If dental assistant puts hands on her chair with each patient, can hcv be spread(she handles all utensils)?is her chair usually cleaned between pt's?

Rare: Dental offices and all other medical facilities must practice the same infection control standards developed by the cdc. All surfaces in the treatment room are supposed to be disinfected with a high level disinfectant that can kill hcv, hbv, hiv, tb, and all other pathogenic microbes. All non-disposable instruments need to be cleaned and sterilized in sealed packets as well. You needn't worry.

Highly doubtful: Everything in the room that was used is sterilized or replaced. It would be highly unlikely for an infection to spread between patients.