For many years i've had this coating of white gunk on my tounge. I suspect it's bacterial, since I seem to be very susceptable to canker sores in my mouth if I eat too much junk food (sugar in general). My doctor told me to rinse with salt-water, but that only helps keep it down, it won't get rid of it. Also, once in a while the back of my tounge gets sore, and that's where it's most concentrated. Anybody know what this is and/or how I can get rid of it?