In the human body, there are over 60,000 miles of blood vessels and arteries. That is a lot of plumbing to keep us alive! The entire field of vascular medicine is comprised of physicians who specialize in different parts of that system to help it all work properly. When you start to have buildup and blockages in your blood vessels it causes severe health issues. If blockages and buildup are discovered, physicians are eager to take immediate action to clean out our internal human plumbing to get us back to optimal health.
In a dental office, there isn’t quite that length of plumbing but there are more hoses and tubes than you find in most building types. This system shuttles water from the city throughout the whole office, and to each operatory chair to help keep people’s teeth clean. Just like our internal plumbing system, it needs to be cleaned and cared for. If there are lapses in cleaning, you can get blockages and biofilms that can make people seriously sick as evidenced by a number of documented outbreaks of infections from water line contamination.
- 2015 – 24 children got NTM (Nontuberculous Mycobacteria) infections
- 2016 – 71 patients developed infections after pulpotomy procedures
- 2022 – A cluster of suspected NTM infections following dental procedures
Let’s look at the microscopic world of waterlines and how they can make people sick.
Let’s start with an environmental analysis. If you look at a dental water line you will notice a few items. First, they are narrow hoses usually around a 1/16th of an inch or 2mm in diameter that are made of some kind of plastic or rubber composite. As we know with food packaging and storage, plastic is porous enough to retain different particles and bacteria. That is why certain plastics aren’t considered food grade, because they are too porous. So, the hoses that are in dental offices can be prone to retain bacteria and microbial activity because of the material used.
Second, the small diameter of the hose also causes a low flow rate through the hose. Water flowing through a dental water line flows at a rate of 60-100mL/min as opposed to 6-12 gallons per minute in a residential home water line. With such little flow, we can’t expect that to clean out the lines.
Third, water lines tend to sit stagnant for long periods of time. It is estimated that water lines sit idle for 22 hours a day, even on a busy patient day. If you only use the hose for a few seconds at a time you are getting a milliliter or two at a time. The water at the beginning of the line could be in that line for a day or two before the hose is used enough to move it all the way through the line.
Finally, when using the hose, you are starting and stopping the water, but you aren’t flushing the hose. Starting and stopping can loosen some of the bacteria and move it down the line, and then when the water stops it attaches to the hose and now you have two places where the bacteria are growing.
Between small diameters, plastic hoses, low flow rates, and continuous disruption of the bacteria the lines are incredible environments to grow and breed bacteria and microorganisms.
But what is growing in the lines? Inside the lines, it isn’t just bacteria. What is forming are called biofilms. One researcher named them “microbial cities”. With biofilms, there is a protective layer that forms over the bacteria protecting them from disruption. Once a bacterium adheres to the surface, it starts multiplying and creating a small protective environment to allow more growth. Once they grow enough some of the bacteria detach and look for a new place to create a biofilm (i.e. when you start and stop the water flow in the hose) Here is a great picture depicting the various stages of biofilm formation and development:
Figure 1. Adapted from Vasudevan, 2014, J Microbiol Exp 1(3): 00014. DOI: 10.15406/jmen.2014.01.00014.
Like other living beings once a home/city is built it gets harder and harder to remove the living organism.
With all of this said it is important to monitor your water lines and make sure they stay clean. This is a two-step process, however. The first step is to test and see if your lines are dirty. It has been shown in studies (link to study) that brand-new water lines can have colony-forming units (CFUs) counts up to 200,000 in as little as 5 days. As a point of reference potable water standards are 500 CFUs or less (link to CDC Guidelines page). But we can’t test that frequently, therefore it is suggested that you test all your water lines at least every 3 months to see if you have any CFUs or biofilms. As part of our Medi Clean and Shield services, we test all operatory water lines every quarter to assist in this process.
If you don’t have any CFUs, congratulations on your commitment to long-term infection control. But you can take a couple of precautions to continue that standard of care. You can flush the lines at least 20-30 seconds between each patient to make sure there is no backflow of the previous patient’s bacteria left in the line. You can also flush for 2-3 seconds before inserting the syringe into a patient’s mouth. This helps flush any bacteria off the tip of the syringe. Finally, you can flush your lines at the end of each day to make sure you don’t have any stagnant water lingering overnight where biofilms can form.
If you do have dirty lines, there are multiple options to solve that problem. Each of these solutions is predicated on the level of contamination. If we find any contamination, we will help give advice or provide you with avenues to address your issues. The solution could be as simple as shocking your lines, or you might have to treat your lines if the build-up is bad enough. In extreme cases, you might have to replace your lines and start over.
If you want more details on water lines, see the links below for CDC guidelines and studies that have been conducted:
MCS helps dental and healthcare facilities become safe places for patients and staff to work and seek medical and dental attention. We help our clients by not only providing long-term disinfecting and infection control protection solutions for their facilities, but also by testing and verifying the cleanliness of those facilities. Every office we have been in has had some level of contamination, and our clients have seen a 100% decrease in microbial activity and an average decrease of 75% in their ATP levels. If you would like help in getting your office cleaner and safer, and have objective verifiable data to prove it, call us today at 469-778-7550 or contact us here.
