The only time I've had a dental plan it was offered through my job and I had no choice in the matter. What I do know about them is that you generally will have two options. The cheaper plans that take effect immediately will only cover you by using an in network dentist, and I gather that many dentists choose not to participate in them. I know that mine doesn't. I would suspect that younger ones who are just starting out affiliate themselves with such programs, but well established dentists have no need. Plans that allow you to select your own dentist tend to A. be more expensive, and B. require a waiting period before things are covered. You'll have to pay into the system for a year or two before major procedures are covered.
From what I recall, you had an issue you needed taken care of pronto, and didn't have a dentist or know how to find one. I suspect that would make you a great candidate for one of the discount cards or HMO programs, since they'll narrow down your options considerably. Look at those plans, find one you can afford with decent benefits, and then get the list of participating dentists. From there you can research some that might work for you.
In my case, I'm highly loyal to my dentist, so I'm not looking for anybody new. That said, looking over that site has lead me to believe that a decent PPO program is actually fairly affordable. I will be giving good thought into possibly signing up for one. Glad you brought that to my attention.