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November 30, 2017
Current CDC guidelines and standard best management practices (BMPs) in infection control (as well as many local regulations) recommend performing a spore test on your sterilizer weekly. A test of your sterilizer using a biological indicator (“BI”) is necessary to confirm that it is effective at rendering loads sterile. But what happens when your sterilizer fails the test? What can and should you do?
First, remove the sterilizer from service. You can’t use a sterilizer unless you know it is properly functioning. Next, repeat the spore test. According to studies, the most common cause of failure of a spore test is improper handling of the test media resulting in post-sterilization contamination. A simple re-test while exercising caution in handling may result in a passed test and you can resume use of your sterilizer.
There are a number of other operator-related issues that could result in a failed spore test, including:
Review proper sterilization procedures and techniques with staff before repeating the test. Then perform a second test, making sure certain operator-related issues have been addressed and/or assurances taken to avoid them. If the second test also results in failure, it’s time to start looking more in-depth at your sterilizer.
Most automatic sterilizers will display error codes if there is a failure during a sterilization cycle. We’ve decoded the errors for some sterilizers (such as the Statim) in Practice Tips #20 and #21. Check these out if you are getting any error messages.
If your sterilizer is not displaying any error messages (or if you have a manual sterilizer), you’ll need to rely more on your powers of observation.
In order for a sterilizer to render a load sterile, it requires the presence of a particular temperature and pressure for a minimum amount of time. These three things are related. The greater the temperature and pressure, the lower the time required. Most autoclaves run at about 135° C (275° F) and 30 psi (pounds per square inch), with a cycle time at that temperature and pressure of 3-7 minutes. This is all that is required to achieve overkill, so sterility can be assured (see steam sterilization principles).
Run a cycle and observe your sterilizer throughout the cycle. Watch for any obvious signs of problems, such as steam leaks. Make certain the sterilizer achieves full sterilization temperature and pressure (using the gauges on the sterilizer). Have a stop watch handy and time how long the sterilizer is at full sterilization temperature and pressure and compare this time to the specifications in your owner’s manual (minimum should be 3 minutes, of course).
If steam leaks are evident, replace the leaking component(s) or correct other mechanical issues that may lead to a leak (e.g. lubricate the door hinges on a Midmark Ultraclave). If it is a door gasket issue, see Practice Tip #93 to see how to replace and install them properly.
Once any mechanical problems have been addressed and you have a successful spore test, you may return your sterilizer to service. Log the successful spore test in accordance with local regulations. Be sure to keep the log for as long as prudent for legal reasons.
A number of the possible causes for a failed spore test can be the result of failed components, that should be replaced as part of your routine sterilizer maintenance. Most sterilizers require replacement of various components annually, although many have more frequent requirements. Contact us for specifications for you sterilizer or check your owner’s manual.
In order to be assured your sterilizer is functioning properly and your staff is operating your sterilizer consistently and correctly, it’s important to perform regular biological testing of your sterilizer. As many failures can be the result of operator error, it’s also a good idea to periodically review the operation of your sterilizer with staff. You can print and post our routine sterilizer maintenance schedule in the sterilization area for your staff to reference as well. It may be convenient to bookmark or print and keep handy our issues of Practice Tips devoted to trouble-shooting sterilizers or decoding error messages.
SPECIAL: American Dental offers Crosstex® sterilizer spore tests, monitoring mail-in services, and integrators for your convenience. Take 10% off through December 31st, 2017.
October 31, 2017
It’s been well over a year now since the CDC published their “Summary of Infection Prevention Practices in Dental Settings” in the Spring of 2016. Despite using the term “summary” in the name of this 44 page document, the CDC has come out with completely new rules for infection control in the dental office (in addition to summarizing previously published guidelines).
This month, we'd like to discuss the dramatic changes to the guidelines for sterilization of dental handpieces. Page 14 of the CDC document specifies (emphasis added):
“Dental handpieces and associated attachments, including low-speed motors and reusable prophylaxis angles, should always be heat sterilized between patients and not high level or surface disinfected.”
What does this mean to you? You cannot re-use a handpiece on a patient unless the entire handpiece and all components have been heat sterilized — even slow-speed handpieces (and components) that are only being used for prophylaxis.
Unfortunately, several popular hygiene handpieces on the market do not conform to this specification and must be removed from service. Handpieces with any drive component that cannot be heat sterilized are now only suited to personal use, use in a veterinary office, or use outside of the country (such as for mission trips).
Drive mechanisms that aren't heat tolerant (cannot be autoclaved) are commonly encountered with many “stand-alone” electric units, but all systems must conform to the new standard. Any component with any type of gear, drive shaft, or similar mechanism must be autoclaved.
