Page 109 - My FlipBook

EXCAVATORS. 105

a spring temper, in which the color, when drawn,
is a deep blue. These instruments are used for en-
larging the canals of fangs for the purpose of filling.
Six or eight sizes will probably meet all ordinary
cases. When the course into the canal is tortuous,
the temper of the instrument should be so low as to

spring readily.

EXCAVATORS.

Of the small cutting-instruments for opening and
forming cavities and removing decay from them, there
is a great variety, though a few general forms com-
prise the whole. Hitherto there has been no very
systematic arrangement of these instruments, such as
the convenience both of the profession and the man-

ufacturers of dental instruments would seem to dic-
tate, In a classification that we have adopted and
found very convenient, they are arranged by num-
bers, the most simple being placed under the first, and
under each successive number a more complicated
form. All the varieties are embraced in twelve
numbers, which are represented in Figs. 18 and 19.
These varieties are discriminated by the forms of the
points and their position on the shaft to which they

are attached, and not by any curve which the shaft
may have at any distance from the point.