Principles and practice of filling teeth / by C.N. Johnson.

  • Johnson, Charles Nelson, 1860-1938.
Date:
1902
Catalogue details

Licence: Public Domain Mark

Credit: Principles and practice of filling teeth / by C.N. Johnson. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

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    of the various alloys, he was finally enabled to produce one which would neither shrink nor expand, and which would sustain suffi- cient stress to make it reasonably serviceable in the mouth. But the conditions surrounding the manufacture and manipulation of such an alloy are so intricate and so exacting, and the ingredients so sensitive to the slightest variation in temperature or in treat ment, that to produce a uniform product from one time to another would seem to be well-nigh beyond the possibility of human attain- ment. Manufacturers find that an ingot melted from a given formula may give a certain result, while another ingot from the same formula, and apparently treated in the same way, will show a variation in the result. The closest attention to the minutige is, therefore, necessary all along the line, from the refining of the original metals down to the filing and annealing of the finished product. Even then no one batch of alloy should ever be sent out short of a final test of the amalgam made from it by the most delicate machinery; and, in passing, it may be stated that when these tests are made they frequently prove a source of discourage- ment to the conscientious manufacturer. Discrepancies arise at every hand where, apparently, the greatest care had been taken with the preparation, and the more this amalgam question is studied, the more it Avould seem to be hedged about by limitations so great as to be disheartening in view of the immense amount of the material being used at the present day. It would probably be better for the' profession and the public if much of the energy which is now being expended on amalgam were diverted to other materials which are capable of more definite and uniform results. And yet amalgam under existing conditions cannot well be ex- cluded from our present list of filling-materials. It has been too useful for certain purposes, even with its limitations, to be entirely discarded. Its chief utility relates to the building up of teeth so badly broken down or so remotely situated in the mouth as to ren- der the use of gold too exacting, and also to the saving of teeth whose peridental membranes are so impaired as to preclude the use of the mallet. Employed with discriminating care, amalgam may, under these conditions, serve a useful purpose; but it can never