Fig. 3

Colony counts before and after disinfection of chlorine dioxide and organochlorine disinfectants. (a) and (b) show the colony counts in the waterlines before and after disinfection for high-speed handpieces and three ways syringes, respectively. (c) (d) and (e) show the colony counts immediately post-disinfection, three days post-disinfection and one week post-disinfection, respectively. The dotted line stands the contamination line, over which indicates contamination. Dio and org are chlorine dioxide disinfectant and organochlorine disinfectant, respectively. Paired T-tests were conducted. *P<0.05, **P<0.01, ***P<0.001.