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How do I best disinfect my operatory?

Dental instruments and tools in a dentist office

This question was submitted by a general dentist: What is the most responsible and efficient way for dental offices to clean an operatory between patients and what disinfectants should we be using and where?

Drs. Nita Mazurat, from the University of Manitoba, and Suham Alexander provided a quick initial response. 

This is probably the most frequently asked question by clinicians dealing with infection prevention and control. As a matter of fact, the real question is “which disinfectant should I use in my office?” The answer would be much easier, if there wasn’t such a wide variety of products offered on the market. However, the reality is that there are as many alternatives as there are disinfectant producing companies and, to further confuse matters, the product formulations are diverse. Clinicians want fast, cheap, and effective solutions and, as the adage goes, you do very well, if you get to choose 2 out of those 3 qualities! 

One overlying principle is the use of products which claims have been validated. Since there is no practical way for the dental team to determine the effectiveness of the disinfectant used for patient contact surfaces, clinicians have to rely on a number of aspects to trust that the product will prevent cross-contamination to patients and oral healthcare providers. In Canada, the Drug Identification Number (DIN) attached to the product guarantees that the product meets Health Canada’s Food and Drugs Act standards.  

The Centers for Disease Control and Prevention (CDC) recommends that an “intermediate-level disinfectant should be used when the surface is visibly contaminated with blood or OPIM (other potentially infectious material).” Since dental care usually involves transparent saliva spatter that is difficult to spot on surfaces, an intermediate-level disinfectant, also known as a tuberculocidal-level disinfectant, should be routinely used on clinical contact surfaces, including countertops and dental unit surfaces. This eliminates the uncertainty around whether or not the surface has been effectively cleaned, if and when it is contaminated with body fluids. That leaves one downside: the use of a more costly intermediate-level disinfectant when in fact a low-level disinfectant could have been used instead. Nonetheless, considering the amount of time required to decide which disinfectant to use certainly offsets the cost of the appropriate product, resulting in confidence that no error in judgement was made. 

Another principle to consider is that to be effective, products, including disinfectants, must be used according to the manufacturer’s instructions. This includes, but is not limited to, the product shelf life, dilution, temperature (avoid freezing for example), application method, and product contact time with the surface to be effective, the latter being a critical aspect of disinfectants. Therefore, the surface must be free of any organic and any inorganic substances that would prevent the disinfectant from coming in contact with microorganisms on the surface that is being disinfected. By using barriers, the amount of time spent removing organic and inorganic materials is decreased. Furthermore, CDC states “after removing the barrier, examine the surface to make sure it did not become soiled inadvertently. The surface needs to be cleaned and disinfected only if contamination is evident. Otherwise, after removing gloves and performing hand hygiene, DHCP (the dental health care professional) should place clean barriers on these surfaces before the next patient.” Most offices perform this procedure and routinely disinfect the surface prior to placing a clean barrier, always assuming that the barrier was breached. However, the difficulty in following the CDC’s comment lies in the nature of saliva being transparent and undetectable making the term “contamination is evident” less than an ideal measuring stick.

It is important to reiterate and over emphasize the importance of following the manufacturer’s instructions on the use of products (IFU or Instructions for Use). Most dental chairs manufacturers do not recommend the use of chemical disinfectants on the leather or naugahyde material of the patient chairs, the operator’s, and the assistant’s stools, preferring the use of an (antimicrobial) detergent and water.

When purchasing countertops, consult the dental office designer who is typically familiar with the use of countertop materials as well as the need to routinely use disinfectants. If available, follow the instructions from the countertop manufacturer. There is probably no disinfectant on the market that will effectively preserve the countertop color and sheen while subjected to the known rigors of disinfection in a busy dental office.

The other area of disinfection is the laboratory. Generally, once laboratory items (impressions, crowns, wax rims etc.) are thoroughly rinsed, they should be immersed in a 1/10 dilution of sodium hypochlorite (5% or 5.25%) solution freshly made daily, or thoroughly sprayed with same solution and left in contact for 10 minutes. This is a cost effective way to disinfect almost all laboratory items. Manufacturer’s instruction must be followed since not all alginates can be immersed. After 10 minutes, lab items must be rinsed. Crowns can also be sterilized in a regular steam sterilizer process, but time is generally an inhibitor factor.

