Dental instruments and devices require sterilization or high-level disinfection. An evaluation of the implementation of such processes was undertaken. Eleven thousand questionnaires on methods used to sterilize and disinfect dental instruments were sent to dental practices and 1391 (13%) were returned for evaluation. Sixty-eight percent of respondents believed they were sterilizing their instruments, however, some of the liquid chemical products used were not suitable for sterilizing instruments, and 12% of respondents used incorrect contact times. Forty-nine percent of respondents did not challenge autoclaves with biological spores to check their function at an acceptable frequency. There were similar product and timing problems when a high-level liquid chemical disinfection was attempted. Although the return sample was small, problems were identified that can and should be corrected. This study demonstrates that the potential for person-to-person transmission of infectious agents such as the human immunodeficiency virus (HIV) and hepatitis B and C viruses via inadequately sterilized dental instrument exists depending on the prevalence of HIV in the dental practice area.