Page 560 - My FlipBook

558 DISCOLORED TEETH AND THEIR TREATMENT.

rent as usual, and the bleaching is very rajiidly effected. Dr. Hol-
lingsworth recommends the addition of about 1 j)er cent, of zinc sulfate
to tlie aqueous pyrozone solution, which not only diminislies the resist-
ance to the ])assa_i>:e of the current, but has a coagiilating effect u])on
the bleached oro-anic matter wiiich gives it translucency and greatly
enhances the permanency of the operation. The results obtained by
this method are extremely satisfactory.

Bleaching Methods for Special Stains.
Pulpless teeth are especially liable to discoloration from external and
accidental causes. If decayed and the cavity has remained unfilled for
a length of time many substances ^vhich find their \vay into the oral
cavity either as food or as medicine may produce discoloration when
absorbed by the tooth through the open cavity walls.
3fefalUe salts are particularly apt to cause such staining by reaction
with the sulfids with which the dentin structure is usually saturated
during decomposition of its organic contents. Many of the medica-
ments used in pulp-canal treatment or even for hypersensitive dentin
may stain the tooth structure, and finally the action of sulfids in the
structure of a pulpless tooth may react with amalgam fillings, forming^
salts of mercury, silver, tin, copper, etc., which are absorbed by the
tooth, resulting in its discoloration. The treatment of these stains,.
which were grouped as Class III. at the beginning of this chapter,,
is extremely difficult and often unsatisfactory. However, there may
arise individual cases of discolorations of this class where it is of the
utmost importance to remove them, and much may often be accom-
plished when the causes of the discoloration are known and the proper
bleaching method is applied.
Gold stains may arise, as has been already indicated, from the inju-
dicious use of gold instruments or failure to remove all gold fillings
when applying some one of the chlorin methods of bleaching. In the
course of time where this has happened the tooth assumes a pinkish
hue which merges into a characteristic violet or purple, finally becom-
ing black.
Iron stains may arise from the use of steel instruments in connection
with the chlorin methods of bleaching or in contact with iodin or any
of the mineral acids in connection with canal treatment. The iron
stain is yellowish at first, gradually becoming brown and finally black.
Copper and nickel stains may arise from contact ^yith these metals
or their alloys, as copper amalgam or nickel or German silver
dowels for artificial crowns or anchorages for fillings. The stains
from these metals are—for copper, bluish to black, and for nickel a
characteristic chlorophyll green which eventually becomes black.