I understand but you have to think about things from my perspective. Retaking all the courses and getting A's in them will NOT raise my GPA by that mean (sGPA, I mean). Also, who's to guarantee that I'm going to get an A in all these courses? I'm telling you man, taking 1 year of absolutely nothing but science courses upper-division at a pretty hard school (UCSD) is going to be a killer, rather than a reviver. I looked into John Hopkins' 1 year Biotechnology Masters Online program and it looks pretty legit. Same with a bunch of CSU with masters programs. I honestly think that's my path. The masters itself is pretty you know, looked highly upon. Post-Bacc, just from what I've seen, hasn't produced the same results that the Masters have.
Nobody said it would be easy to get all A's, but you've dug yourself a hole and you need to climb out of it. If getting into dental school was easy, then EVERYONE would be doing it.
Yes, we realize taking 1 year of science courses isn't going to magically raise your sGPA to a super-respectable GPA, but it will raise it, and that's the whole point. Schools are not going to turn a blind eye to a 2.7 sGPA, even if you do have a 1 year masters.
As far taking these courses at a pretty hard science school, I hate to break it to you, but a lot of people on the forums went to hard schools, and they did alright. To be brutally honest with you, at every school there are people who do really poorly, and really well; it is up to you to choose which one of those groups you want to be in.
To your comment about master's being more helpful than post-bacc, you must have missed my point: you might want to do both. Applying in Spring is just going to be a waste probably. You are going to be applying late, when a lot of classes are already filled, most school's deadlines are past, and with a slightly better application.
You have to realize, we are trying to look at this from your perspective and give you useful advice. Yes taking all science classes is going to be tough, but if you can't handle it now, how did you expect to handle dental schools all science, heavy load? You need to show admissions that you are a different person that got a 2.7 sGPA. You need to show them that you have matured and can buckle down and study. Again, you have dug yourself this hole, but if you are dedicated enough, you can get out.
Good luck with whatever advice you decide to take, and hopefully you keep following your dream.