Page 549 - My FlipBook

TOOTH-BLEACHING— USE OF CHLOBIN. 547

ill the pulp chamber of the tooth. Any acid will effect the liberation of
chlorin from the bleaching powder, but acetic, tartaric, or oxalic are
generally used. Care must be observed in selecting a good quality of
bleaching powder, as that substance rapidly undergoes decomposition
spontaneously, especially in a moist atmosphere. Good chlorinated lime
is a dry powder having a strong odor of chlorin. If it is moist or pasty
aiid has but a feeble odor it should be rejected as worthless. Brands
of bleaching powder dispensed in metallic packages should not be used,
as they are invariably contaminated with metallic chlorids due to the
slow action of the contents upon the containing package. This is par-
ticularly the case where sheet-iron boxes are used. The return of dis-
coloration in many cases after bleaching by the Truman method is
undoubtedly due to the use of bleaching powder so contaminated.
The powder dispensed in glass bottles or in paraffined paper cartons
is more reliable.
Its application to the tooth may be effected in several ways :
(a) By packing the dry powder in the pulp chamber and then moist-
ening the latter with the acid
;
(b) By mixing the powder with sufficient distilled M'ater to make a
coherent mass which is more easily manipulated, then packing it in the
pulp chamber and applying the acid
;
{(') By first moistening the interior of the tooth with the acid, next
dipping the instrument into the powder and then into the acid, each
time carrying the mixed materials into the tooth until the desired
change of color is produced.
Probably the most satisfactory method is to pack the dry powder
into the tooth and apply the acid to it, after which immediately seal the
cavity with a single pellet of gutta-percha. By using a 50 per cent,
solution of acetic acid the evolution of chlorin will take place with a
satisfactory degree of uniformity, and not so rapidly as to interfere with
its penetration throughout the discolored tubular structure of the dentin.
The bleaching mass may be sealed in place by means of oxyphosphate
of zinc if desired, but it is usually unnecessary to use anything other
than gutta-percha or one of the soft temporary stopping materials for
this purpose.
The case may be dismissed for one or two days and the treatment as
outlined repeated at similar intervals until the tooth is restored to
normal color.
The instruments used in connection with this jiroccss should be of
vulcanite, bone, ivory or wood. Upon no consideration should steel,
gold, or platinum instruments be used, as chlorin acts directly upon
each of these metals, forming soluble chlorids which if carried into the
tooth structure will give rise to a permanent staining of most intract-