The purpose of this study was to compare the effect of different methods of hand washing by counting the number of bacteria on the hand surface. Eighteen clinicians were chosen and divided into three groups, consisting of six clinicians each. Culturing of the right raw palms of all individuals was performed. Individuals in the control group washed hands for 5 seconds with antimicrobial soap. Group 1 washed their hands for 10 seconds with antimicrobial soap. Group 2 washed with an instant alcohol-based hand sanitizer. After the respective washes, re-culturing of the right raw palm was done for each member of all groups. The colony-forming units (CFU) were calculated at each time point, and the reduction rate of CFU among the three groups were statistically evaluated using student t-test. All groups showed a significant decrease in CFU, according to the time applied (P<0.01). In addition, the reduction rate of CFU between the groups were statistically evaluated with ANOVA (P<0.01). It showed statistically difference between the control group and group 1, control group and group 2. The present study confirmed that the hand washing method with antimicrobial soap for 10 seconds and hand sanitizer, including alcohol, were excellent for decreasing the number of bacteria on the hand surface.

• Kyoung-Hwan Yu(Department of Oral & Maxillofacial Surgery, School of Dentistry, Chosun University)
• Mija Kim(Department of Nursing, Daejeon Institute of Science and Technology)
• Hak Kyun Kim(Department of Dentistry, College of Medicine, Chungnam National University) Correspondence