Page 542 - My FlipBook

540 DISCOLORED TEETH AND TlIKIli TREATMENT.

—
Tooth-Bleaching. Use of Chlorin.
Nature of the Problem Involved in Tooth-Bleaching-.—The
bleaching process is (lependeiit upon a elieniical reaction betwecai a com-
pound liavino- color and some substance capal)le of so atrectin(>; its (!om-
j)osition that the color is discharged, or, in other words, of so atfecting
the integrity of the color molecule as to destroy its identity, which
results in a loss of its distinguishing characteristic, viz. its color.
The substances concerned in discoloration of tooth structure, as has
been previously shown, are derived from the pulj) and its vascular
elements and the organic contents of the tubular structure of the dentin,
through the gradual putrefactive processes which become operative
subsequent to the death of the ])ulp. These pigmentary products of
pulp decompositiou we know to be organic in character; and further,
that they exhibit the ])roperty of color by virtue of definite conditions
of molecular composition—that is to say, a certain arrangement of a
definite kind and number of atoms has resulted in the formation of a
molecule having its individual group of chemical and physical prop-
erties, among which latter is a characteristic color.
Whatever brings about an alteration in the composition of the mole-
cule at once destroys the identity of the matter so treated. Hence if
we can act upon the coloring matter which gives rise to the staining of
a tooth by means of an agent capable of effecting an alteration in the
.
atomic arrangement or composition of the color molecule, we may expect
to remove or discharge its color feature.
Two general classes of substances have been successfully used as
bleaching agents : First, those whicli act by virtue of their power to
evolve oxvgen in the active or nascent condition, and known as oxidiz-
ing agents ; second, those which act in an opposite manner by virtue
of their strong affinity for oxygen and which are called reducing agents.
The oxidizing bleachers destroy the identity of the color molecule by
seizing upon its hydrogen element to form water. The reducing agents
act bv removing the oxygen atom from the color molecule to form by-
products depending ui)on the character of the reducing agent used.
Chlorin and its associates iodin and bromin act as indirect oxidizing
b/cachers; the dioxid of hydrogen and of sodium are direct oxidizers.
Potassium permanganate may also be classed with this group, though its
successful use as a bleaching agent depends upon a subsequent treat-
ment of the substance to be bleached with some solvent capal)le of re-
moving the manganese dioxid formed as a by-product of the action of
the permanganate. It has somewhat extensive and satisfiictory use as
an agent for bleaching sponges, and has been used for bleaching teeth,
but is of greatly inferior value to other agents for the latter use.