At NADL’s V21 conference there was much discussion and many questions related to FDA’s rules for CAD/CAM milling of implant abutments. As a follow-up to JDT’s January article the following are answers to the most common questions that were asked.
Why did NADL enter into the conversation on CAD/CAM milling of abutments?
Over the past year the FDA has increased its enforcement activity relating to the CAD/CAM milling of implant abutments. FDA has sent compliance letters to dental laboratories and milling centers. In January the FDA sent a warning letter to a manufacturer (and 510(k) holder) in part for marketing abutments for uses that were not 510(k) cleared. In addition to FDA’s increased enforcement activity, some market participants began to publicize aspects of FDA regulatory requirements relating to CAD/CAM milling of abutments for marketing purposes.
If a lab designs an abutment and sends to the manufacturer, what if it comes back to the lab and the lab retouches it; are we still in compliance with the applicable regulations?
Adjusting the custom abutment with a hand piece is permitted as long as the adjustment is within the design parameters. Adjustment using CAD/CAM is not permitted.
Is a lab “designing” an abutment when they use software to create a design file and then send the design file to the abutment manufacturer for milling?
The FDA recognizes that when a lab sends a design file for a patient specific modification to the abutment manufacturer/510(k) holder, that as part of the abutment manufacturer’s cleared process all design files will be checked prior to milling to determine if the design is within their cleared design parameters. If the design received exceeds the design parameters they will send the design back to the lab explaining that they cannot mill that design.
Once the abutment manufacturer sends the custom abutment to the lab, within the design parameters minor modification by the lab is permitted using a hand piece but the lab may not redesign the abutment and may not make changes using CAD/CAM.
Stock abutments – how much can you modify?
Stock abutments aren’t supposed to be modified. The design of the stock abutment is cleared as part of the 510(k). If a lab modifies the stock abutment then they are creating a new design. Some small adjustments done by hand in a lab are permissible. However, if you take a straight abutment and change it enough so that it’s an angled abutment, this is a new design and would not be in compliance with FDA regulations.
Abutment blanks – lab milling?
Labs can mill the top of an abutment blank by hand without a 510(k). FDA appears to be going after sites offering to CAD/CAM mill the collar and post from a blank as well as sites that are selling blanks that claim labs can put in them in a wet mill, as that requires registration with FDA as a manufacturer and a 510(k) clearance.