Page 67 - My FlipBook

OXYPHOSPHATE OF ZINC. 53

tooth for examination. Thus its failures can be more accurately
counted than its successes. Another fact to be considered is, that
just
as in the case of erosions, the action of the would
physiological pulp
have the same tendency toward self- protection against the advance of
ordinary caries. Indeed, where the carious action happens to be slow
find it aborted
we not infrequently by the resistant quality of the new
dentine formed, so that we get what has been termed ' ' arrested decay. ' '
It follows from this that whose action is
any filling sufficiently nega-
tive not to interfere with the ordinary healthy action would seem to
produce the desired result, merely because it does not prevent it. It
is probable that where the oxychloride succeeds, it acts just as other
materials do, by not creating an irritation.
That an does possess some
oxychloride filling therapeutic qualities
seems indicated by the fact that it may usually be depended upon to
lessen the sensitiveness of dentine if left in a a month or more.
cavity
This of course may occur under one of oxyphosphate simply because
the tooth itself has altered, but as it has in my observation occurred
more frequently with oxychloride I deem it safe to say that an oxy-
chloride has an obtunding effect.
filling
The oxychloride being obtainable whiter than oxyphosphates, is
preferable for lining discolored teeth where the walls are thin. Occa-
sionally it may happen that it is desired to line a wall, and yet there
may be a need to utilize as much of the cavity as possible for the
proper retention of the filling. The thinnest imaginable layer of
oxychloride may be effected by smearing the wall with the fluid and
then blowing the powder against it with a chip-blower. It should be
noted that this is apt to destroy the rubber bulb, because the oxide of
zinc taken within the bulb acts deleteriously upon rubber, causing it to
dry and crack. This may be prevented by careful washing after use.
Oxyphosphate of zinc is invaluable both for permanent and for tem-
As much the manner of
porary purposes. depends upon manipulat-
ing the material, I will explain how best to mix it. According to the
method of mixing, the resulting mass will be either quick or slow set-
ting, and either dense or crumbly.
First, then, as to its setting. The best mixing slab is the side of a
flat glass bottle, which should be provided with a tightly-fitting rubber
In the winter months, with the of the room
stopper. temperature
F., the bottle has no special advantage unless it is desired to
at 70
make the material set either very slowly or very rapidly. If the
bottle be filled with ice-water, the setting will be slow in proportion to
the cold, and vice versa, if filled with hot water, it will be rapid in pro-
portion to the heat. This is more useful in summer, when all have
experienced much inconvenience because of the rapid setting of oxy-
phosphate, so that in warm weather a bottle of ice-water is very useful.