HIV is not a mandatory test because it is not easily communicable, and also because it is considered a disability under the ADA. There has to be a significant viral load much of the time, it is not airborne, and the virus is actually weakly infectious, even if it is extremely virulent, it isn't nearly as infectious as Hepatitis. Adhering to the universal precaution, and even adding one's own precautions, there is no need that an exposure to be likely, and therefore as a dentist I would definitely protect my right to privacy from the prejudice and ignorance of others. To test for HIV might be good, to ensure treatment, but since there is no vaccine, why make it mandatory?