Warning: This post began as a response to your question but I quickly went on a huuuge tangent.
I'm also extremely interested in MBA/DMD programs. I am a business undergrad, PMI certified project manager (lean/six-sigma, etc.) and am really going into dentistry with a business first mentality.
The goal would be to find and exploit opportunities in today's industry. I think this is especially valuable especially because, as corporate and DSOs become more and more prevalent, opportunities are sure to abound. By my reasoning, an MBA would definitely make it easier to get into this side of dentistry.
Even if that doesn't work out, I definitely see myself starting (or at least attempting to start) a chain of offices. I would say if you are also business inclined and are thinking similarly along these lines, DO NOT WAIT until after dental school (or even until starting dental school) to begin going down this path. Much more valuable than an MBA is a connection in the right place at the right time. Contact industry leaders; I have found that successful consultants are often willing to spend their "free consultation" with me. I haven't been too successful in securing a long-term mentor yet but imagine that that might become easier towards the end of school.
I have 2-3 relatively young successful entrepreneur aunts and uncles (mid 7 figures) and they have asked me many times why I wouldn't rather just borrow several hundred thousand from them and start developing successful practices now, saving myself four years of debt and school (my dad's also a dentist so there's some familiarity). My rationale for going to dental school is that starting and managing practices becomes not only infinitely easier (first-hand experience, moral authority when coching/training associates, etc.) but much cheaper when you can put in your own hours building it, especially early on. I'm not at all afraid of putting in 5-6 day work weeks, 7-7 for the first several months (this is essentially what you do for several years as a business grad in corporate America anyways) but paying an associate(s) to do that kind of labor gets expensive quick especially because dentists are used to a very luxurious schedule (see: 4 day work weeks, !?) relative to other professions. Also, from firsthand experience, for DSOs to be truly successful, maximum (and I mean MAXIMUM) efficiency is essential in both training and operations. IMO, it would be difficult to compete with and beat out other competitors (who are seeking to do the exact same thing) without having firsthand experience with operations, case presentation, procedures, etc. You need to have a significant competitive advantage and that, I imagine, would be difficult to develop from the outside looking in.
Of course, there are a few business men turned dental moguls sans-DMD/DDS but from what I can tell EVERY ONE started their DSOs in the 90s, when corporate dentistry was brand new (see Bob Fontana) and competition was non-existent. There was so much time to learn and be sloppy; you could afford to make mistakes and learn by trial and error. Today, a new corporate office opens literally every 4-6 months in my small hometown (pop. 40,000). Dentists open new practices in the wrong location and (due a lot to inefficiency, I think) can go bankrupt within 2 years if they don't cut their losses.
Grads looking to be solo practitioners are in for a rude awakening if they think what worked for the previous generation will still be competitive for them, imo.
Anyways, all of this is to say that an MBA is only as valuable as your goals and motivations are. If you are not already thinking (or beginning to) like a businessman/woman, then the business side of dentistry probably isn't for you. Out of almost all graduate degrees, MBAs have both the highest ceilings and the lowest floors.
