7. (Ostermaier’s Cement.) Mix 12 parts of dry phosphoric acid with 13 of pure and pulverised quicklime. It becomes moist in mixing, in which state it is introduced into the cavity of the tooth, where it quickly becomes hard. [In some hands this has failed, from what cause we are not aware.] The acid should be prepared as directed under Acid, Phosphoric.
8. (Silica.) This name has been given to a mixture of Paris plaster, levigated porcelain, iron filings, and dregs of tincture of mastic, ground together.
9. (Wirih’s Cement.) It is said to consist of a viscid alcoholic solution of resins, with powdered asbestos.
10. (Metallic Cement.) Amalgams for the teeth are made with gold or silver, and quicksilver, the excess of the latter being squeezed out, and the stiff amalgam used warm. Inferior kinds are made with quicksilver and tin, or zinc. A popular nostrum of this kind is said to consist of 40 gr. of quicksilver and 20 of fine zinc filings, mixed at the time of using. Mr Evans states that pure tin, with a small portion of cadmium, and sufficient quicksilver, forms the most lasting and least objectionable amalgam. The following is the formula:—Melt 2 parts of tin with 1 of cadmium, run it into ingots, and reduce it to filings. Form these into a fluid amalgam with mercury, and squeeze out the excess of mercury through leather. Work up the solid residue in the hand, and press it into the tooth. Or, melt some beeswax in a pipkin over the fire, throw in 5 parts of cadmium, and, when melted, add 7 or 8 parts of tin in small pieces; pour the melted metals into an iron or wooden box, and shake them till cold, so as to obtain the alloy in a powder. This is mixed with 21⁄2 or 3 times its weight of quicksilver in the palm of the hand, and used as above.
Another cement consists of about 73 parts of silver, 21 of tin, and 6 of zinc, amalgamated with quicksilver. An amalgam of copper is said to be sometimes used. But this class of stoppings is altogether disapproved of by other authorities. Pure leaf-gold seems the least objectionable.
11. (Marmoratum.) Finely levigated glass, mixed with tin amalgam.
12. (Poudre Metallique.) The article sold under this name in Paris appears to be an amalgam of silver, mercury, and ammonium, with an excess of mercury, which is pressed out before using it.
13. (Fusible Metal.) Melt together 8 parts of bismuth, 5 of lead, 3 of tin, and 11⁄2 or 1·6 of quicksilver, with as little heat as possible. (Chaudet.)
14. (Non-expensive Metallic Tooth-stopping.) Take 1 part of sulphate of mercury, 1 part of copper in fine powder; rub them well together with a little warm water; when the amalgam is formed wash well, and remove the surplus of mercury by pressing it through chamois.—Pharm. Journ.
Expensive Metallic Tooth-stopping and much preferable. Take pure gold, pure gelatin, 1 part of each; pure silver, 2 parts; melt, and when refrigerated, reduce to a powder by means of a file; wash well and dry. In the moment of using it add sufficient mercury to form a plastic paste.—Pharm. Journ.