salivary stones
Salivary stones would certainly be a temporary bar to flying if they caused sufficient symptoms to be a significant distraction from the primary task of controlling the aircraft safely. Similar principle to renal stones, though unlikely to be anywhere near as horrendous as renal colic !
Some salivary stones might be passed spontaneously (again, like kidney ones ! ) but others might require surgical removal. In an aviator any operation requiring a General Anaesthetic requires ten to twelve days' grounding, simply because of the GA.
Finally, some simple tests might be done to try to identify any predisposition to stone formation in future ( eg Calcium etc ).
Overall, very unlikely to be a LONG-TERM problem for any pilot !