Should I pick preferred provider for dental or managed-care dental?

I need a lot of work done, root canals and filling. It is going to cost a lot. I have a chance to get on dental for eight months and I need to know what will be cheapest.
--------------------
It depends on if you care who does the work or not. If you want a specific dentist, pick the preferred care. I don't know about the cost aspect, but it always scares me when someone has to go to a certain group of doctors that are picked for the plan. I want quality not just quantity for you.
Source