There's some bizarre laws regarding this sort of thing, but if I'm not horribly mistaken, this actually rises to one of the attempted 'homicide' (don't recall if its murder or just manslaughter) charges because of the presence of HIV. I may be remembering a different state, but I want to say OK covers any knowing or negligent transmission.
Those laws are pretty common these days, but they are usually written from the standpoint of deliberate or negligent transmission by sexual contact or other deliberate means. The classic charge is you know you have HIV but had unprotected sex with someone and did not inform them of your HIV status. There are also laws that deal with stabbing someone with a syringe or sharps contaminated with HIV.
Some of these laws first came about after the famous case of Dr. David Acer, the Florida dentist who died of HIV in 1990. Six of his patients contracted the same strain of HIV that Dr. Acer had, and there is some suspicion that he deliberately infected patients by some unknown means.
It has been a while since I made a detailed study of these laws, but I suspect that they are not designed to criminalize sloppy sterilization practices or even gross negligence. Courts and legislatures are generally reluctant to criminalize poor results from medical treatment. If you could be charged with murder by having a sick patient die on the OR table, surgeons are going to be pretty reluctant to take those cases.
However, if it can be proven that the dentist knew that the instruments were contaminated with HIV or other pathogens, criminal charges can be a possibility.