What is the ruling on placing a date pit to stimulate saliva flow during fasting out of necessity for work that requires much speaking, and due to a problem in the vocal cords that causes pain when the throat is dry?

Placing something in the mouth from which no parts dissolve does not invalidate the fast, but it is disliked, unless parts from that kernel dissolve and reach the throat. If one tastes its flavor in the throat, the fast is broken. It is forbidden to chew something from which parts dissolve, as this would mean intentionally allowing something to reach one's interior.