The physical properties of dental amalgams / by the late Thomas B. Hitchcock. The physical properties and pathological action of dental amalgams ; by E.A. Bogue. Read before the New York Odontological Society at the special meeting, December 14th, 15th, 16th, 1874 : and the discussions which followed.

Hitchcock, Thomas Barnes, 1839-1874

Date:: 1875

Credit: The physical properties of dental amalgams / by the late Thomas B. Hitchcock. The physical properties and pathological action of dental amalgams ; by E.A. Bogue. Read before the New York Odontological Society at the special meeting, December 14th, 15th, 16th, 1874 : and the discussions which followed. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

Cover
Title Page
Cover

12/46 page 10

mastication ; and the fact that they do not shrink much, and that they remain siifiBciently soft to be readily removed with an excavator, would make them probably suitable for temporary fillings. By the addition of gold and platinum to silver and tin alloys, we obtain one agent which controls to a great degree the shrinkage, and another which causes the amalgam to harden quickly. Mr. Fletcher, who, as far as I am aware, was the first to suggest the use of an alloy of this kind for amalgams, says that the amalgam called platinum amalgam is composed of the ordinary silver and tin alloy with 10 per cent, fine gold, to which sufficient platinum is added to cause it to set quickly.* When used with a small amount of mercury, it becomes so hard that often at the same sitting of the patient it can be finished with files and burnishers. It moreover keeps its color well. Pallad ium is a metal which is found in platinum ore, and it strongly resembles platinum in color. In very fine powder, as a precipitate, it forms an amalgam, but the two metals require considerable stirring in the mortar to cause them to combine. When the combination has be- gun, the palladium will take up a very large amount of mercury, and unless there is a considerable quantity used, and the amalgam is made very soft, it will harden before it can be placed in the cavity of the tooth. In consequence of the extraordinary rapidity with which it hardens, a large amount of heat is evolved, which is sometimes so great that the mass explodes. This can be avoided, and the amalgam ren- dered much more manageable, by using mercury in which a per cent, of pure gold has first been dissolved. It seems that palladium amalgam has been in use to a limited extent in Europe for many years, and those who have had the most experience with it speak highly of it. As before stated, however, it becomes quite black on the surface ; though I am induced to think that, in those in- stances in which I have used gold with it, the discoloration has not been so great. As it shrinks so slightly, there is no discoloration of the tooth- structure. The plug made by it is extremely hard and brittle. It is a metal which is very difficult to obtain. I found it impossible to pur- chase more than a few dvvts. in this country. By sending to Europe, it can be obtained either as precipitate or plute. The price is very high, costing somewhere in the vicinity of fifty dollars per ounce. When added to a gold, silver, and tin amalgam, it hastens the setting about the same as platinum does. Mr. Fletcherf speaks well of tellurium, which he thinks, either alone or in combination with other metals, would make a good amalgam. The price of this also is very high.

Licence and re-use

Contents