Most insurance plans have so many different elements to them, and most insurance companies have dozens if not hundreds of variations in their plans. And it's very hard for dentists to keep up with how their patients are covered, and so it becomes the responsibility of the patient to keep track of their coverage.
Now is the time of year when you should be looking at your plan, and if you need some dentistry, get to your dentist before the end of the year and get it done. While I disagree with the way dental plans control your treatment, if you have coverage you might as well take advantage of it, even if it's inadequate.
If you don't have a dentist and you have coverage at work, you're neglecting an important part of your health. While it's a bit bizarre that health insurance stops at your lips, not much is going to be done about that anytime soon. Despite this, the health of your teeth and gums is directly tied to your overall health. Don't wait until it hurts. That's a sign you waited to long.
Use your insurance--it's there to keep you healthy. Find a dentist who takes it and who is also someone you think you'll like going to. If you love your dentist, I believe you'll go as often as you should.