Saliva rinses the mouth and cleans the teeth between meals, neutralizing acids produced by bacteria and allowing the teeth to remineralize. Decreased saliva flow results in dry mouth (xerostomia), which promotes caries and periodontal disease.
Wolff A, Joshi RK, Ekström J, et al. A Guide to Medications Inducing Salivary Gland Dysfunction, Xerostomia, and Subjective Sialorrhea: A Systematic Review Sponsored by the World Workshop on Oral Medicine VI. Drugs R D. 2017; 17(1): 1-28.