Metal air/water syringe tips are anodized on the outside, but the inside is raw metal, that begins corroding from the first use. As they continue to corrode over time, fissures develop, which are perfect pockets to collect biofilm, blood, tissue and material debris.
These elements are virtually impossible to remove from the micro lumen, and continue to collect over time and usage. The collection of such debris prevents steam condensation on the inner walls of the lumen, thus impeding sterilization in the autoclave.
Would you want this in your mouth?
Reflux (also known as aspiration or “suck-back”) is the normal action that occurs when the water button on your air water syringe is released and contaminated aerosol from the oral cavity is retracted into the syringe tip due to negative water pressure.
Placing metal air/water syringe tips inside an ultrasonic solution, introduces more biofilm inside the lumen through the vibration action. The more the solution is used during the day, the more biofilm develops in the solution.
When metal air/water syringe tips are placed inside the autoclave, the debris collected inside the lumen from suck-back, spray-back and the Ultrasonic solution, is literally baked into the fissures, or cavities. This clogs the tip and the debris can be blown into another patient’s mouth.
IN AND THEY
Water within the air/water syringe lumen has been shown to have contamination rates of more than 90%.
Hepatitis C Transmission
In 2013 an investigation into an Oklahoma dental practice confirmed a case of patient-to-patient hepatitis C transmission. 89 of this offices' patients tested positive for hepatitis C, but only one case was directly tied to this dental practice. Four cases of HIV were also found in his patients; the CDC is conducting genetic testing to determine whether those cases are tied to dental office control procedures in dental settings.
"This is the first documented report of patient-to-patient transmission of hepatitis C virus associated with a dental setting in the United States, state epidemiologist Dr. Kristy Bradley said. "While dental procedures are generally safe, this reinforces the importance of adhering to strict infection control procedures in dental settings"
The Dental Advisor test results
The persistent presence of organic and inorganic deposits in the lumens (of air/water syringe tips) could delay or even prevent penetration of sterilizing vapors. A number of reports have demonstrated the presence of accumulated deposits in metal AWS tips that have been reprocessed many times between patient uses. In some instances, the items were cultured and found to be sterile after autoclaving, while other studies demonstrated inconsistent sterilization outcomes.
The Dental Advisor conducted its own tests in their Biomaterials Research Center and found microbial contamination in approximately 10% of the metal AWS tips tested, and concluded:
A general infection control principle states that sterilization of reusable devices requires pre-cleaning. In the particular instance of AWS tips, the small lumen openings preclude visual examination of accumulated contaminants on the rough internal surfaces. Failure to detect the presence of accumulated debris and the inability to clean the lumens therefore provides strong support for the routine use of disposable AWS tips.”
Sterilisation Found Not Effective In Non-Disposable Syringe Tips
ST LEONARDS, Australia/ DUNEDIN, New Zealand: Owing to their internal construction, air or water syringes commonly used in dentistry are generally prone to bacterial contamination. Using disposable rather than non-disposable syringe tips however could potentially decrease the risk of cross-infection between dental procedures, even when the latter kind have been thoroughly sterilised several consecutive times, researchers from New Zealand have reported in the latest issue of the Australian Dental Journal.
Of 68 used non-disposable syringe tips tested for microbiological growth, almost 40 per cent were found to be harbouring different kinds of bacteria after having been sterilised with a Class B autoclave. According to the researchers, the level of contamination did not decrease significantly regardless of the number of additional sterilisation cycles the tips were run through. Flushing the instruments simultaneously with air and water before the cleaning and sterilisation processes also resulted in no difference to the level of contamination, they said.
While control tips of the disposable kind also showed contamination, the level was significantly lower.
The researchers suggested that one of the main reasons for the build-up of bacteria or contaminants in non-disposable tips could be corrosion facilitated by continuous exposure of the instruments to humidity during treatment, which increases the roughness of the surface, allowing potentially harmful micro-organisms to accumulate over time. While such micro-organisms might be harmless, the researchers recommend the use of disposable air water syringe tips over non-disposable tips to reduce the risk of cross-infection.
If you can’t clean it, you can’t sterilize it!
The Dental Advisor Report only confirms results from other testing labs, dating to 1994, in which a university study proved that it is virtually impossible to clean the interior surfaces of a metal tip, required for sterilization. Or, as another expert concluded in agreement with American Dental Association infection control protocols:
"If you can’t clean it, you can’t sterilize it.” He then added: “The disposable plastic tip is the surest way to avoid cross-contamination from patient to patient.”
A 2009 article in a leading European dental publication echoed these findings and cited the British Dental Associations 2003 recommendation to use disposables whenever possible. From a 1997 OSAP report: “The bacteria that enter the tubing are able to adhere to the lining of the tubing and then multiply. Bacteria are continuously released from the surface of the biofilm into the flowing water in the line. Patients and clinical staff are then exposed to these planktonic micro-organisms."
From a 1997 OSAP report: “The bacteria that enter the tubing are able to adhere to the lining of the tubing and then multiply. Bacteria are continuously released from the surface of the biofilm into the flowing water in the line. Patients and clinical staff are then exposed to these planktonic micro-organisms."
According to a 1999 study by Dr. Raghunath Puttaiah of Baylor University, a leading expert in infection control in dentistry, ultrasonic cleaning does not remove all bioburden from within the lumen of metal three-way syringe tips. And, although these tips meet sterilization standards, accumulation of internal bioburden over time can compromise sterilization procedures.
In addition to numerous other reports that agree with these findings, Dr. Martin Fulford, BDS, DgDP, FibMS summarized the situation as follows: "The in ability to pre-clean the inside of traditional metal syringe tips, coupled with the unpredictable nature of steam penetration through fine lumen, means that effective sterilization of such tips cannot be guaranteed. Therefore, the use of a disposable air/water syringe tips to cut cross-infection risk is to be strongly encouraged."