Is Aetna Dental Access PPO or HMO?

I'm trying to sign up for some kind of dental plan and my dentist recommended Aenta (through www.dentalplans.com) and said to make sure they're PPO and not HMO... Problem is I'm looking all over the dentalplans.com site under Aetna and nothing is even mentioned regarding PPO or HMO. If anyone out there has this dental plan can you please let me know if yours is PPO or HMO?