Cross-contamination potential with dental equipment.
Some types of reused dental equipment, especially handpieces and their attachments for drilling and cleaning teeth, might be responsible for cross-contamination if patient material were to lodge temporarily in difficult-to-disinfect internal mechanisms. This possibility is worrisome with respect to transmission of hepatitis B and human immunodeficiency viruses (HBV, HIV). Previous cross-contamination studies have relied on laboratory experiments with bacteria or dye tracers. To assess possible risk more thoroughly, we tested 30 new prophylaxis angles and 12 new high-speed handpieces to see whether they would take up and expel contaminants in laboratory and clinical trials. In treatments of three patients, including two infected with HIV, human-specific DNA (beta-globin, HLA DQ alpha) and HIV proviral DNA were detected inside or coming back from the devices. Similarly, when handpieces were operated in contact with blood pooled from HBV-infected patients, HBV DNA was detected in samples taken from inside the equipment and from their attached air/water hoses. When we used bacteriophage phi X174 as a model virus in laboratory tests, many infective viral particles were recovered from internal mechanisms of handpieces, their connecting air/water hoses, and from water spray expelled when the equipment was reused. We recommend that reused high-speed, air-driven handpieces and prophylaxis angles should be cleaned and heat-treated between patients. Further studies are needed to determine ways of eliminating the risks associated with exhaust hoses and air/water input lines.
Faculty of Ecology, University of Georgia, Athens 30602.
D L
DL
Lewis
M
M
Arens
S S
SS
Appleton
K
K
Nakashima
J
J
Ryu
R K
RK
Boe
J B
JB
Patrick
D T
DT
Watanabe
M
M
Suzuki
D001435:Bacteriophages; D003428:Cross Infection / Q000635:transmission; D004247:DNA / Q000032:analysis; D004279:DNA, Viral / Q000032:analysis; D003748:Dental Equipment; D004866:Equipment Contamination; D015658:HIV Infections / Q000235:genetics / Q000635:transmission; D006509:Hepatitis B / Q000235:genetics / Q000635:transmission; D006801:Humans; D017053:Infection Control
D004279:DNA, Viral; D004247:DNA