The sun., 1907-08-11
MAKING a PORCEIAIN INLtI.
Interesting Processes OF an Operation In
Modern Dentistry.

This was an upper front tooth that hal
once been filed with gold, but fresh decay
having set in around that filling II had be-
come necessary to I'LL the tooth again. This
time. the dentist said, he thought he would
fill il with porcelain.
All the processes Of making porcelain
inlay are interesting. Having drilled the
cavity in the tooth to its required depth and
shape. the dentist next proceeds 20 max"
a matrix or mould OF it in gold foil, whicI
he il enabled to do without breaking this
delicate material by the use Of hit Of
sponge between it and the crowding tool
So he crowds the gold foil down around
within it everywhere to fit into the cavity
perfectly, and getting the depth all around
the edge OF the mould so exactly that the
inlay to be made in il, when set into place.
will not only fit perfectly in the cavity. hrt
fit into IL with its edges flush all around with
the surrounding surface Of the tooth.
The mould thus made of the cavity in tho
tooth may look like the tiniest OF tiny gold
cups, or it may have some irregular shape,
according to the shape Of the cavity, but.
whatever its shape this mold OF gold foil is
40 slight and thin that a touch would crush II,
and IL seems indeed as II a breath would
blow it away, as probably u would. AMI
celain can ever be formed in mould so frail
and delicate: but it is all really very simple,
as you will see.
Now the dentist takes n small metallic
holder about the size and shape OF very
small clam shell, which he fills with pow
dered asbestos mixed with water, and on
top Of this yielding material, handling 1t
gently with a pair OF pliers, he sets the
delicate little gold mould, with its closed
end down. resting so on the surface OF the
rnoistened powdered asbestos; This holder
has lip on one side Of its edge, by which
il can be lifted with pair OF pliers made
for the purpose and serving thus as
handle for it.
Lifting the little SAUCER now by this
handle this operator rubs on the handle
bow very gently back and forth on the
strings OF a fiddle; lead pencil might do
for this, but he il likely to Use some pro-
fessional tool with a chased or engraved
handle, whose Irregularities will heighten
the effect; and rubbing gently with this
on the handle of the holder he commu-
nicates to 1t and to it's contents and 70 the
little gold mould on top continuous. gentle
vibrations which, slight al they are still
cause the mould gradually 70 settle and
embed itself in the semi-fuid mass N the
holder. and this without in the slightest
changing its shape. These vibrations are
continued till the mould has settled 10 the
required depth. and then the water u
evaporated from the asbestos, and there
you have che little gold mould firmly IN,
bedded in practically solid material ana
ready for use.
The inlay will be made in the mould from
a porcelain powder. Porcelain powders
for dental use are made by the manu-
factirers Of dental supplies in endless
variety of shades. so that il IL easily pos
sible TO get powder whose finished product
will match any tooth. The dentist has
great assortment of teeth made from
porcelain powders. these all named or
numbered. and he matches up your tooth
with one of these and uses for the inlay
the powder Of the corresponding number
With the little gold mould all ready ihe
operator now mixes sufficient quantiy
OF the porcelain powder with alcohol Z"
give him the material in a plastic form
while at the same time the alcohol WI
evaporate quickly. He vets also the
asbestos in the mould holder. TO keep that
from absorbing the alcohol in the porcelain
powder.
And now with his porcelain in workable
form he fills the mould with il. 10 make
there the shape that is 10 be SET into the
tooth. and then he proceeds to fashion
in the plastic material its outward part;
This may be simply slightly rounded
surface. for an inlay that is 10 go into the
Halter part of "a tooth. or the inlay may
both; but whatever the outward part may
be the operator 80 moulds and fashions
that il will continue and complete naturally
the contour OF the tooth into which the
inlay is TO be set.
With the modelling thus finished 'he
inlay il ready for the final process ana
now, with the holder. mould and all 4 g
put into tiny electric oven, ont of which
after suitable time it is taken, haNed
into solid bit Of porcelain, the inlay com
pleted.
II is set in place with cement; and 50
perfectly ia porcelain inlaying nov done
that except upon the closest inspection
II may be- impossible TO tell in an lnlaiii
where the inlay begins; a nice operation
in modern dentistry.