Dental operator having highest risk of infection from:

HBV is very highly infectious, far more that HIV. Any object or procedure than can convey minute traces of infected blood or other material, as little as 0.00001 ml, can be infectious. These include shared  syringes, needles and other sharp items or endoscopes, personal articles such as razors, nail clippers or combs, and practices such as acupuncture, tattooing, ritual circumcision, ear  or  nose  piercing,  and  field  camps  for  surgery or disease detection by blood testing where separate sterile articles may not  be  available. Professionals using sharp articles like barbers, dentists and doctors may unwittingly transmit the virus if great care is not taken. Reference: Ananthanarayan Microbiology  8th edition page no  550