Gunny,
In corporate your pay is directly correlated to your production (e.g. 25-33% of what the office collects on your patients, usually towards the low end of that range). The corp's incentive is to maximize your production, which also happens to maximize your pay... so in that sense your personal welfare aligns well with theirs. Fairly large earnings are possible.
Problem is twofold:
1. For most mere mortals, $ production is INVERSELY correlated to quality of work. I.e. to crank out $6 or $10K+ worth of dentistry a day, you will be rushing and may start to lower your personal standard of what's OK work. Especially early in your career when your skills are developing and it takes you longer to do anything. Most patients will never know the difference (except they will think they have "bad teeth" because they're always needing more work done). There is a wide range of quality among different dentists' work, and I have seen some SHOCKINGLY crappy dental work come out of corp chains. To be fair, you could say the very same about some private offices. The main difference is that in corp nobody in the office is going to be all that concerned about the quality of your work (it's your license on the line, not theirs), whereas in a good associateship the owner dentist ought to care some because his name is on the door, and as an owner yourself same thing. So it doesn't have to, but corporate has the potential to make you sloppy.
2. Production is also correlated to how much dentistry you can talk patients into "needing." They really don't know -- at the end of the day they just need to trust your word. This puts a high ethical burden on every dentist, one that some people handle better than others. In a private office, your conscience (however strong or weak) is bolstered by the need to protect your reputation over the long haul: your name is on the door. Most patients will never know the difference, but a few will catch on. When you work quasi-anonymously for Big Smiles Dental Inc or whatever, your conscience is going to be more sorely tested because (a) your name isn't on the door so what do you care, and (b) in many corp offices the office manager, your boss, and everybody else up the chain from you will be actively pushing you, sometimes pushing you very hard, to diagnose more dentistry and sell bigger treatment plans.
At the risk of offending, I will venture (from personal observation over years and years in this field) that some very financially successful dentists are either sloppy dentists, con artists, or both. Not uncommonly, either. IMO corporate dentistry can more easily seduce you into one or both camps.
Still not a bad way to start a career, and not every corp chain is the same - far from it. Some are quite good. But some others will IMO ruin you unless your personal standards are high.