I graduated as a EE, worked as an IT consultant doing business analysis and software development for almost 3 years before applying to d-school. I was able to do my d-school pre-reqs part-time and work full-time.
I think that ppl coming from a working background with some real world experience definitely enhances your application.
1) you should have enough maturity to manage your time appropriately (hence you see many post-bacc ppl getting much better grades than their undergrad)
2) you should pick up valuable ppl and management skills that will help you a) relate to your patients b) manage your practice
3) as pumpkins90 mentioned, it shows true dedication that you have explored alternative career paths, chosen dentistry, and have enough drive and determination to switch over to dentistry.
My gpa was dismal in undergrad; I was able to bring it up in my post-bacc work (it's still dismal, though). The fact that I was able to work and do well in school showed the d-schools that I had enough discipline and smarts to make it. Plus I was able to pay down a significant amount of my ug school debt, so that was another area that I was able to demonstrate discipline and maturity. Anyways, I was accepted to UTHSC-SA, still waiting on UTH, rejected from Baylor. Plus, if you're working, you always have a backup plan if things don't work out.
Best of luck to you - pumpkins90 and I have been through, so if you have a true desire for dentistry, best of luck to you...