Improving the fit of filtering facepiece respirators

Aims To assess the effectiveness and acceptability of smartphone customised frame technology to improve the fit of disposable filtering facepiece class 3 (FFP3) respirators for dental staff who previously failed fit testing. Method In total, 20 volunteers who previously failed FFP3 fit testing were recruited to use smartphone technology (Bellus3D FaceApp) to have a 3D-printed bespoke face frame produced for them. They underwent qualitative fit testing with and without the frame with two freely available disposable FFP3 respirator designs (mask A: GVS F31000 Segre folded model; mask B: Valmy Spireor). The order of testing was random. Ease of use of the smartphone technology and the comfort of the frame were determined by questionnaire. Results Fit test passes increased from 5% without the frame to 70% and 95%, respectively, for masks A and B with the frame (p <0.01). Very few participants reported using the technology as difficult (n = 1/20) or the frame uncomfortable (n = 3/20) or difficult to wear (n = 0/20). Conclusion Customised frames produced using smartphone technology improved qualitative fit test pass rates for two commonly available FFP3 respirators. Using smartphone technology for frame design, wearing a frame and frame comfort levels were all acceptable to the majority of participants.