https://www.colgate.com/en-us/oral-health/conditions/dry-mouth/dry-mouth-at-night–the-causes-and-management-tips-?fbclid=IwAR2vTVYpnrS88vB_GA6IXEtI5DsaIjRf019yderzqxwHGyaoz-01gQg6Poc
https://www.youtube.com/watch?v=631_a_Oxg3A
https://www.webmd.com/oral-health/ss/slideshow-healthy-mouth