Page 258 - My FlipBook

242 THE TREATMENT OF TEETH
main cavity with the acid is undesirable. The use
of aqua regia (nitro-hydrochloric acid) has been
recommended in preference to sulphuric acid for
this reason by Dr. F. T. Hayes [Dental Cosmos, De-
cember 1900). Aqua regia can be carried to a
cavity by means of cotton-wool wrapped round
a fine probe, for it does not destroy the wool, and
consequently it can be more easily worked into a
canal. It appears to act quite as well as sulphuric
acid. These acids are potent germicides, and one
may be tempted to use them for this purpose.
Their use, followed by the neutralising effect of
bicarbonate of soda, has been recommended as
a ready and efficient means of cleaning all root
canals. It must, however, be borne in mind that
they are very irritating, and that a thorough
cleansing of all kinds and sizes of canals by their
means is likely to cause considerable irritation in
many cases. Used for the opening up and pene-
tration of very tine canals they are often indispen-
sable, and they have also great value in enabling a
closed apex to be often opened without resorting to
the dangerous drill. In cases of blind abscess,
when the finest steel bristle cannot be made to pass
through the foramen, the use of these acids in con-
nection with the bristles will often enable the apex
to be opened and the pus to escape, to the great