Casting alloys have _____ biocompatibility.

• A. Poor
• B. Good
• C. Variable
• D. Excellent

Answer: (B)

Biocompatibility in this context means how the metal alloy interacts with oral tissues and fluids without causing adverse reactions. Casting alloys are chosen for corrosion resistance and for releasing only tiny amounts of ions under normal intraoral conditions. The protective oxide layers that form on these metals help minimize ion leakage, so tissue responses are typically minimal. Because of this, their biocompatibility is generally good.

There are caveats: some individuals have allergies to nickel or chromium, and galvanic corrosion can increase ion release if different metals contact each other in the mouth. These factors mean biocompatibility isn’t absolute for every person or situation, but overall casting alloys used in dentistry are considered to have good biocompatibility.