Page 84 - My FlipBook
P. 84
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82
represented at seven years only forty four, and at nine years
forty eight, excepting that at the latter period the middle tem-
porary incisores of the under jaw had been shed. Although I
omitted saying any thing particularly respecting the forma-
tion of the permanent teeth, when treating of the ossifica-
tion on the pulp of the temporary ; I think however from
the observations then made, a few words more will now
suffice.
The incisores and cuspidati resemble their predecessors
but are much larger, but those which succeed the tempo-
rary grinders differ very much from them, in size and shape,
being about one third smaller. Ossification commences on
them in genera] by two points, ihe shells formed round each
of these gradually unite, and ossification goes on then for
some time as in the incisores and cuspidati, until the greater
part of the root is formed, which commonly divides in the
upper jaw into two processes near the extremity. I have
met sometimes two distinct roots proceeding from the neck
in the under jaw in general they have but one root. Now
the grinders which they succeed have four or five points on
their grinding surface, and in the upper jaw they have com-
monly three distinct roots ; in the under jaw two. Nor, ac-
cording to the celebrated Albinus, do they differ only in their
number of points, but in their entire figure, by which we can
readily distinguish one from the other. Although the accur-
ate Eustachius remarks, those of the under jaw in general
want the internal point, I think the term bicuspides, which
Mr. Hunter has given, is sufficiently applicable, as it at once
distinguishes them from the temporary grinders ; on which
account I retain it, particularly as it has been the term made
use of in practice for some years since.
As to the permanent grinders, the anterior hnve each five
points, the middle grinders four, sometimes five points, ajid
82
represented at seven years only forty four, and at nine years
forty eight, excepting that at the latter period the middle tem-
porary incisores of the under jaw had been shed. Although I
omitted saying any thing particularly respecting the forma-
tion of the permanent teeth, when treating of the ossifica-
tion on the pulp of the temporary ; I think however from
the observations then made, a few words more will now
suffice.
The incisores and cuspidati resemble their predecessors
but are much larger, but those which succeed the tempo-
rary grinders differ very much from them, in size and shape,
being about one third smaller. Ossification commences on
them in genera] by two points, ihe shells formed round each
of these gradually unite, and ossification goes on then for
some time as in the incisores and cuspidati, until the greater
part of the root is formed, which commonly divides in the
upper jaw into two processes near the extremity. I have
met sometimes two distinct roots proceeding from the neck
in the under jaw in general they have but one root. Now
the grinders which they succeed have four or five points on
their grinding surface, and in the upper jaw they have com-
monly three distinct roots ; in the under jaw two. Nor, ac-
cording to the celebrated Albinus, do they differ only in their
number of points, but in their entire figure, by which we can
readily distinguish one from the other. Although the accur-
ate Eustachius remarks, those of the under jaw in general
want the internal point, I think the term bicuspides, which
Mr. Hunter has given, is sufficiently applicable, as it at once
distinguishes them from the temporary grinders ; on which
account I retain it, particularly as it has been the term made
use of in practice for some years since.
As to the permanent grinders, the anterior hnve each five
points, the middle grinders four, sometimes five points, ajid
