Page 121 - My FlipBook

OF THE ARTICULATION OF THE TEETn. 105
this weakness in the Upper-Jaw is for the increase of the
Antrum is probable, because all the Teeth in the Upper-Jaw
are a good deal similar to those in the Lower, excepting
those that are opposite to the Maxillary Siinus ; and here they
differ principally in the fangs, without any other apparent
reason ; and what confirms this, is, that the Dentes Sajcrientice
in both Jaws are more alike than the other Grinders ; for this
reason, as I apprehend, because the Dens Sapientice in the
Upper-Jaw, does not interfere so much with the Maxillary Sinus.
What makes it still more probable that the two first superior
Grinders have three fangs on account of the Maxillary Sinus,
is, that the two Grinders on each side of the Upper-Jaw, in the
child, have three fangs, and we find them underneath the
Antrum; but those that succeed them have only one fang, as
in the Lower-Jaw ; but by that time the Antrum has passed
further back, or rather the arch of the Jaw has projected, or
shot forwards, as it were, from under the Antra, so that the
Alveolar Processes that were under the Antrum at one age, are
got before it in another.
That the edge of every fang is turned towards the circum-
ference of the Jaw, in order to counteract the acting power, we
shall see when we consider the Motion of the Jaw, and the Use
of the Teeth.
OF THE ARTICULATION OF THE TEETH.
The fangs of the Teeth are fixed in the Gum and Alveolar
Processes, by that species of Articulation called Gomphosis,
which, in some measure, resembles a nail driven into a piece
of wood.
They are not, however, firmly united with the Processes, for
every Tooth has some degree of motion ; and in heads which
have been boiled or macerated in water, so as to destroy the
Periosteum and adhesion of the Teeth, we find the Teeth so
loosely connected with their sockets, that all of them are ready
to drop out, except the Grinders, which remain as it were
hooked from the number and shape of their fangs.