title: Breaking the Chain of Infection: Dental Unit Water Quality Control.
abstract: BACKGROUND
  The air-water syringes, ultrasonic scalers, high speed air turbine handpieces are connected to dental units by a network of small-bore plastic tubes through which water and air travel to activate or cool the instruments and it had been shown that this system is extensively contaminated with microbial biofilms and pose a potential risk of infection for patients as well as dental professionals.
  
  
  OBJECTIVE
  To evaluate and compare the efficacy of various disinfectants in reducing the microbial colony count in water derived from Dental Unit Waterlines.
  
  
  METHODS
  Five random dental units were selected and samples were collected before and after intervention with 5 disinfectants (0.02% H2O2 continuously, 0.02% H2O2 continuously with shock treatment with 0.25% H2O2 weekly, 0.12% Chlorohexidine and 12% Ethanol overnight, 1:50 Original Listerine overnight, 2% Sodium Perborate and 2% EDTA 5 minutes in morning) using different disinfection methods for 4 weeks. Samples were cultured on Reasoner's 2A (R2A) agar for microbial counting.
  
  
  RESULTS
  Results were recorded as Colony forming units/ml (cfu/ml) and were evaluated statistically. Results showed that all the dental unit waterlines were heavily contaminated with microbes before any intervention. After 1 day of disinfection regime the counts reduced significantly and showed progressive reduction in consecutive weeks. Goals set by ADA & CDC were ultimately achieved at the end of 4 weeks.
  
  
  CONCLUSIONS
  All the disinfectants were equally effective in reducing the microbial colony count of DUWLs, irrespective of their concentration and method of disinfection.
authors.affiliation: Senior Lecturer, Department of Prosthodontics, ITS College of Dental Sciences & Research , Muradnagar, Ghaziabad, UP, India .
authors.forename: Amrita
authors.initials: A
authors.lastname: Pawar
authors.affiliation: Professor and Head, Department of Prosthodontics, MM College of Dental Sciences & Research , Mullana, Ambala, Haryana, India .
authors.forename: Sandeep
authors.initials: S
authors.lastname: Garg
authors.affiliation: Associate Professor, Department of Microbiology, MM College of Medical Sciences & Research , Mullana, Ambala, Haryana, India .
authors.forename: Sonia
authors.initials: S
authors.lastname: Mehta
authors.affiliation: Professor, Department of Prosthodontics, MM College of Dental Sciences & Research , Mullana, Ambala, Haryana, India .
authors.forename: Rajat
authors.initials: R
authors.lastname: Dang
keywords: Dental unit waterlines; Disinfection; Hydrogen peroxide; Infection control