I don't know exactly what you have done to show adcoms you're interested in dentistry, so here are some tips.
1) Shadow a general dentist and possibly two specialists for about 30 hours each.
2) Try to volunteer at dental clinics in your town or any the university might offer.
3) Schedule a meeting with an admissions member of your university or a dental school nearby and talk to them about what you can do to increase your chances of acceptances.
4) If you haven't taken the DAT, then I suggest you take it in March. If you don't do well on it, you can re-take it in June.
5) Submit your AADSAS application in May or June. For dental schools, early is on time. Start asking for LORs in April, because I know many people have problems with having their LORs submitted early.
Hope some of this helps.