The only time you should ever get tricare Dental is if you or your family are having major, long term work done that either isn’t covered by the SWA plan (for example, a bunch of crowns that have been previously done and therefore aren’t covered) or if you have a kid(s) in braces to get a double braces payment. You are required to keep it for 12 months after you sign up, and it isn’t cheap.
Regular plan Dental isn’t great, but it is pretty good and well worth the extra money in your pocket.