The dental hygienist over time has mentioned a waterpik, but not lately. Between electric toothbrush and daily flossing dentist is happy with my oral hygiene as am I.

Regarding exposure to MAC, I could be wrong but I look at it in terms of viral load. The greater the concentration of exposure to pathogens the more likely you might acquire those pathogens. A swallow of water I'd consider very low exposure, whereas daily hot showers and gardening *might* expose you to greater pathogen loads. There are ways to mitigate exposure while showering (fan off, door open) and gardening (masking, wetting soil). We each need to decide what makes us comfortable.