She could also try Biotene toothpaste and Biotene mouthwash (available at most WalMart, Walgreens, Rite-Aid, etc) and see if that brings relief. My dentist also says to buy lemon drops (sugar-free!) to cause me to produce more saliva from the sour taste. All of this seems to do the trick - good luck!
Lupus and RA and LOTS of Medications!