Mixture or mixture?

At the dentist this morning, where I received an otherwise clean bill of dental health, I learned that one of my old fillings is cracked and will have to be replaced. While discussing it with the hygienist, the dentist asked if it was “amalgam or composite?”

An amalgam is a mixture of substances. So is a composite. So really the dentist was asking, “Mixture or mixture?”

Incidentally, my dentist is the one whose office sounds were recorded by the folks at Pixar for the movie Finding Nemo.