How does time-dependent dental unit waterline flushing affect planktonic bacteria levels?

The purpose of this study was to evaluate how time-dependent waterline flushing affects the presence of biofilm in otherwise-untreated dental unit waterlines (DUWLs). Water samples were obtained from twelve highspeed handpiece DUWLs located in the undergraduate treatment clinic at the University of Missouri-Kansas City, School of Dentistry. Baseline water samples (50 cc) were collected prior to the start of continuous flushing.