The metallurgy of Ni-Cr alloys for fixed prosthodontics.

Ni-Cr alloys continue to be an important part of dental restorative materials. It behooves those interested to study these alloys and develop an understanding of their chemical and physical characteristics. Introduction of new alloys almost monthly presents an educational challenge to the entire profession. Many dental schools do not use Ni-Cr alloys for fixed prosthodontics because questions exist about the efficacy and performance of such alloys. These doubts may be resolved by continued research. Concern about mechanical properties can be alleviated if an understanding of the requirements for successful use, for example, casting, burnishing, polishing, and stresses encountered in service, is achieved. Information on the nature of corrosion intraorally is needed, particularly with regard to correlating in vitro testing with in vivo performance. Further studies of porcelain-alloy compatibility are indicated to understand properties affecting compatibility. Performance of high-temperature porcelain-alloy systems could influence processing techniques so that specific materials could be used more appropriately. In addition, the nature of porcelain-to-alloy bonding may be revealed by use of advanced chemical analysis techniques to identify processes occurring at the atomic level, with identification of oxides and reacted zone produces may also provide data for design of new alloys for porcelain-metal systems. Finally, factors related to the clinical performance of nickel-based alloys, including their allergenic potential, have not been considered in this report.