Hey
I got in after 3 years for this upcoming year. Got in at UConn, which isnt exactly a pushover school...not to mention the fact that it IS a state school and I am from Tennessee. I also got interviews at every school to which I applied. I am not saying this to let you know how hard core I am, but only so that you can see that it is doable.
I finished my OChem my soph. year, and am just finishing physics to complete my requirements. I took the DAT this last summer (summer after soph. year) and got a 21 (with much studying). My GPA was 3.7/3.5 sci. I had a good deal of experience in a dental office. At the interviews, most of the time I was respected...one might think that they would ask whether I was mature enough to go into dental school having not even turned 21, but, instead, I think the committees know the work required in order to have a chance of getting in after three years. They know that you really had to have your crap together or you didnt stand a chance against the students with degrees. You do have to stand out, but not so much that it is ridiculously hard. I didn't feel I got grilled any harder than any of the other students I talked to.
As far as whether it will hurt you applying early and being rejected, the answer is a resounding NO. In fact, schools really like that you came back even after being rejected-it shows that you didnt give up and go into podiatry or something. Call the schools yourself if you want to know how they feel...I did, and they said it could never reflect badly.
In fact, my state school actually told me that if I was rejected the first time I applied, they would tell me EXACTLY under what conditions (ie take DAT again, repeat classes, etc.) I could be accepted the next year and guaranteed my entry the following year if I did the things they asked. I didnt have to deal with this because I got in the first round, but, am confident I would have actually had a distinct advantage over most aplicants the next year had I been rejected.
The bottom line is, you've got nothing to lose and everything to gain. If you dont get in the first time, you have an advantage the next year, and if you do get in, well, there you go.
Know though that the stats are stacked against you...only 2% of all matriculated dental students do not possess and undergrad degree. Don't think it will be easy, but, go for it.
Just for the record...got accepted at UConn, UPenn, Nova, Kentucky, UNC Chapel Hill, Tennessee, and turnded down interviews at others...so, there are a variety of schools that will look at you. Dont apply to Tufts; they dont accept 3rd year people.