Is state issued medicaid considered PPO?

My children have state issued medicaid, and I recently moved, and got information in the mail to choose a dentist for them. I am attempting to find one, but the website I was directed to use asks if my plan type is PPO, traditional, true blue HMO, or discount orthodontia. I have no clue what any of these are, but I have to find a provider that accept medicaid. Could anyone tell me if the know what medicaid is considered, and if possible why and/or what the others mean so I can avoid this confusion in the future?! Thank you!