Wife has a total knee replacement and has heard the same story about how it can get infected by just about any other, unrelated, medical procedure.
In her case, and in our area, this seems to be a widely accepted fact and is easily dealt with. Her routine 2 x year dental appointments are always preceded by a single dose of some antibiotic ... not the usual 1-2 week course of antibiotics doctors prescribe for many other things.
It was the surgeon who did her knees who originally told her this, but he is several years in the rear view mirror now ... currently her DDS just calls in the script to our drug store each time, no fuss, no argument.