Page 300 - My FlipBook

298 TlIK OPERATION OF FILLINO CAVITIKS.

of the filling. Those made of fine cornnrlnm and shellac, or corundum
and vuhranized rubber, are more desirable than the coarse ones, which
Fig. 263.

('uruniluin ixiints.
are liable to grind away the cavity margins because of the ra})idity with
which they cut.
Fig. 264.
W'^ n™

llindostau points.
Fillings upon labial and buccal surfaces ; >houl(l be dressed down
with fine corundum points or the Hindostan
Fig. 265.
stones shown in Fig. 264 until the outline of
the cavity has been reached. Any overlap-
ping of the gold upon these surfaces gives a
ragged appearance to the filling and detracts p^ v.^^
much from its beauty. Care should also be Felt polishing wheels.
exercised in giving the filling the same degree
Fig. 266.
of convexity that the tooth formerly had ; in
other words, the filling should accurately re-
store the lost anatomical contour of the tooth.
When sufficient gold has been removed the
surface should be nicely smoothed with re-
volving w^ood points charged with pumice
powder and water, or a paste made of ])umice
and crlvcerin, after which the final finish mav
be made with flour of pumice, chalk, or oxid
of tin, used by means of a revolving disk or
wheel of felt or soft rubber (Fig. 265). The
soft rubber polishing cup of Dr. John B.
Wood is a valuable aid in polit^hing the con-
vex surfaces of ap])roximal fillings or those
upon the cervical portion of labial cavities.
Dr. Wood's polishing cup.
It is shown in Fig. 266. As fillings upon the
labial surface are more or less conspicu(^us at best, it is better not to
give them a burnished surface. The dead or satin-like finish which is
left by the flour of pumice is usually j^referred.