I had a tongue depressor in my mouth through the mask during IMRT. It had a soft square type thing on it to bite on. Saliva swallowing was a problem at first, but after a short while you will lose your swallowing reflex and your mouth will dry out and it won't be that big a deal. Toward the end you might have a mucous problem and at that point you may have to stop half way through treatment to cough it up. That's what I did. My sessions were actually 45 minutes.