Soldering and remelting influence on fatigue strength of cobalt-chromium alloys.

Abstract

STATEMENT OF PROBLEM:

For laboratory production, it would be economically advisable to reuse excess cobalt-chromium alloys in manufacturing partial denture frameworks. Furthermore, discrepancies in fit, modifications, repairs, and also economic factors could lead to soldering procedure on the metal framework.

PURPOSE:

This study evaluated the influence of soldering and remelting procedures on the fatigue strength of Steldent, Dentorium, and Biosil cobalt-chromium alloys, as new alloys and in a mixture of new and previously casted alloy and when submitted or not submitted to conventional soldering procedure.

MATERIAL AND METHODS:

The soldering procedure was conducted in rod specimens 1.7 mm in diameter made with new, or with a mixture of new and reused alloy (n = 10 per group). The results were compared with those of intact rods. The fatigue strength was carried out with a cyclic testing machine simulating the insertion and the removal of partial dentures. After failure, the fracture surface was examined with a scanning electron microscope.

RESULTS:

The soldered specimens revealed 1119 loading cycles before fracture. These means differed statistically from those of intact alloys, which disclosed 2733 cycles before failure (p < 0.05). Statistical analysis indicated that the soldering procedure reduced fatigue strength of all new alloys or those in a mixture of new and previously casted alloys. It was also found that the soldering procedure may cause premature failure of a removable partial denture. Photomicrographs from fracture surfaces revealed the presence of inclusions and voids. Conversely, there were no significant differences between new and reused specimens, soldered or not (p > 0.05), which suggested that it may be possible to reuse excess cobalt-chromium alloys without compromising the fatigue strength of the framework.

• Authors: G E Henriques, S Consani, J M Rollo, F Andrade e Silva
• Journal: The Journal of prosthetic dentistry (J Prosthet Dent) Vol. 78 Issue 2 Pg. 146-52 (Aug 1997) ISSN: 0022-3913 [Print] United States
• PMID: 9260131 (Publication Type: Journal Article)

Chemical References

• Chromium Alloys
• Dental Casting Investment

Topics

• Chromium Alloys (chemistry, economics)
• Dental Casting Investment (chemistry)
• Dental Restoration Failure
• Dental Soldering (economics)
• Denture Design
• Denture Repair
• Denture, Partial
• Denture, Partial, Removable
• Evaluation Studies as Topic
• Hot Temperature
• Humans
• Materials Testing
• Metallurgy
• Microscopy, Electron, Scanning
• Stress, Mechanical
• Surface Properties