The tablet Christine mentions is XyliMelts. I've only been able to find them at Amazon. They're not a panacea, but help me a bit. I use them on the main treatment side where the salivary glands were most damaged, at time when dry mouth is not letting me sleep well. During the day I get the same results with Trident gum with xylitol.
Peter, age 62 at Dx 3/27/15 Dx T2N2aM0 Tonsilar P16+ G3 SCC 4/6/15 Full PET clear except for above 4/24/15 TOLM tonsillectomy/clear margins. Neck dissection 20 nodes (1 w/cancer & extracapsular extension) 5/28/15 PEG in 5/27 - 7/10/15 Daily Radiation to 66 units cumulative; Cisplatin weekly X 7 8/24/15 PEG out 9/24/15 Full body PET - N.E.D. 12/22/15 CT and physical exam. Continued clear. 3/11/16 Physical exam. Continued clear. 7/12/16 One year post-treatment! CT clear. 7/7/17 2 years post - still clear