Do you have any other question related to this topic? Email us at oasisdiscussions@cda-adc.ca

15 comments

  1. A few practical thoughts on surface disinfection products: While the effectiveness of disinfectants are often measured by “TB kill time”, our main concern in dentistry is blood-borne diseases, hepatitis in particular. A surface must be clean of blood and saliva before it can be disinfected.
    Blood and saliva are best cleaned away by a water-based product with a surfactant. I have used Pathex, which I think is a phenol-based product. I preferred it over another brand I tried because Pathex contained sufficient surfactant to help clean the surface. One of the phenol based products I tried just “beaded up” on plastic trays indicating it didn’t have enough surfactant.
    I eventually settled on a third phenol-based product because it was a little cheaper. Soon afterwards, my new assistant insisted that phenol based products were too toxic and she convinced me to go with Cavicide which has been our mainstay product ever since.
    One disadvantage with Cavicide is it discolors certain plastics, such as the clip-line for the “Root-ZX”. Another is that it only comes pre-mixed, so we end up with 20 liter plastic jugs that take up a lot of room in the recycling. At least phenol-based products come in a concentrate so you just buy a 2 liter jug.
    I don’t know what type of disinfectant Cavicide is. It’s not a phenol.
    We used Germ-X for a while and found it to be satisfactory. I believe it is based on 70% ethanol with enough water to dissolve blood and saliva.
    We still fill the little alcohol pumps in the operatories with 70% isopropyl alcohol. I think it is an acceptable way to occasionally wipe a small item with a 2 by 2 gauze. Long-term use of alcohol based products will probably take the sheen off the counter-tops.
    I believe that 99% isopropyl alcohol has no significant value. It will not dissolve dried blood.
    Diluted bleach is effective and cheap but I don’t recommend using it regularly because it quickly corrodes metals. I ruined a handpiece by repeatedly wiping it with bleach.
    Once the operatory surfaces are cleaned, a second application of disinfectant should be applied and left on according to the manufacturers’ recommendations. This is where “kill time” and toxicity come in. Mild disinfectants need longer contact time. Stronger disinfectants can irritate the eyes, nose and lungs.
    Individual dental assistants have their own ergonomics of cleaning and disinfecting an operatory. Experienced assistants don’t need much supervision. What they need most is an adequate amount of time to get their many jobs done between patients.
    The public has the right to judge us by how clean our office is. It correlates positively with our infection control protocols.

    • What an excellent and practicalcomment Dr Flagg. I am, of course, unable to provide feedback on products but it is useful for other offices to hear about your experiences with particular brands. Just a quick note about the use of ‘intermediate’ or tuberculocidal disinfectants and I should have made myself more clear from the onset. The reason for using this level of disinfectant is to prevent the transmission of bloodborne diseases. If a disinfectant is effective against tuberculosis which is difficult to kill, then it will also be useful as a cidal against HIV, HBV, and HCV.
      Another point that you scored highly with is that we should be removing materials immediately at point of use. Organics are most easily removed with gauze that has been wetted with water – but caution is required for cleaning off sharps to prevent injury to the oral health care provider who is cleaning the instrument. Follow manufacturer instructions for point of use cleaning of inorganic materials such as luting agents.
      Dr Mazurat

    • While reading your response I felt I must point out that Hepatitis is NOT killed with bleach. It is Not effective in killing this blood borne disease.

