Years ago, in an attempt to combat the issue of microbial contamination of dental unit waterlines, dental delivery system manufacturers introduced independent bottle systems. As you probably know, these bottle systems provide delivery units with an independent source of water not connected to the city water supply. These dental bottles typically hold between 750mL to two liters of water.
The basic line of thinking with these systems was essentially this: more control over the quality of the “input” water to the system via independent bottles would enable higher quality “output” water. Using sterile water in a bottle could provide at least nearly sterile output, right?
Unfortunately, no. This idea sounds good in theory, but isn’t sufficient in practice.
Even returning a dental bottle filled with otherwise sterile water to its manifold introduces contamination. Airborne bacteria and microbes present on the surface of the dip-tube inserted into the bottle can recontaminate the system almost immediately. Not to mention the recolonization of water that occurs within the system regardless of how the water is delivered.
In fact, if not rigorously maintained, bottle systems can actually be worse in terms of microbial contamination than directly connected water sources. Having to remove the bottles to refill them throughout the day is like introducing mini “water line breaks” all day long!
Even the ideal-quality input water can quickly become contaminated in dental unit waterlines. For this reason, regular routine maintenance and the periodic use of antimicrobial cleaners are absolutely necessary to control microbial contamination. It's important to understand the various standards in place for microbial content of dental water, and the steps necessary to measure and combat contamination of dental unit waterlines.