I hear adults all the time saying, "I haven't had a cavity in years. I don't need to see a dentist." Sorry. The fact is that after your 20's your greatest risk isn't cavities, it's gum disease. Brushing and flossing (even if you did it daily) aren't nearly enough to prevent gum disease as you get older.
Here's what's happening. There are millions of bacteria in your mouth, and some of them get organized into little colonies, and they love to eat sugar and secrete acid. This acid might give you cavities, but it most likely will travel between your teeth and gums, and gradually separate the gum from the tooth, until you are, as they used to say, "long in the tooth."
Receding gums are bad, and very hard to fix. They expose the tooth below the enamel, which is the hardest bone in the body, and allow decay to reach the softer tooth area below.
But that's not all. Gum disease means that the bacteria have been allowed to travel deep below the gum line, and create pockets of infection. This means you could eventually lose the tooth. Symptoms are bad breath, bleeding when you floss, redness instead of a healthy pink color to your gums, and sensitivity at the gum line.
The only solution is to see a dentist and get cleaned regularly, at the very least every six months. Some people should go even more. (The cleanings are also a lot easier if you go more often.) This removes the plaque, which are the little bacteria villages secreting acid. And if you have gum disease, a dentist can start a program to treat it and allow you to keep your teeth.
50% of the population over 35 has some level of gum disease. My advice is find a dentist you love, and that way you'll go often. Call 1-800-DENTIST or visit www.1800dentist.com, and they'll help you find one. If you suspect gum disease, don't wait until it's too late and you need a root canal or lose the tooth. It won't heal itself, not with some mouthwash or by brushing harder. Get yourself to a dentist. Preachy, I know, but teeth are important.