Instruments, appliances, etc. for crown-, bridge- and metal work : Hollingsworth system of crown- and bridge-work. Various methods of setting Logan crowns / S.S. White Dental Manufacturing Co.

  • S.S. White Dental Manufacturing Company.
Date:
1911
Catalogue details

Licence: In copyright

Credit: Instruments, appliances, etc. for crown-, bridge- and metal work : Hollingsworth system of crown- and bridge-work. Various methods of setting Logan crowns / S.S. White Dental Manufacturing Co. Source: Wellcome Collection.

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

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    DENTAL MFG. CO. [October 1911 Fig. 1 Fig. 2 Fig. 3 Fig. 4 The crown should now be backed up with a disk of platinum, about 36 gage, which should be prop- erly perforated, annealed, and closely burnished to place. In trimming it to follow the outlines of the base of the crown, a slight lingual extension, Fig. 4, f, should be allowed to remain for the purpose of engaging in the investment material, and thus retaining the backing in close proximity with the porcelain during the process of soldering. If this precaution is not observed, the backing will invariably be drawn away from the base of the crown as a result of the shrinkage of the solder, thus diminishing the strength of the union and affording an unhygienic joint. Next warm the post and place a sufficient quantity of Parr's Wax Flux around it as shown by dotted lines, Fig. 4. Replace the Logan Crown on the root (with the cap in position), force home until the labial edges of root and crown meet, obtain the proper alignment, and cool and harden the wax by using a napkin with ice water. Then remove the crown and cap together, held in proper relative position by the wax. (See Fig. 5.) Trim off the surplus wax and invest. (See Fig. 6.) Remove all the wax possible between the crown and the band, and flow 20-karat gold solder into the space. The wax which will neces- sarily remain, being fluxed, will carry the solder into every crevice and give the crown great strength. Finish the band and the soldered edges, and the result will be a strong and perfectly aligned crown. This method of mounting may be used either with or without a band or with a partial band, just as is de- sired. Also this method may be carried out by the cast- ing process, instead of the usual soldering, if desired. If metal parts as described here are made of platinum instead of gold, the crown may be completed by the addition of High-fusing Porcelain instead of gold. In this case, the first disk next to the porcelain tooth is left off entirely. Fig. 5 Fig ' \_ (See Caution about Soldering Logan Crown, page 87) ANOTHER METHOD After preparing the root for receiving the Logan Crown in the usual manner (Fig. A), take an impression of the root and surround- ing parts with the proper quantity of Moldine in a partial impression tray (see illustration). Remove the impression carefully and fill with Melotte Metal. The location of the root canal will be clearly indicated by a small hole in the metallic model (Fig. B), and this hole may be deepened with a twist drill and slotted or elongated for the reception of the crown post with an Ottolengui reamer. This gives a metal root,—the exact counterpart of the natural one and adjacent teeth,—by which the crown may be fitted.