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IMPORTANT: The filtration efficiency and protective ability of a face mask is compromised when the mask becomes wet, torn or dislodged. In general, the higher protection value of a mask the longer it will maintain filtration; however, there is no set rule for how long a mask should be worn as it depends on humidity levels, respiration rate, nasal discharge, talking, etc.
A face mask should be worn for only one patient procedure or visit. If a mask gets wet or soiled it should be replaced immediately.