Our tabby, Louie, has front canine teeth that protrude downward more than usual. When he rubs his face/cheek on you, you can feel the tooth scraping over your clothing or skin. Our orange-guy, BooBoo, had a 'dropped fang' ... and eventually that tooth fell OUT. His issue *was* a dental issue. Boo now has no teeth, except for the tiny ones in front and maybe 2 molars on one side at the very back.
I think that look is more noticeable in black cats because of the color difference; black-fur/white-tooth.