Sleeping on your side reduces dry mouth because when you sleep on your back your mouth falls open and makes dry mouth worse. Sleeping on your back increases mouth breathing. I keep a spray bottle of Oasis by Sensodyne, oral demulcent moisturizing mouth spray for dry mouth, by my bed and use it during the night. Also I rinse my mouth many times a day with water with a little baking soda in it. Keeps the mouth clean. Dry mouth can lead to infections such as candida (fungal infection.)

Barbara in Houston, SSC upper lip, perineural invasion