Someone who is challenged dentally. This would be someone with severely crooked teeth. This could also be someone missing teeth. Rotting teeth also counts. These people usually haven't ever gotten their teeth cleaned.
Person 1: Dude did you go to Ronny's house?
Person 2: No, his dad is so freaky he's Dentally Challenged.\
Person 1: Was he a meth addict?
Person 2: Yeah Dude, I think he is.