Home Subscription Services
 
   

 
The International Journal of Prosthodontics
IJP Home Page
About the Editor
Editorial Board
Accepted Manuscripts
Submit
Author Guidelines
Submission Form
Reprints / Articles
Permissions
Advertising
MEDLINE Search
 
 
 
 
 
FacebookTwitterYouTube
Quintessence Publishing: Journals: IJP
The International Journal of Prosthodontics

Edited by George A. Zarb, BChD, DDS, MS, MS, FRCD(C)

ISSN 0893-2174

Publication:
November/December 2003
Volume 16 , Issue 6

Back
Share Abstract:

Effects of Local Cooling Rate and Processing Variables on Leucite in Dental Porcelain

J. Rodway Mackert, Jr, DMD, PhD/Geoffrey W. Sheen, DDS, MS/Amalia L. Williams, BS/Carl M. Russell, DMD, PhD/Janet W. Ergle

Pages: 647–652
PMID: 14714846

Purpose: This research determined whether there is a measurable effect of local geometry factors on leucite content of dental porcelain in fixed partial dentures (FPD). Materials and Methods: Four-unit FPD frameworks (n = 36) were fabricated using a nickel-chromium alloy (Rexillium III). Body porcelain (Crystar, shade A2) was applied in one increment and subjected to two simulated body firings, followed by a simulated glaze firing to achieve a thickness of 1.5 to 2.0 mm. The completed FPD specimens were randomly assigned to three groups of 12 specimens each: (1)simulated post-soldering, (2)multiple firing, and (3) control. The FPDs from each test group were sectioned into individual units: canine retainer, premolar pontic, molar pontic, and molar retainer. The porcelain was removed from each unit, and the leucite content was measured via quantitative x-ray diffraction. Results: Porcelain cracking indicated that the soldering simulation had successfully reproduced conditions in the dental laboratory that result in porcelain cracking during soldering. The leucite content was not significantly different between the retainer and pontic units for either the soldering simulation or control FPDs, although the canine retainer units did have a slightly lower leucite content than the pooled values of the other units. Comparison of the pooled data for the three groups indicated statistically significant differences among the leucite contents. Conclusion: Compared to the control, the simulated post-soldering procedure produced a significant increase in leucite, and the multiple firing group exhibited a significant decrease in leucite. Increases in leucite weight fraction during post-soldering operations—and the larger thermally induced stresses that accompany these leucite increases—are responsible for the cracking that occurs. Int J Prosthodont 2003;16:647–652.

Full Text PDF File | Order Article

 

 
Get Adobe Reader
Adobe Acrobat Reader is required to view PDF files. This is a free program available from the Adobe web site.
Follow the download directions on the Adobe web site to get your copy of Adobe Acrobat Reader.
  © 2014 Quintessence Publishing Co Inc
 

Home | Subscription Services | Books | Journals | Multimedia | Events | Blog
Terms of Use | Privacy Policy | About Us | Contact Us | Advertising | Help | Sitemap | Catalog