Clinical Study Of The Disinfection Effect On Dental Unit Waterlines By Different Methods

Purposes The purpose of this study is to compare the disinfection effect of O3, sodium hypochlorite, hydrogen peroxide, hydrogen peroxide silver ion on dental unit waterlines (DUWLs), including high-speed handpiece, triple syringes and mouthwash. To analyze the disinfection effect of three concentrations of hydrogen peroxide silver ion (2.5%,5%,10%) on dental unit waterlines, including high-speed handpiece,triple syringes and mouthwash. Try to find the suitable disinfectant and its best concentration for dental unit waterlines.Methods (1) Dental units were divided into O3 group (2mg/L), sodium hypochlorite group (500mg/L), hydrogen peroxide group (30g/L), hydrogen peroxide silver ion group (5%) and control group. The use years, daily treatment of Dental units among each group were compared. Take the United States Center for Disease Control and Prevention (CDC) (<500CFU/ml)、American Dental Association (ADA) (<200CFU/ml)、drinking water criterion (<100CFU/ml) for standard, we compared the detection rates of common conditional causing pathogens in water (Pseudomonas aeruginosa, Legionella pneumophila) in DUWLs immediately after disinfection, as well as the total bacteria number immediately after disinfection,12 hours after disinfection, a week after disinfection in DUWLs. (2) Hydrogen peroxide silver ion was divided into three concentrations including 2.5%,5%,10%. We compared the detection rates of common conditional causing pathogens (Pseudomonas aeruginosa, Legionella pneumophila) in each group in DUWLs immediately after disinfection, as well as the total bacteria number immediately after disinfection,12 hours after disinfection, a week after disinfection in DUWLs.Result (1) There was no statistical difference in the use years, daily treatment of Dental units among each group. (2) Before disinfection, Legionella pneumophila was not found in each group. The detection rates of Pseudomonas aeruginosa in sodium hypochlorite group, hydrogen peroxide group, hydrogen peroxide silver ion group were 20%,40% and 20% respectively. Pseudomonas aeruginosa was not detected in the other two groups. After disinfection, Pseudomonas aeruginosa and Legionella pneumophila were not detected in all groups. There was no statistical difference in bacteria number among groups in DUWLs, including high-speed handpiece, triple syringes, mouthwash before disinfection (P>0.05). The disinfectant groups could significantly reduce the total bacteria number (P<0.01), and met the requirements of American CDC, ADA and drinking water criterion. There was no significant difference in the total number of bacteria 12 hours after disinfection compared with disinfection immediately (P>0.05), and could meet the American CDC, ADA and drinking water criterion. The difference between control group and disinfection group was statistically significant (P<0.01).There was a significant difference in the total number of bacteria one week after disinfection compared with 12 hours after disinfection and disinfection immediately in the disinfectant groups (P<0.01). The groups of O3, sodium hypochlorite and hydrogen peroxide did not conform to the CDC, ADA and drinking water quality standard. However, hydrogen peroxide silver ion group could meet the CDC, ADA water quality standards.(3) Before disinfection, Legionella pneumophila was not detected in different hydrogen peroxide silver ion concentration groups. The detection rates of Pseudomonas aeruginosa in 2.5%、5% and 10% groups were 40%、20% and 60% respectively. After disinfection, Pseudomonas aeruginosa and Legionella pneumophila were not detected in all groups. There was no statistical difference in bacteria number among groups in DUWLs, including high-speed handpiece, triple syringes, mouthwash before disinfection (P>0.05).The different concentration hydrogen peroxide silver ion group could significantly reduce the total bacteria number (P<0.01), and met the requirements of American CDC, ADA and drinking water criterion. There was no significant difference in the total number of bacteria 12 hours after disinfection compared with disinfection immediately (P>0.05), and could meet the requirements of American CDC, ADA and drinking water criterion. There was a significant difference in the total number of bacteria one week after disinfection compared with 12 hours after disinfection and disinfection immediately in each group (P<0.01). The 10% group could conform to the CDC, ADA and drinking water criterion, 5% group could meet the CDC, ADA water quality standards,2.5% group was able to meet the CDC standard.Conclusion1. Disinfected with different disinfectants and different concentrations of hydrogen peroxide silver ion, Pseudomonas aeruginosa and Legionella pneumophila were not detected.2. Disinfected with different disinfectants and different concentrations of hydrogen peroxide silver ion, the bacteria number of immediately after disinfection,12 hours after disinfection was decreased in DUWLs including high-speed handpiece, triple syringes, mouthwash, and could meet the drinking water standard. Only rinsed by distilled water could not meet the drinking water standard. However, O3 group, sodium hypochlorite, hydrogen peroxide group failed to meet three kinds of water quality standards a week after disinfection.2.5% hydrogen peroxide silver ion group could meet American CDC water quality standards.5% group was able to conform to American CDC, ADA water quality standard. The concentration of 10% could meet American CDC, ADA and drinking water standard.