I can't judge your competitiveness without stats, but you applied a little late. Mix ups happen, and they can be very unfortunate. It is really late in the cycle, but think of it this way. You haven't been rejected. You may be on the wait list or possibly accepted! Dental school admissions are hell trust me. Try not to lose sleep over it. At the end of the day only two options will remain. You either got accepted(Awesome) or you got rejected(not as awesome). Next time around improve your application a little and this time make sure all the paper work is correct and early. Some schools are seem to be rather incompetent and a little lazy! Good luck! I hope you feel a little better.
I actually had a similar situation like this happen when a school didn't receive my DAT score even though the other schools did. I was pretty angry at first and wanted my money back from the school, but I learned two things.
(1) I should have been on top of everything and made sure they got my score and had everything on file.
(2) Why would I want to go to a school that seems to have clerical errors. It is only likely a sign of bad things to come.
I won't say which school it was, but mistakes happen hopefully you'll be in. You will find out soon!