Observations on nickel-free, beryllium-free alloys for fixed prostheses.

Mechanical properties, electrochemical behavior, heat treatment response, micro-structural features, and compositions of two proprietary nickel-free, beryllium-free fixed prosthodontic alloys were studied. The alloys showed compositional and microstructural differences. Mechanical property values of Biocast and Neobond II are comparable with those of base metal alloys for removable partial dentures. The high hardness, high modulus of elasticity, and low elongation impede adjustment, adaptation of margins, and polishing of the final restoration.