The best way is to ask your dentist. You can also check the provider directory for each plan at www.opm.gov/healthcare-insurance/dental-vision/plan-information/. However, the plan’s directory may not have the most recent updates, so you should always verify participation with your dentist.
Continued participation of any specific provider cannot be guaranteed. You should choose your plan based on the benefits provided and not on a specific provider’s participation. You cannot change plans outside of Open Season because your provider is no longer in-network.