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372 RESTORATION OF TEETH BY CEMENTED INLAYS.
and discoloration of adjacent tooth structure, Avliile tlie adaptation of
the phistic metal to the tooth margins can he ({uite as ])erfect as though
no cement were used. So in using the principle of the inlay with
amalgam three distinct advantages are gained without any counteracting
disadvantages, all of which would seem to indicate that whenever possi-
ble zinc cement should be used under amalgam.
When an inlay of gold is cemented into a cavity with oxyphosphate
of zinc all the advantages of cohesive gold and oxyphosphate of zinc are
obtained, excepting that a line line of cement remaining at the margins
may in time prove a source of weakness. Except in the fine line above
mentioned, such a filling com[)ared with the ideal filling possesses ex-
cellent resistance to mastication and to the action of oral fluids, it has
power to restrain the growth of bacteria that may enter, it is a non-
conductor of heat, and is easy for the patient, while the manipulation
involves no greater labor or loss of tooth structure than is entailed in
the use of cohesive gold. The two objections that can be raised against
the filling are bad color and an edge protected by a soluble cement.
Hence — given a firm tooth structure that can bear the mallet without
danger of being crushed, a dentin not sensitive to thermal changes,
and a patient not too severely prostrated by the necessary malleting—
cohesive gold filling is superior to a gold inlay, inasmuch as the cohe-
sive filling may have edges that perfectly exclude bacteria, even though
it has no antiseptic action. Though the inlay largely inhibits from
growth the germs that enter its margins, it nevertheless does allow
them to enter ; and the filling that keeps out the germs entirely must
be held superior to the filling that admits germs and then inhibits or
destroys them. Unfortunately, in the soft, sensitive teeth of nervous
patients the manipulation of cohesive gold does not result in the exclusion
of decay germs. The tooth margins are powdered or weakened in some
way by the manipulation or apposition of the gold, and the entering
germs cause rapid decay, the cohesive gold not having the antiseptic
power of restraining them. The thermal shocks, and the overwrought
condition of the patient that sometimes lasts longer than can be avoided,
both tend to produce unhealthy conditions of the mouth and consequent
tooth dissolution. In such a mouth the inlay is indicated, as the patient
should not be made to undergo the malleting ; and since the germs of
decay will probably enter under any circumstances, it is necessary to use
a filling the action of which will inhibit or prevent their growth.
In approximal cavities where the filling does not show, and where
great resistance to the percussive force of mastication is necessary, the
gold inlay is usually to be preferred. Its sole objection is the fine line
of cement that connects it with the cavity walls ; but if the gold inlay
be properly prepared, burnished, and finished as hereafter described.
372 RESTORATION OF TEETH BY CEMENTED INLAYS.
and discoloration of adjacent tooth structure, Avliile tlie adaptation of
the phistic metal to the tooth margins can he ({uite as ])erfect as though
no cement were used. So in using the principle of the inlay with
amalgam three distinct advantages are gained without any counteracting
disadvantages, all of which would seem to indicate that whenever possi-
ble zinc cement should be used under amalgam.
When an inlay of gold is cemented into a cavity with oxyphosphate
of zinc all the advantages of cohesive gold and oxyphosphate of zinc are
obtained, excepting that a line line of cement remaining at the margins
may in time prove a source of weakness. Except in the fine line above
mentioned, such a filling com[)ared with the ideal filling possesses ex-
cellent resistance to mastication and to the action of oral fluids, it has
power to restrain the growth of bacteria that may enter, it is a non-
conductor of heat, and is easy for the patient, while the manipulation
involves no greater labor or loss of tooth structure than is entailed in
the use of cohesive gold. The two objections that can be raised against
the filling are bad color and an edge protected by a soluble cement.
Hence — given a firm tooth structure that can bear the mallet without
danger of being crushed, a dentin not sensitive to thermal changes,
and a patient not too severely prostrated by the necessary malleting—
cohesive gold filling is superior to a gold inlay, inasmuch as the cohe-
sive filling may have edges that perfectly exclude bacteria, even though
it has no antiseptic action. Though the inlay largely inhibits from
growth the germs that enter its margins, it nevertheless does allow
them to enter ; and the filling that keeps out the germs entirely must
be held superior to the filling that admits germs and then inhibits or
destroys them. Unfortunately, in the soft, sensitive teeth of nervous
patients the manipulation of cohesive gold does not result in the exclusion
of decay germs. The tooth margins are powdered or weakened in some
way by the manipulation or apposition of the gold, and the entering
germs cause rapid decay, the cohesive gold not having the antiseptic
power of restraining them. The thermal shocks, and the overwrought
condition of the patient that sometimes lasts longer than can be avoided,
both tend to produce unhealthy conditions of the mouth and consequent
tooth dissolution. In such a mouth the inlay is indicated, as the patient
should not be made to undergo the malleting ; and since the germs of
decay will probably enter under any circumstances, it is necessary to use
a filling the action of which will inhibit or prevent their growth.
In approximal cavities where the filling does not show, and where
great resistance to the percussive force of mastication is necessary, the
gold inlay is usually to be preferred. Its sole objection is the fine line
of cement that connects it with the cavity walls ; but if the gold inlay
be properly prepared, burnished, and finished as hereafter described.
