Question About Dry Mouth

I’ve suffered from dry eye syndrome and dry mouth for almost 20 years (I’ve also been on anti-depressants) and, throughout that time, I’ve visited many dentists and endodontists due to chronic dental problems - numerous fillings, root canals in all my molars, and three dental implants (3 molars had to be pulled). And not one dentist or dental hygienist has ever mentioned the correlation between dry mouth and tooth decay or educated me about it. I just recently found out about something called Sjogren’s syndrome which attacks the salivary glands in the mouth and oil producing glands in the eyes and a medicine called Salagen (salagen increases saliva production in the mouth and can help with dry eyes). Why don’t dental professionals (or dental hygienists) educate you on the underlying things that could be impacting tooth health? It seems really odd to me. If I were a dentist and starting seeing a patient with a mouth full of fillings, root canals, and crowns, I’d certainly ask the patient probing questions about their dental cleaning habits. But if he/she conveyed that they had dry eye syndrome and constant severe dry mouth and I determined their dental cleaning habits were not an issue, I’d educate them on the adverse affects of dry mouth on teeth, ways to combat dry mouth (Biotene, xylitol gum, etc) and make them aware of the drug Salagen and the disease Sjogrens Syndrome (and suggest they go see a Rheumatologist to get checked out). Any insight you can provide would be much appreciated!