Hi Anon.
Having spent the first nearly decade of my career in microbiology - this is always the key question. If there is no guidance out there from the regulatory authorities that obviously doesn't mean that there are no expectations out there because general GMP compliance does recognize that the product should not be harmful to people and infections obviously are harmful.
That said, I am not specifically in the dental device space so I can't competently speak to what the actual requirements are in that particular area of the industry. However, I can provide some things to consider as you manage the process and if necessary begin developing your own specifications for microbial load allowances.
1. First rule is always to never rule out potential for contamination without strong objective evidence. I have seen plenty of situations where environments that were originally considered too hostile to support microbial survival (or even in some cases microbial growth) showing contamination of the product with some unexpected organisms.
2. What type of products are your selling? Are these amalgams or are they dental x-ray equipment or something in between? This will greatly impact what sort of control you need to have in place as well as the plan for any action or alert or failure limits that you might need to employ or the types of organisms considered to be "objectionable" in/on your devices.
3. Consider you situation holistically in that you don't just need to ensure that the product is microbially safe but also consider your environmental microbial profile and even the profile of the individual components being used. How are they managed? How do your suppliers contain microbial contamination (or do they at all)? What processes or barriers are in place to mitigate risk of microbial ingress into your product via the environmental route in your production facility and process? Is there a post-sterilization or mitigation process in place like gassing or autoclaving?
4. Once all of this is understood you have to manage essentially 2 different types of specifications:
a. Microbial limits - this is the test of the overall number of organisms in or on your product. Depending on the type of product I have seen this be anywhere from <0 colony forming units (CFU) [sterile] to upwards of <10,000 CFU. This is entirely dependent on the use of your product as well as any potential steps taken in the process to reduce microbial load.
b. Objectionable organisms - this is a test whereby you ensure that microbes that you or your company's expert have determined are unacceptable in/on the product. For example, in the case of dental items I would expect that your company would like many of the key enteric microbes (e.g., E. coli; Salmonella; Enterobacter; Micrococcus; Clostridium; etc.) to be objectionable. But you might not list something like Burkholderia cepacia or Pseudomonas aeruginosa because these organisms are not as likely to cause infection. Or maybe you do list these organisms because your product is expected to be used in situations where there is some sort of trauma or injury to the gums that might allow the organism access to the blood stream and therefore they need to be mitigated/eliminated.
5. Testing these items is obviously a completely different world and how, where, when in the process, etc. of testing will need to be determined and justified no matter how you manage the testing itself. Do you test every component on receipt? Can you test components on receipt? Can you test the final device or will you test the environment regularly?
So as you can tell - there are a lot of details that need to be considered around what you are asking and unfortunately I don't think anyone here on the forum will be able to provide you with a silver bullet list of what to do. Happy to help further but I am not a consultant. A lot more specific information would be necessary to provide a more directed answer to your questions.
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Victor Mencarelli MS
Global Director Regulatory Affairs
New YorkNY
United States
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Original Message:
Sent: 22-Apr-2023 19:41
From: Anonymous Member
Subject: Dental material microbial requirements
This message was posted by a user wishing to remain anonymous
Can anyone provide direction for determination of required microbial levels for dental materials, please? I know there is FDA guidance for microbial levels of other medical devices (i.e., ophthalmic devices), but I have not seen any such requirements for dental material microbial levels. If there are none, how are microbial contamination control methods and/or testing determined?