USAR dental? Tricare or FEDVIP? Both? Neither? I'm confused.

It's Tricare open enrollment season. I'm USAR with Tricare Select. I need to enroll myself (and my wife if possible) into dental coverage. Tried to do that today and got confused. Is USAR eligible for Dental under Tricare, under the Federal Employees Dental and Vision Plans (FEDVIP), both, or neither? I get different answers depending on where I look. I am going to call Tricare and ask them, but I wanted to check here first.