Operative Dentistry. [Volume: 21, Issue: 11, November, 1879, pp. 599-606]

604

THE DENTAL COSMOS.

as that just described; but the root should be prepared and a gold
wire fitted in it in the same manner. A suitable plain " pivot" crown,
having a hole in it a little larger than the gold wire, should be selected and fitted to the surface of the root as perfectly as possible, and
the opening in the porcelain filled with fine, well-seasoned hickorywood, which must then be cut off even with the base of the crown
and a hole drilled in the center and entirely through it large enough
to insert one end of the wire. Insoluble cement may serve the same
purpose as wood. The surface of the wire should be roughened or
finely barbed along its whole length, one end placed (not malleted)
tightly in the opening made for it in the wood in the crown, and the
whole then placed upon the root and finished as above described.
An artificial crown, by whatever method mounted, can be more successfully placed upon a root, and all operations better performed, when
the rubber dam is applied than where it is not used, and it should
therefore be secured, if possible, to the adjoining teeth and then to
the root before the final fitting and mounting of the crown.
Building crowns of gold upon roots of teeth and facing them with
porcelain makes the most permanent operation, although very difficult. After preparing the root, closing the foramen with gold, and
cutting away the irregular or projecting edges to within about a
half-line of the margin of the gum (leaving this much to aid in applying the rubber dam), a gold wire, No. 13 or 14, with a fine, sharp
thread cut upon it, should be accurately fitted in the pulp-chamber
to near the apical foramen. To the platinum pins of the porcelain
selected for the case a cylinder or tube made of gold plate should be
fitted, and, after it is opened as illustrated (a), riveted and then closed,
placed in plaster and fine sand, and
FIa. 6. carefully heated and soldered. A
/( p^ h thread must then be cut in the cylinder corresponding to that upon
the wire to which it is to be ataL, b t tached. This is done that the crown
W ' may be more securely placed upon
the root than by the method described by the writer in the DENTAL
COSMOS, June, 1873. The end of
the gold tube next the cutting edge of the crown may be beveled and
a slot made in the wire at that part, so that the cylinder will be prevented from turning; while still greater strength is added by impacting gold into the open part, thus spreading the end of the wire.
A groove should be cut with a corundum disk in each side (b), and
sometimes along the cutting edge of the porcelain, into which gold
foil is to be placed, to secure greater strength and permanency.