Possible tooth worry, not eating hay/chewing, slow eating/drooling

Will is about 9 years old, and has recently altogether stopped chewing toys and stopped eating hay. He has been eating his regular food, but very slowly, and drools. Eating the occasional raisin is also a slow process, with drooling. He's been more friendly too lately, coming up to the cage for attention when I'm walking by, more comfortable being held, etc. He seems generally happy as far as I can tell, but so did our other chin Jack until he stopped opening his eyes because of ingrown...

Possible tooth worry, not eating hay/chewing, slow eating/drooling