Page 384 - My FlipBook

382 RESTORATION OF TEETH BY CEMENTED INLAYS.

firmly held with the index and middle fingers of the left liand, while
the right hand presses the metal with cotton partly into the cavity. The
margins and floor of the matrix may then be defined with a bnrnisher.
In mesial cavities the metal must be pushed away from the operator
and the work accomplished by means of the index and middle fingers,
as in Fig, 301, In distal cavities the metal is pulled toward the oper-
ator, who works around and beyond the hand, holding the platinum as
in Fig. 362.
When, as sometimes occurs, the adapted platinum is dovetailed
around the teeth, so as to render its removal difficult or impossible with-

FiG. 365.

Position of fingers : left lower bicuspid.

out distortion, the outer edge of the platinum cap may be split with a
sharp knife from the gum line, just beyond the cavity margins, as is
shown in Fig. 363. Fig. 364 shows a method of obtaining immobility
of the matrix by a clamp that sometimes proves useful. Figs. 365
and 366 show the position of the fingers when manipulating the
matrix on the lower teeth. This, of course, should be done while the
matrix is held motionless in the cavity. It is sometimes advisable, in
order that perfect immobility may be obtained, first to pack the matrix
full of bibulous paper or cotton. When this is done and the packing