I would like to know if eating lots of roasted and salted sunflower
seeds in the shell (approximately one 2.5 oz bag a day), is good, bad
or more or less neutral for me. I don't really care about the fat and
salt from a nutritional standpoint but am curious about what, if
anything it will do to my mouth. Is it particularly good or bad for my
teeth? Breath? Etc.

My guess is 2.5 oz per day is nuetral for breath, teath and mouth.  Neil

I would think that too much salt in your mouth can scar the gums and
the inner lineage of your mouth which is very sensitive to high salts
and high spices. So, anything in excess is not good, I would assume!