      • There are forms of commercial sodium hypochlorite disinfectants on the market that are not effective against HBV, however, the CDC publication “Guideline for Disinfection and Sterilization in Healthcare Facilities – 2008 (http://www.cdc.gov/hicpac/Disinfection_Sterilization/6_0disinfection.html) discusses how various concentrations at various times of sodium hypochlorite are effective for M. tuberculosis inactivation. No disinfectant causes reliable inactivation of HCV kill in needles, however, this is due to the size of the lumen and ability of the disinfectant to infiltrate in the presence of body fluid. In order for disinfection procedures to be effective, organic and inorganic materials must be removed either through vigorous cleaning of the surface or by thorough rinsing under running water prior to final application of the disinfectant which must then stay in contact with the clean surface for the manufacturer recommended time for disinfection.
        Dr Mazurat

  2. Thank you for your recommendations regarding operatory disinfection.

    What are your thoughts on biological monitoring of instrument sterilization efficacy? With what frequency do you feel that this should be performed?

    • Hi Tim,
      Without new guidelines from CDC, your Provincial association, or the CDA, the best answer in Canada is from the Canadian Standards Association Technical Committee on Sterilization and from the Canadian Association for Medical Device Reprocessing. I will answer your question because it is THE most asked question about monitoring in Canada, however I want to be absolutely correct in providing your answer so I want to confer with my colleagues with both of these groups.
      However, while I am doing this, here are some of the questions that you will need to answer for your own office:.
      – Are the people who perform the sterilization following the manufacturer’s instructions (with no exceptions for accuracy) for use of the sterilizer?
      – How many loads are processed daily – are the instruments being loaded so that there is adequate space for the steam to access every instrument all around the package or are the packages too close together to allow this (ie are we following manufacturer’s instructions)? For this analogy, I ask people if they have ever roasted two turkeys of the same weight each in the same roasting pan and did not butt them up against each other. These turkeys would only need sufficient roasting time for their weight. However, if these same two turkeys were butted up tightly against each other in the roasting pan, they would not be cooked where they butt against each other because the heat could not reach that area. The same is true of steam sterilization. If the sterilant (generally steam) cannot penetrate the package to reach the instrument, these instruments will not be sterile. That is why the internal chemical indicator needs to be placed in the most inaccessible area of the instrument package – and why it is best to use the internal indicator that is sensitive to all the parameters (also known as a Class V integrator although there will eventually be a name change to internal indicators).
      – Does your Provincial dental association request that you keep a log to demonstrate use of a biological indicator?
      – Do your patients request that you keep a log of use of biological indicator?
      – What seems logical in your office? (It would seem expecially logical to monitor loads of critical instruments ie those that touch bone or surgical instruments).

      Dr O’Keefe and I are planning on developing and presenting a series on Sterilization. Because there are no ‘musts’ for most dental offices in Canada (Alberta being a notable exception), it is up to the individual office to determine its own standards – however, we need guidance with making the decisions on the standard and, as promised, I will return to your question with these according to CSA and CAMDR as there are really no changes from CDC at this time.

      Dr Mazurat

    • Hi Tim,
      Again, in the absence of published guidelines from your Provincial dental association, I still feel that I need to provide you with direction. Your staff is probably very careful about monitoring your sterilizer’s activities, however, ‘listening’ and ‘observing’ that the parameters are reached, should be recorded and that is often not practical. For me there is no question that validation using an objective method that your sterilizer is working effectively is needed. This should be done everyday because we can never predict when a mechanical device is not working properly AND instruments should not be released until the spore test has been cultured. That is why the one hour test is frequently used in offices where there are only sufficient instruments for one day’s operations. A log must be maintained stating the date that the spore test was performed, the results, the name and initial of the person who performed the test and incubation. In Canada, we do not state how long these logs should be saved. In parts of Europe and in Australia, the standard is to keep them for up to 30 years. Why? Because Hepatitis C can take up to 3 decades to surface so this is demonstration that due diligence was maintained.
      I recognize there is cost associated with these recommendations. However, patient safety trumps all other parameters. Furthermore, the loss of a dentist’s reputation if there was a recall of their patients as there have been in the United States in the last few years, is something that should be considered when making decisions about use of spore testing.

  3. Our practice, prior to my partner and I purchasing it from the retiring doctor, have tried many products with so so acceptance. I used tb Minuteman all through school and this product seems to gain the most satisfaction all round with staff. Smell. Speed. Kill list. Cost. We tried a hydrogen peroxide-based product, but it is very hard on chrome surfaces and will actually eat through your gloves in time.

