OBJECTIVE: To determine whether there were any recent changes in hepatitis B immunisation of dental staff, infection control or understanding of viral infections in Brazilian dentists.DESIGN: A randomised survey was conducted on 740 dentists attending the National Dental Congress in Sao Paulo, Brazil in 1994.SUBJECTS AND METHODS: The 740 dentists were questioned as to the presence of various viruses in saliva, the perceived risks of dental staff and long‐term sequelae, the availability and uptake of vaccines, willingness to treat virus‐infected persons, and means of infection control. Nearly 69% of respondents were female dentists, of mean age 30 years. Results were compared with a similar survey from 1990.RESULTS: Most respondents knew that HIV and hepatitis viruses could appear in saliva and almost all knew of infective risks from hepatitis B (HBV), and the availability of the vaccine. Less than half knew of the association of HBV with liver cancer. There was a four‐fold increase in those vaccinated against HBV since the low figure of 9% in 1990. Nearly two‐thirds of respondents perceived an occupational risk to dental staff from HIV, and a similar proportion were also unwilling to treat virus‐infected persons. A similar proportion also used chemical disinfection for some dental instruments.CONCLUSIONS: The results show little improvement over a 4‐year period except a much greater proportion of dentists were immunised against HBV. However, still only one third of dentists had been vaccinated, in a country with a high prevalence of infection in the general