Guy asked me out for a second time and I don't want to go

How do I turn someone down? I went out with this guy I met on Match last week and it was great he was nice and kind of cute and we had good conversation the only issue is he is missing his front tooth! Like omg, he told me how it happened but still I just can't handle that like I am a teeth freak and I just feel like I can't go out with him but he asked me out for tonight and I said yes because I don't wanna be mean.  I'm gonna go but I need to cut this off somehow.  I can't date someone with a missing tooth and I know he will be getting it fixed soon but it needs to be done now. I can't kiss a person with no front tooth it's just weird. I don't wanna be mean but I just don't know how to handle this?