    • Thanks for this comment Rick. If the infection prevention and control experts in your Faculty were comfortable with all the parameters, and the biggest critics or experts (YOUR staff) are happy, thank you for writing in. Again, I am not comfortable with recommending individual products. It is so important that we use the right level disinfectant for clinical contact surfaces which is known as intermediate or tuberculocidal for attaining adequate kill against the bloodborne diseases. Additionally, as with everything in the dental office, it must be used according to manufacturer’s instructions (exactly not just ‘good enough’!). Always check to see that products such as this have drug identification numbers as well.
      Again, thank you for taking the time to write a post!

  4. Biological monitoring is the gold standard, but I’ve never done it because I thought the cost was a bit high for a small office. I think the weak link in infection control is probably human behavior, not equipment malfunction.

    • Thank you for this comment as well Dr Flagg.
      The weak link is most often human behaviour, however, it is comforting to know that your equipment works properly as well. There is no way to know with certainty, even using a BI in every load that the individual instrument is sterile.
      Here are some thoughts you and your staff may wish to consider regarding your question:
      – Soon, Provincial associations and patients will probably start asking us for our office logs of BIs so you may wish to be ahead of the curve on this.
      – Are there enough instruments in the office that you will release instruments only after the BI is read (in 24 hours) or will you consider a faster BI? (two hour for example)?
      – There is not only the cost of the BI, but also the cost of internal indicators in loads that do not have a BI.

      I have indicated to another posting that I will speak to the other members of the Technical Committee for Sterilization from the Canadian Standards Association for their direction according to the Z314 document on Steam Sterilization. We need to be practical, have to be careful about costs in order to survive, and we need to be safe.

      I will return to this discussion in about a week as I am presently away from my office.

      Dr Mazurat

  5. Thank you Dr Mazurat! This has been a good “thread”.

    • Hi Larry,
      I just made a comment to another kind person who took the time to write to us about biological indicators and I am going to provide you with the same information.
      I know the correct procedure and that is to routinely use a biological indicator. Canadian Standards Association recommends daily use AND instruments should not be released until the spore test has been performed AND a log must be kept to demonstrate correct functioning of the sterilizer. It is our responsibility since we have been given the privilege of treating our patients, to keep them safe. When we know what is right and how to do it, we need to do what is right. Patient safety trumps all else! That being said, consider mere financial cost when balanced with your reputation should there have been a failure, even though you have excellent staff who try their best everyday.

      Thank you again for writing to us.
      Dr Mazurat

  6. Dr. Elizabeth Johnstone

    Surfaces are one thing, inside suction tubing is another…..which the profession seems to be ignoring. The gross contamination inside suction tubing in dental operatories needs to be addressed. Why are they not routinely changed & sterilized between patients? The thought of closing lips around the end of a saliva ejector creating a backflow of contamination turns my stomach. Yet this happens continually in dental offices. I use hospital grade suction tubing & it is changed after every patient. My suction system is different than the typical dental operatory system, but surely something simple can be done to allow this tubing to be used on the standard dental units. Perhaps a $.25 disposable plastic adaptor? I refuse to put my lips around any suction tip. Think about it. Most of this tubing has been there for years!

    • Hi Dr Johnstone,
      The guidelines that still form the backbone of dental infection prevention and control recommendations is the 2003 CDC guidelines. There it was acknowledged that backflow can occur with low-volume suctions when a seal around the saliva ejector is created as you’ve described. Also, if a length of the suction tubing holding the tip is positioned above the patient’s mouth or during simultaneous use of other evacuation equipment. The implication in the guidelines was “beware not to allow these practices during care”. The link is
      http://www.cdc.gov/oralhealth/infectioncontrol/guidelines/index.htm

      To answer your comment about sterilizing suction tubing is: congratulations! Compliance is such an issue in healthcare settings, especially when there are additional costs associated with day to day functioning of the office. Why don’t you make an office manual that sits in the waiting room to let your patients know that you put their safety first by being above and beyond the standards required?
      Thank you for your post.
      Dr Mazurat

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