth (large and small) is indicated by Galen in a
very vague and inexact manner, since he says that the ten upper molars
have generally three, sometimes four roots, and that the lower ones have
generally two, and rarely three. Vesalius, having examined the teeth
and the number of their roots in a great number of skulls, was able to
be much more precise. In regard to roots, he makes, for the first time,
a very clear distinction between the premolars next to the canine (small
molars) and the other three, and says that the former in the upper jaw
usually have two roots, and in the lower, one only, whilst the last three
upper molars usually have three roots and the lower ones two. As
everyone sees, these indications are, in the main, exact.
Other important facts established by Vesalius are as follows:
The canines are, of all the teeth, those which have the longest roots.
The middle upper incisors are larger and broader than the lateral ones,
and their roots are longer. The roots of the last molars are smaller than
those of the two preceding molars. In the penultimate and antepenulti-
mate molars, more often than in the other teeth, it sometimes happens
that a greater number of roots than usual are found, it being not very
rare to meet with upper molars with four roots, and lower ones with three.
The molars are not always five in each half jaw; sometimes there are
only four, either on each side, or on one side only, in only one jaw or in
both. Such differences generally depend on the last molar, which does
not always appear externally, remaining sometimes completely hidden
in the maxillary bone, or only just piercing with some of its cusps the thin
plate of bone which covers it; a thing which Vesalius could observe in
many skulls in the cemeteries.
In regard to the last molar, the author speaks of its tardy eruption
and of the violent pains which not unfrequently accompany it. The
doctors, he adds, not recognizing the cause of the pain, to make it cease
have recourse to the extraction of teeth, or else, attributing it to some
defects of the humors, overwhelm the sufferer with pills and other internal
remedies, whereas the best remedy would have been the scarification of
the gums in the region of the last molar and sometimes the piercing of
the osseous plate which covers it.
This curative method, of which no one can fail to recognize the im-
portance, was experimented by Vesalius on hmiself, in his twenty-sixth
year, precisely at the time that he had just begun to write his great treatise
on anatomy.

' Dc liumani corporis fabrica libri scptem, cap. xi, De clt-ntibus, pp. 40 to 42 (complete
edition of the works of Vesalius, pubbshed at Leyden in 1 725).