Fortunately, most air-driven handpieces on the market are fully autoclavable and have been for decades. Periodic removal of motors and other components should already be a part of your office’s routine handpiece maintenance, now you just need to increase the frequency.
The CDC guidelines were the result of several studies (mostly conducted by various branches of the US military) that showed contaminants had a tendency to work through the drive mechanisms of slow-speed handpieces and contaminate all of the components (even those that do not enter the oral cavity). These studies have shown a high probability of contamination of all handpiece components. The risk of contamination is very real.
In the infection control guidelines, the CDC goes on to state: “Although these devices are considered semi-critical…” and a major handpiece manufacturer has seized upon this statement to claim that their motor does not need to be heat sterilized as it is non-critical. However, all motors are non-critical devices. That is in the nature of a motor. Under normal circumstances, a motor should never contact mucous membranes or non-intact skin. The CDC explicitly spells out that handpieces “including low-speed motors,” must be heat sterilized. It is clear motors must be heat sterilized, regardless of their standing— critical, semi-critical, or non-critical. To attempt to skirt infection control guidelines based on a loose interpretation of a technicality is a dangerous prospect and not something we can recommend, nor support.
We recommend reviewing Practice Tips #71 & Practice Tips #72 for definitions of a motor, a handpiece, and an attachment to further clarify why the CDC’s statement regarding motors is so important.
As most handpieces on the market are already autoclavable, there are a number of economical solutions available to help you remain compliant. American Dental Accessories carries many affordable, reliable, and autoclavable hygiene handpieces. Handpieces like the American Hygienist or the Vector MICROLite are economically priced, ergonomically designed, and fully autoclavable to help your hygiene department stay compliant.
Feel free to call or e-mail us with any questions you have pertaining to the guidelines, as well.
There are a number of other developments in this latest document from the CDC. We recommend downloading and taking some time to familiarize yourself with it, so you can remain compliant in all aspects of infection control. In addition to the new information pertaining to handpieces, the CDC summary includes convenient infection control checklists for use by your office staff and other helpful tools. The previously published 2008 CDC guidelines are 161 pages. The new summary is a much more easily digested 44 pages. Every dentist should read it. Make certain your office staff is familiar with it too.
September 30, 2017
The sterilizer is one of the most important pieces of equipment in the dental office. Without a sterilizer, you can’t have sterile instruments and you can’t perform dentistry. Keeping your sterilizer running is integral to keeping your office running.
In previous issues of Practice Tips we’ve discussed basic function and troubleshooting common to all sterilizers and sterilizer routine maintenance. In each of these issues, we’ve mentioned the sterilizer bellows, a component used in all autoclaves. This month, we’re going to take a more in-depth look at the bellows.
As I’m sure you’re all aware, in order to render instruments sterile, an autoclave needs to subject them to super-heated steam under pressure at a specified temperature for a given time (most autoclaves will deliver optimum performance at 135° C at 214 kpa i.e. 275° F and 30 psi maintained for just a few minutes).
At the beginning of the cycle, water enters the chamber of the autoclave (containing the instruments to be sterilized). The chamber heats up, converting the water to steam, saturating the instruments. The steam is under pressure, so the fine grooves and recessed areas of the surface, and even internal passages of the instruments, will come in contact with the super-heated steam.
In order for the chamber to pressurize, it needs to breathe. As your autoclave heats up and the water begins to boil, the air in the chamber needs to vent, so it can be displaced by steam (allowing nothing but steam to fill the chamber of your autoclave). The bellows opens and closes throughout the cycle (in response to the changing chamber conditions), allowing air from the chamber to exhaust and be displaced by the steam, and to allow the inlet of fresh air as the chamber cools and the steam condenses.
A malfunctioning bellows can prevent full sterilizing pressure and thus temperature. There is a linear progression between the two conditions— leading to an under pressure condition. A failing bellows can also prevent fresh air in as the autoclave attempts to cool, which leads to an over-pressure and over-temperature condition.
Staying aware of the relationship between temperature and pressure can help troubleshoot a failing sterilizer. The following table is a handy reference of this progression between the two:
A few common designs of the bellows are pictured below. Compare the photos to what is in your sterilizer to familiarize yourself with your sterilizer’s components.
The bellows is one of the key components to allow pressurization of the chamber and should be one of the first things to look at should you have a pressure-related issue, (along with the door gasket).
As the bellows opens and closes throughout the cycle, it can be prone to wear and should be replaced annually as part of your routine sterilizer maintenance. This is why the appropriate bellows is included with each of our sterilizer preventive maintenance kits.
With routine maintenance of the bellows, both you and your sterilizer can breathe easy knowing that your instruments are sterile.