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CROWX- AND BRIDGE-WORK. 177

ciently to clam]) tlie posts, inserting throUL;'!! the open face
of the crown, as shown in Fig. 145, solder and finisli as
before.
THE DOWNIE CROWN.
In this crown we ha\e a combination of the all-porcelain
crown with a l^and or ferrnle. The root is prepared and
measurement taken as has just been described for the
Richmond crown.
Making the Band.—The band is made from platinum, a
strip of which of sufficient length and width is soldered
with pure gold. The band is now adjusted and fitted to
the root, allowing a narrow margin to extend below its end.
Remove the band and cut small V-shaped spaces in its lower
border, which, when the band is replaced in position, will
allow the points to be bent down over the root. Fig. 146
shows the band thus prepared.
Preparing the Tooth.— Select a suitable plain, cross-pin
tooth, take square iridio-platinum wire of sufficient size for
post, taper one end and flatten the other with a hammer,
file notch in each side, and, placing between pins, bend them
over as in Fig. 147. If the bite is close,
^'^'^' '"^ '"^^^
grind pins down to give sufficient room for '
the body. After fitting the tooth to posi-
tion, by bending post, if necessary, or grind-
ing base of tooth, dry the root and adjacent
parts, and warming a small pellet of sticky
wax, place it on end of band, which is in
position on the root, and force post through it and press
tooth up to position. Now bring wax up against the back
of the tooth and see that the articulation is correct. Care-
fully remove all together by loosening band with hoe-shaped
exca\^ator. Remove wax from around post where it has
drawn inside of the band. Mix silex and plaster, in the