I remember there were a lot of Ashkenazi Jews in high school. I have noticed that three girls had black teeth. When I asked why their teeth got black, I was told because of syphilis. The crazy thing is other Jews kept having sex with them, despite syphilis and black teeth. These Jews were smart enough to study, but had complete lack of self preservation and disgust instincts.
Later I have met other people with blacked teeth in university and the gym. They were still sexually active despite disgusting blacked teeth. I'm not sure if they were also Jews, but they were obviously not normal.
Sad but face reality