Although others may choose to post what they had....I personally think it is better that you do not know what the problem that they gave.
Personally, when I interviewed last year, I knew what the case was because my roommate had gone through the interview previously and had let me known what it was about. Knowing the problem, and solution was honestly slightly distracting, as I had to pretend like I didn't know about the case, while at the same time being involved in the process.
Without giving anything away, it is a really basic problem that requires no dental knowledge, or even scientific knowledge for that matter. Although I do not know what exactly the admissions people are observing for, it is my belief that they are looking to weed people out that either have no personal skills, do not function at all in this group setting, or have some other problem that is manifested very obviously through this process.
So, sorry that you're not going to get what you're looking for from me. This is just my personal opinion, so others might not agree and choose to post. But like I said previously, it will not really help you excel in the interview, and I believe it may hinder you. Regardless, if you have any questions about the school, pbl process, etc....don't hesitate to pm me.