ABSTRACT:
The main aim of this study is study the effects of alcohol and hydrogen peroxide in determination the extent of microbial contamination in dental unit water lines .The study included one hundred twenty water samples were collected from dental unit water lines at the clinics of the college of Dentistry/University of Babylon located in the center of the province of Babylon during the period from October 2016 to April 2017. The water samples were subjected to different methods for identification bacteria using traditional bacteriological method. After obtaining baseline water samples, the dental unit waterlines were treated with alcohol 96% and hydrogen peroxide 1% where the two disinfectants were used in treatment and their inhibiting effect was compared.The highest contamination rate of all water samples were found in the bottle in both disinfectants alcohol and hydrogen peroxide.There weresignificant difference in Mean ± SD when treated with disinfectants.hydrogen peroxide was found to be the most effective in reducing the microbial contamination. Improving the water quality from dental unit water lines are of considerable importance. It were stated highest contamination rate of dental unit chair was found in the bottle and hydrogen peroxide disinfectant was more effective than alcohol.