Artificial Teeth.—The progress of modern dentistry is nowhere more apparent than in the cheapness and perfection with which lost teeth can be replaced. Sometimes when the crown of the tooth is broken, it can be covered with an artificial crown, and the loss of one or more teeth can sometimes be repaired by a bridge consisting of several crowns anchored to two or three adjacent roots. All lost teeth, whether in the front or back part of the mouth, should be, on the ground of health, replaced at the earliest possible moment. Artificial teeth should be kept perfectly clean. And plates should be removed at night and placed in an antiseptic so lution, such as listerine or boric acid.
Temporary Filling for Teeth. — First cleanse the cavity by using a bit of cotton at the end of a tooth pick. Dip this in an antiseptic solu tion, as boric acid in water. Rinse out the cavity with the same, or IA solution of peroxide of hydrogen, by means of a small glass or rubber syringe. Drop a small piece of gutta-percha into boiling water. Cut off with a penknife sufficient to fill the cavity and press it in the tooth with an orange stick or a piece of soft pine wood whittled to conveni ent size and shape. After filling the cavity, remove carefully any gutta percha that may adhere to the out side of the tooth; and fill the mouth with cold water several times until the gutta-percha hardens.
Or melt a small piece of gutta percha at the end of a wire by mois tening in boiling water or holding over If hot stove or other heated sur face, and insert while warm.
Dentists' Amalgam for Filling Teeth.—Gold, 1 part, mercury, 8 parts, melted together with gentle heat and poured while melted into cold water.
Or dissolve 21. parts of powdered mastic in 1 part of ether and mix to a stiff paste with powdered alum.
Or melt together equal quantities of tin foil and mercury and when cold enough to bear the hands, knead a small quantity with the fingers and insert quickly- before it hardens.
Or melt together 1 part of cad mium, 2 parts of tin. Allow the re sulting alloy to harden, reduce to filings and add sufficient mercury with gentle heat to make a fluid amalgam. Squeeze out any excess of mercury through leather. Knead up the solid remnant with the fingers and fill the cavity with this.
Or make a fluid amalgam of either gold or silver with mercury. Squeeze out the excess of mercury through leather and use the residue.
Or for a quick, cheap, and handy amalgam, mix when required for use 20 grains of fine zinc filings, 40 grains of mercury.
Or amalgamate with quicksilver 6 parts of zinc, 21 parts of tin, 73 parts of silver.
Or melt together 1 part of pow dered gold, 3 parts of silver; add 2 parts of tin, allow to cool and harden; reduce to fine filings and mix with an equal quantity of pure mercury when required for use.
Or make into a paste with equal parts of quickly drying copal and mastic varnish 1 part of gypsum, 1 part of powdered porcelain, 1 part of iron filings.
Or amalgamate 2 parts of steel filings with 4 parts of quicksilver.
Dentists' Nerve Paste.—The sub stance used by dentists to kill the nerve is arsenic in very minute quan tities.
Mix 1 part of arsenic with 2 parts of rose pink and apply on a bit of cotton moistened with creosote. Re move after 3 or 4 hours and wash out the cavity with water containing an antiseptic, as boric acid.
Mix 15 grains of arsenious acid and 10 grains of sulphate of morphia with creosote to a paste, and apply on cotton; but this should never be done without having the nerve immedi ately removed by a competent den tist. Otherwise the nerve pulp in the roots of the tooth will decay and will form an ulcer, which will work through the gum and sometimes through the face and continue to dis charge until properly treated. Hence work of this sort should be intrusted only to a competent dentist.