Sir, the use of 3D face scanning in dentistry is nothing new; clinicians and dental laboratories use this technology as an integral part of diagnostic, surgical and restorative treatment planning. During the COVID-19 pandemic, this technique is being used to produce a bespoke frame to achieve a facial seal for disposable FFP3 masks, in circumstances when achieving a seal has proved challenging. Being unable to 'fit test' dental clinicians despite trying various makes and models of FFP3 masks was the driver to explore this solution.

We used the Bellus3D face-scanning app, downloaded from the App Store. The 'Mask Fitter' option was selected to produce a 3D scan of the face. An STL file for laboratory printing produced a standard frame (Fig. 1) which fits over the FFP3 mask to produce a tight facial seal. The frame is held in place by attached elastic straps (Fig. 2). This technique has resulted in individuals subsequently achieving a passed fit test for a FFP3 mask which has previously failed to produce an adequate seal on its own.

Fig. 1
figure 1

Standard frame produced by an STL file

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Fig. 2
figure 2

The frame is held in place by attached elastic straps

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This is a cost-effective option when compared to purchasing a powered air purifying respirator (PAPR) which would be the only other alternative. The total cost of this face-scanning solution including purchasing the app, STL files, laboratory fees and elastics was around £25. Simple steps to follow:

  1. 1.

    Download the app https://apps.apple.com/us/app/bellus3d-faceapp/id1352268131

  2. 2.

    Open the app and place your face in the red demarcated area

  3. 3.

    This produces a 3D scan of the face. Choose the 'Mask Fitter' option on the menu bar

  4. 4.

    Choose frame type

  5. 5.

    Choose Export (unless you have your own 3D printer)

  6. 6.

    Pay the Export fee through the App Store

  7. 7.

    Email created STL files to the laboratory or 3D printing centre

  8. 8.

    Purchase elastic roll with eyelets to fit the frame to the face

  9. 9.

    Conduct fit test with FFP3 mask and frame in place.