I find it extremely hard to comprehend insurance system. Maybe that's the whole point. Insurance carriers do not want us to know.
To my understanding, there are 2 big categories: HMO and PPO. PPO is called "fee for service". You bill the insurance for services you perform and get paid according to the contract amount or fee. If you're out of network, you can also bill the patient for the difference.
HMO is the managed care (capitation). The member picks a dentist from the network and can go see him only, no other dentists. The insurance company pays the designated dentist certain amount of money, say every month per patient. If the patient doesn't have dental problems and not see you often, you get paid for doing nothing. HOWEVER, if the patient has a lot of work to be done, you'll be doing all that work at the fixed amount of money (capitation, some pays $5/person, some pays $35/person) you receive from the insurance. The insurance will not pay you extra for doing that. That sucks. Dentists would not want to see their HMO patients and might under-treat them.
NYC tried to cut the medicaid cost by converting from PPO to HMO. Now many medicaid members have to pick an insurance carrier like HIP, Health Plus, Metroplus, Health First, etc. These insurance companies put the members under HMO including dental. However, it didn't take too long for dentists to cancel their contracts with HMO companies and stop seeing HMO patients. Do you think it makes sense for small practices to receive $9/person (that's what HIP pays) and do 3-4 root canals and crowns? No dentists in their right mind wanted to do that. Now those insurances offer PPO dental. Even though their fees are low, it's still better than capitation money. I think it was great for dentists to turn down HMO's and not be bossed or intimidated by them.
Hope that helps. Correct me if I'm wrong.