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COMPO UND CA VITIES. 293

before piittine^ tlie matrix in position, letting the ends of the cylinder
extend beyond the walls and into the space between the teeth. The
matrix is then put in place and rests upon the protruding ends of the
cylinders. These are condensed against the cervical border and the
o})eration is completed as previously described. The introduction of the
cylinders as stated, previous to the adjustment of the matrix, contributes
largely to the successful formation of a tight joint of the gold and the
cervical bonier. Or the same object may be accomplished with perhaps
greater certainty by adjusting a band matrix and screwing it tightly
into close contact Avith the tooth surfaces. When this is done there will
usually be found a slight space betAveen the matrix and the tooth at the
cervical border, caused l)y the band standing away from the tooth at
that margin. In filling this cavity the first pieces of gold, preferably
loosely rolled cylinders or mats, are grasped singly by the foil tweezers
near the end and passed endwise into the space between the matrix and

Matrix pluggers.
the cervical margin of the cavity. The end projecting into the cavity
is then bent inward and over the cervical margin and pressed firmly
down upon the cervical wall. Other pieces of gold are then similarly
introduced and condensed. This forms the foundation of the filling,
after which the operation is completed with cohesive foil as before de-
scribed. Tile advantages of this nu'thod are that the first ])ieces of
gold by being wedged between the nuitrix and the neck of the tooth
are immovably held, thus rendering the usual starting anchorages un-
necessary. This method also giyes positive assurance that the cervical
border is j)erfectly filled. The same perfection of joint at the lateral
maro'ins of the fillinii; may be attained where a band matrix of the Guil-
ford type is employed by slightly loosening the set-screw of the matrix
clamp as the operation proceeds, so that the band may be moved from
contact with the lateral margins of the cavity and the gold carried over
them as was done at the cervical margin. Moreover, when excessive
contour is desired it is easily accoinplislied In- a gradual loosening of