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Chapter UTTT.
technique of Tinishing and Setting Tnlays.

After the fusing process has been completed, the matrix sliould be
removed by gripping it with the lock tweezers and peeling the foil toward
the center of the inlay. It may be necessary to catch the matrix at
different points in order to loosen it at the margins. If the porcelain and
the metal adhere firmly, this adhesion may be partially broken by plac-
ing the inlay and matri.x in water for a few minutes, and the foil may
then be removed more easily. If there were any perforations in the
matrix, through which some of the porcelain has flowed, the adhesion
will be greatest at these points, and it will be almost impossible to remove
the matrix without some method of instrumentation. When these points
of adhesion are somewhat distant from the margin the foil may be re-
moved with a small stone or a dull bur ; but if such points of contact are
along the margin the metal should be removed with an excavator.
Unless this is done delicately the inlay may be chipped along the mar-
gin. In order to prevent this chipping all scraping should be from the
margin toward the center of the inlay. In case it seems inadvisable to
remove a small piece of foil at the margin by instrumentation the inlay
may be placed in hot aqua rcgia until the foil is dissolved.
The inlay should be grooved after it has been
separated from the matrix. This may be done best
Cutting
with a small diamond disk (Fig. 129), which may
6roo«e$.
be used as a copper disk with carborundum powder
after the diamond dust has worn off. The location and depth of the
grooves depend upon the size and shape of the inlay. When the inlay is
for a cavity on the labial or buccal surface, the groove should extend
around its circumference near the base (Fig. 130A). If, however, the
inlay is constructed for a simple approximal or approximo-incisal cavity,
the groove should be formed along the ridge of the inlay that fits into
the cavity (Fig. 131A). It is also advisable to make a groove along the
seat extending in a labio-lingual direction. In all cases in which the

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