Bottom line
The TRICARE Dental Program (TDP) is a voluntary dental plan you can buy for yourself and your family if you are a Ready Reserve member. To enroll you need at least 12 months of service remaining, and you commit to an initial 12-month period. After that, you stay on month to month as long as you stay eligible and keep paying the premium. The premium comes straight out of your drill pay and shows up on your LES each month.
What it means for you
This is dental coverage you pay for, not automatic. If you want it, you sign up through the TDP website, your local uniformed dental facility, or your local health benefits/installation point of contact. There are four ways to cover people: just you (Sponsor only), one family member (Single Premium), more than one family member (Family Premium), or you plus family (Sponsor & Family Premium). The cost is pulled from your pay one month at a time. If your pay one month is too low to cover the premium, the system does not stack it onto the next month, so watch your LES to confirm the deduction actually went through.