Page 510 - My FlipBook

508 DENTAL MEDICINE.
ing agent for carious and discolored dentine. For bleaching pur-
poses, Dr. Kirk recommends saturating the dentine with a strong
solution of peroxide of sodium (50 per cent.), following this by
treatment with a dilute acid, such as hydrochloric, sulphuric or
acetic, or a ten per cent, solution of trichloracetic acid ; the pref-
erence is given to hydrochloric. In addition to such properties,
peroxide of sodium completely sterilizes the dentine by acting as
a mechanical cleanser, and a solvent of the organic debris and
fats, in the form of small shreds of pulp-tissue and organic matter
in a partially decomposed state. Dr. Kirk also recommends,
after the application of the peroxide of sodium, inserting into the
canals, for a moment on cotton, a diluted solution of hydrochloric
or sulphuric acid, afterward washing and drying with hot air,
and then immediately filling them. For the upper teeth he
recommends that the application of the solutions be in pledgets
of asbestos fibre, as the cotton is rapidly disintegrated by strong
solutions.
Dr. Harold Clark describes his method of preparing a saturated
solution of peroxide of sodium as follows :
" I put two ounces of distilled water in a small four ounce
lemonade glass and prop it up in a basin of water so that the level
of the water in the glass be just below the level of the rim of the
basin. I place the latter under the cold water tap so that a small
stream may run continuously into the basin about the glass. In
this way its contents are prevented from rising in temperature.
The violent reaction occurring when peroxide of sodium is put in
water, raises the temperature of the water, driving off^ the oxygen
which we desire to retain in the solution. By surrounding the
glass with cold water and sifting the peroxide of sodium in small
quantities every half hour until the solution becomes semi-
opaque we obtain in the course of two or three days a saturated
solution."
Dr. L. P. Van Woert suggests the following method of pre-
paring a satisfactory solution of peroxide of sodium : "Take a
common tumbler about half full of distilled water, place it in the
centre of a good-sized pudding-dish, and pour all the cold water
around it possible, without floating the glass. Add the sodium