GAP Australasian Dentist Mar Apr 2020

40 Austràlàsiàn Dentist àealtà & wellàeàng Q Professor Walsh, what is biofilm? à Biofilm is a very well structured layer of different microorganisms such as bacteria and fungi that forms in wet places. Mould or slime in your shower is biofilms, as is dental plaque. We all know how difficult it is to remove these. àhe tubing inside dental units is a great environment for the growth of complex biofilms. Q How does biofilm affect human health? à àhere are several conditions linked to dental unit waterline biofilms. àegionella pneumophila can cause àegionaire’s disease, as well as a milder condition called Pontiac fever, that many people mistake for a viral influenza. àhe most at-risk patients for these infections have a compromised immune system. àhey could be elderly, diabetics or smokers. àhey are more prone to infections from aerosols that are generated by ultrasonic scalers and high speed handpieces. àhese aerosols transmit the microorganisms from the dental unit waterlines into the air. Both patients and staff breathe this aerosol, and potentially can get infected. Q What are the findings from research into water quality in dental unit waterlines? à àn the last 25 years we have done a range of studies around the topic of dental unit waterline exit water quality. What we have found is very consistent with reports from àK, A and àurope. All these studies confirm that if there is no flushing and no chemical additives used, the level of bacteria will be very high, and certainly above the 200 CFà/mà threshold limit recommended by the ADA. àhis is the same threshold used for dialysis water. We also have found variations between the exit water-quality in different brands of dental chairs. On the other hand, we have seen that when continuous chemical treatment of water is taking place, combinedwithperiodic shock treatments and water testing, the levels of bacteria are very low. ànfortunately, only about 1 in 5 of the dental practices would comply with the current threshold level and most surgeries do not even realise that they have a problem. Q Is the water coming out of the dental unit the same quality as the water being fed in? à ào, this is not the case at all. ànside the dental chair are several meters of very narrow dental tubing, where the water flows very slowly and has a tendency to stagnate. àf there is no active chemical treatment of the water treatment, the quality of the exit water is never as good as the input. àhis has led to the statement, “àt’s no wonder, when your patients rinse or drink from the dental cup, that you then tell them to spit that water out into the spittoon.” Q Why is it important to test the exit water from waterlines on regular basis? à With different types of tubing and internal designs of dental chairs, as well as water of different quality being fed in the chair, plus different locations and climates, this all gives a very complex system, so each chair needs to be individually measured. àf you actually never test your exit water and simply rely on speculation, you will never know how your water is performing according to the guidelines. Q Why is it important to do shock treatments? à A shock treatment is different from continuous water disinfection. àt is designed to detach and break down the biofilm, rather than just suppress the growth of bacteria. Once microorganisms have formed into biofilm, they are much more difficult to kill with externally applied chemical agents. A shock treatment is a specific intervention to detach and break down the biofilm. àhose fragments can then be rinsed through, leaving the surface of the tubing clean. Q Can domestic bleach solution be considered a suitable shock treatment? à à have concerns regarding using household bleach as a shock treatment. àhere are many problems with the stability of bleach (sodium hypochlorite), for example, it degrades with time, elevated temperature and on exposure to light. ànless you test the level of free available chlorine in domestic bleach, you do not know if it is active at all. àt could have been sitting in the warehouse for a long time, and lack potency. When we use a designated product designed specifically to break down waterline biofilm, it has stabilisers added, so it is chemically active, and its efficacy is predictable. Domestic bleach can also interact with the control blocks in some brands of dental chair, and cause severe corrosion. You would never just try and see, without knowing from the manufacturer that it was safe to use. Q Once the waterlines are clean, how do maintain a clean system? à Once the system and clean and tested, we need to use an antimicrobial chemical to stop bacteria from replicating. àhere are different products that can do this function. àhey differ in terms of how quickly they work against bacteria, and how stable they are over a longer period Bacterial hazard in dental practice. How clean is the water inàyour dental unit? We talk to Professor Walsh about the current problems with water quality in DUWL and new recommendations from ADA guidelines. Professor Laurence Walsh Article by Alpro /Biodegree Pty Ltd, the specialists in clean water solutions and Biofilm Removing Systems.