Page 123 - My FlipBook

MAKING AND SETTING OF A GOLD INLAY 119

Many times an onlay can be flowed to the desired thickness in
much less time than that required to invest and cast.
Making the Matrix. This is done in the same way as though a
greater bulk of gold were to be added. Such inlays must be re-
tained by one or more pins soldered to the cavity side as pre-
viously described.
The matrix is burnished to perfect fit and the outline definitely
established. The matrix should be trimmed to within about one-
fourth millimeter of the cavity outline and reburnished and care-
fully removed.
The matrix is then given a coat of whiting on all that portion
Avhich is to come in contact with the tooth to prevent the solder
from flowing on that surface.
Sweating the Contour. The gold matrix should be then laid
upon the soldering block and Avith a brush flame from the bloAV
pipe 22K plate or 22K solder fused to the thickness desired in the
various locations on the matrix. When a sufficient amount has
been fused in any portion, that part of the surface should receive a
coat of whiting.
Gold can then be fused to still exposed surface without its
spreading to portions where it is not wanted. By this means it is
possible to build up a given portion of the inlay, even to the add-
ing of cusps to occlusal surfaces.
Method of Using Sponge Gold as a Pattern. Take the sponge
gold as bought on the market for making a cohesive gold fillinjr
and saturate it with any casting Avax on the market. This is best
accomplished by dipping a sufficient amount of the heated gold,
while held in the pliers, into the molten Avax, and immediately re-
moving to a clean surface to cool. Remove any excess Avax.
Making the Pattern. AVhen this method is used any undercuts
in the cavity should be filled with cement. A portion of the satu-
rated gold large enough to a little more than fill the cavity is
grasped between the pliers and slightly Avarmed and carried to the
cavity and croAvded to position and the contour determined in
much the same Avay as amalgam is manipulated. A matrix should
be used in class tAvo cavities, but not sufficiently high to prevent
occluding the teeth. When the pattern has the desired contour
form, the Avhole is remoA-ed the same as described for removing a
pattern composed of Avax alone.
Investing. A sprue of Avax is attached to the usual place as
though the casting method Avere to be used. The pattern is then