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Tips to Avoid a Refuse to Accept Letter When Submitting a 510(k) Application

Common RTA Triggers

Michael Adjodha, who evaluates 510(k) submissions for dental devices for the FDA, said there are several ways in which an application may trigger an RTA letter.

  • Non-Identification of Prior Submissions: If there were none, write none in box 1 of Section F of the premarket submissions cover sheet (FDA 3514).
  • Application Missing Forms 3654
  • Lack of Device Description with Mechanism of Action: Restating the indications for use as the mechanism of action is not sufficient. The FDA needs to see an explanation for how the device achieves its intended use.
  • Lack of Engineering Drawings or Illustrations of the Device
  • List of Components is Incomplete and 510(k) Numbers of Each Previously Cleared Component are not Identified
  • Analysis of Similarities and Differences: The application must demonstrate that differences do not represent a new indication or intended use—or, that the differences don’t raise new questions of safety or effectiveness. A related problem occurs in a comparison table that uses words like similar or identical to describe the parameter of the subject device in comparison to the predicate. It may make the table a little longer but give the description of the subject device’s characteristic and let the reviewer decide that it is identical or similar to the predicate’s characteristic. In this case, identical means same supplier, same materials and colors, same chemical composition, same catalog number, etc.
  • Incomplete Labeling or Missing Instructions for Use
  • Sterile Components (if included) are not Identified in the Submission
  • Shelf Life Information is not Included:  If  there are none state the reason.
  • No Biocompatibility Information: If there is none, justify why it is not required.
  • For Patient-Contacting Materials, Failure to Give a Complete Identification of Materials: The chemical identity should be complete. All colorants must be identified. The percentages of each ingredient must add up to 100%, or thereabouts.
  • Lack of Relevant Performance Data to Establish Substantial Equivalence: If you’re unsure what kind of performance data you need, contact Dr. Susan Runner* and ask.

Ways to Improve 510(k) Acceptance

During the meeting, Adjodha and other FDA staff offered several suggestions for DTA members to decrease chances of receiving an RTA.

  1. Make sure you properly characterize the type of body contact. If you’re using bar stock, milling it with lubricants, cleaning and etching the finished device, conduct biocompatibility tests on the finished product to prove exposures during the manufacturing process haven’t altered the device.
  2. Buy materials, such as polymers, from suppliers. The FDA wants to see a complete chemical composition of your product, or reference to another cleared device using the same, identical materials. If you can get the suppler to provide 510(k) numbers for similar products, cite those numbers if the supplier won’t give you the chemical composition because they consider it proprietary. If they won’t do that, because they consider it proprietary information, ask the supplier to provide the chemical composition in a confidential file to FDA. That way the proprietary concern is covered because only FDA and the supplier have access to the information. If the supplier agrees, talk with them first to see just what they are going to include. The reason for this is to make sure FDA has the information it needs when they review your 510(k). If the supplier won’t agree to this, ask them if they will at least provide you with the table of contents for the file.
  3. For the material identity, include chemical names, CAS numbers and all colorants with their percentages. Using colors listed in the list of acceptable colors in 21 CFR Parts 73 and 74. Click here to view the CDRH webpage on colors in medical devices. While it is not mandatory that only these colors be used, FDA commented that those contained in the two lists in Parts 73 and 74 are best.
  4. Use headers and footers to add the section number to each page, along with page numbers.  Do not include pdf files in image format.
  5. Include an annotated copy of the RTA checklist and add page numbers to each required item.
  6. Support all claims. If you aren’t sure what constitutes supportable information, contact Dr. Susan Runner* or send in a pre-submission form. They are free, they get logged into the division database and tracked—and therefore must be responded to.
  7. Clearly explain how your device is similar and different than the predicate. Include an explanation for why the differences don’t affect safety and effectiveness.
  8. In the 510(k) summary, list one, and only one, predicate device.
  9. Include summaries of test reports even when copies of the reports are included in the submission. In the summary for each test report, discuss how the results support substantial equivalence and safety and effectiveness.
  10. The 510(k) summary should include tests relied on to support substantial equivalence.
  11. The FDA suggests using the following format when you put together a response to a written question during the review.
    • Restate FDA’s Question
    • State Your Response
    • Include the pages in the 510(k) that have changed due to the response. Highlight the chances so that they stand out for ease of review. Change the font color for changes made during each round of questions, if there are more than one.
    • Consider using a pre-submission form well in advance of submitting your 510(k). They can take significant time to move through the FDA’s tracking process, get reviewed, and achieve a satisfactory resolution.
    • Make use of the device advice tutorial. It has links to most of the information needed to prepare and submit a 510(k).

If you have a simple question, contact the dental division’s Michael Adjodha* or Dr. Susan Runner.*  If the question is complex, needs extensive explanatory or requires supporting information that the reviewer has to look at before giving an answer, complete a pre-submission form.


*For contact information, please call the DTA office (703) 379-7755.