I think you're right yellowted. Usually the hygienist doesn't use that device except for one area. I think she had others waiting and that's why she used it all over my mouth. I could feel the mist all around my nose, so its makes complete sense if I breath this..... I might get sick. From now on I'm going to request the cleaning be done manually. Dentists also are supposed to check and clean the water lines and tubing of those instruments regularly. My dentist is a friend of ours and a nice man so I don't want to complain. I will mention I got sick the next time to the hygienist and request it be done manually.