Strength, hardness, corrosion evaluation and computer-aided designing of cobalt-chromium molybdenum maxillary major connectors (Part I)‎

Abstract EN

Rigidity is one of the main criteria for the major connector.

This study was conducted to determine the effect of width and thickness on the rigidity of single palatal strap major connector using two cobalt–chromium molybdenum (Co–Cr–Mo) alloys, Remanium and Biosil cast by two different techniques, electrical induction–melting, and gas–oxygen torch melting on the transverse strength of maxillary major connectors.

Materials and methods: Forty–eight specimens for transverse strength, twenty–four specimens for hardness, and twenty–four specimens for corrosion were prepared, examined by x–ray then tested by engineering test equipment, hardness tester, and sensitive electronic balance respectively.

Ion release into saliva was tested by Atomic Absorption Spectrophotometer and chemical methods.

Results: There was a statistically significant effect of each of the products, casting techniques, width (4&8)mm and thickness (0.4&0.6)mm on the transverse strength of Co–Cr–Mo single palatal strap major connector and statistically significant effect of each of products and casting techniques on hardness of Co–Cr–Mo alloy, but results of corrosion and ion release tests were insignificant.

Conclusions: The major connector made from Remanium cast by induction technique produces stronger and harder specimens.

The effect of thickness is more significant than the width, and there was no significant change in weight after 760 hours immersion in saliva