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. Additional 50 cc samples were collected after two-, three-, and four-minute flushing intervals from the baseline. The levels of planktonic bacteria in DUWLs were quantified by counting colony forming units (CFUs). In addition, segments of water tubing from each of the highspeed handpiece waterlines were examined by scanning electron microscopy, which confirmed the presence of a residual biofilm in the lumen of each dental unit waterline. A one-factor repeated measures ANOVA showed a statistically significant (p<0.01) reduction in CFUs at all intervals compared to baseline and between each successive time interval. Indeed, after four minutes of continuous flushing, all waterlines still harbored CFU levels that exceed current American Dental Association (ADA) recommendations. It was concluded that water flushing of DUWLs produced a statistically significant reduction in planktonic bacteria at each time interval compared to the baseline and between each successive time interval. However, the level of CFUs after four minutes of continuous water flushing still exceeds the current ADA recommendations for acceptable levels of microorganisms.

Medical education in isolated areas by cycling videocassettes

A fresh perspective on an old and growing problem. How to reach and teach impoverished and isolated people, out of range of standard broadcast methods, the rudiments of health and hygiene? Suggested is a carefully prepared system of cycling videocassettes, to effect the dissemination of current medical information from leading medical centers to medical and paramedical people in the "bush". Conversely, the feedback from the field would benefit the medical centers in terms of customs, semantics, and specific case histories. Hopefully, such intercommunication will lead to a marked improvement in human relations.