Volume 3

The principles and practice of dentistry : including anatomy, physiology, pathology, therapeutics, dental surgery and mechanism / by Chapin A. Harris.

  • Harris, Chapin A. (Chapin Aaron), 1806-1860.
Date:
1898
Catalogue details

Licence: Public Domain Mark

Credit: The principles and practice of dentistry : including anatomy, physiology, pathology, therapeutics, dental surgery and mechanism / by Chapin A. Harris. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

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    5 parts; tin, i part. He claims that such a Babbitt alloy for the die cannot be excelled. Dr. C. J. Essig recommends zinc for a counter-die for swaging a plate of platinum-gold or iridium-platinum ; and also that such a counter-die is of especial service in partial cases where a number of teeth remain. For difficult swaging he recommends three sets of dies and counter-dies, the most imperfect of the dies being furnished with a lead counter-die, to be first used, and the next in quality to be used with a zinc counter-die, and the nearest perfect of all with a lead counter-die as a finishing die. SWAGING. A die and counter-die having been obtained, a piece of tin foil or sheet lead is adapted to the former, and the dimensions of the plate marked upon it. Paper is sometimes used for this purpose, but is not so good as thin sheet lead or heavy tin foil. The pattern thus made is cut out, flattened, and laid upon the gold plate, and its out- line marked upon it. The outline of the plate may be marked on the plaster model and the pattern cut in conformity therewith. The margins of the plate for the upper jaw should extend as high as pos- sible, and especially over the position of the canine teeth, in order to restore the expression, which is greatly changed by the loss of the natural teeth at such points; back of the canine teeth the margin of the plate should be lowered so as to avoid the attachment of the muscles and to allow the latter free motion or action. The plate should also embrace the maxillary tuberosities in order to obtain stability, and the margins at such points may extend higher than over the bicuspids and first molars. The plate should be cut a little too large, to allow for trimming and any accidental slipping upon the die. In partial cases the pattern should be carried partly, or fully, over the excised teeth, and no attempt made to fit it accurately around the necks of the teeth until the swaging is nearly or quite completed. With a pair of strong shears the portion of plate thus marked is cut out. Fig. 956 represents a pair of shears, with long and conveniently-shaped handles. The blades of some shears are curved laterally; but this form is not desirable. A fine watch spring saw, Fig. 613 (p. 679), should be used for curves which the straight shears will not cut ; curved shears may also be used for such a purpose ; for very short curves—around teeth, for instance—a pair of cutting for- ceps will be found useful.