You’ve brushed your teeth the same way for so long, it’s second nature. But are you doing it at the right time? For the right amount of time? The right way? With the right amount of toothpaste? More than 1 in 4 adults in the U.S. have untreated tooth decay, and half of everyone over 30 have signs of gum disease. Time to get a handle on mistakes that affect your mouth.

Get out the stopwatch: Your brush time may be shorter than you think. The American Dental Association recommends that you brush a minimum of 2 minutes each time to remove a decent amount of plaque. If you have devices in your mouth, like braces, a bridge, or implants, add extra time to gently clean around areas where food gets trapped.

Once in the morning doesn’t cut it: It’s important to brush your teeth twice a day to remove bacteria and plaque. Think of your teeth like a plate. After you eat, your plate won’t be clean if you just rinse it off. It takes scrubbing with dish soap and a sponge. The surfaces of your teeth attract food, and only a toothbrush and toothpaste will get into the nooks and crannies.

For the first 20 to 30 minutes after you eat, your mouth becomes slightly acidic and your tooth enamel weakens a bit. If you brush right after you eat, you run the risk of wearing down your enamel too fast. Less enamel means it’s easier for bacteria to settle in and cause more cavities and infection. Wait at least 30 minutes after you eat to brush, or if you’re in a hurry, rinse with water or use mouthwash to neutralize the acid.

Place your toothbrush on your teeth, then tilt it up a bit so it’s at a 45-degree angle to your gums. Then move the brush head from tooth to tooth, using a small circular motion. This goes for the outer surfaces of your teeth, the inner surfaces and the tops or chewing surfaces as well. For better access, try using your left hand to brush the right side of your mouth and your right hand to brush the left side.

No matter how perfectly you brush, if you don’t floss, you miss half the surfaces of your teeth -- and plenty of plaque that can cause cavities and gum disease. Plaque is a sticky film full of bacteria that feeds on the leftover food in your mouth. It gives off an acid that eats away at your teeth and can harden into tartar that only a dentist can scrape away.

Your tongue is the floor of your mouth. It helps you speak and swallow, and it also traps bacteria that leads to bad breath and tooth and gum decay. Use your toothbrush to clean from back to front a few times after you brush, but take it easy: Your tongue is covered in papillae, or tiny bumps that help you sense taste and texture.

Whether you use a manual or powered toothbrush, the most effective way to clean your teeth is by repetition, not force. Just exert the same amount of pressure you’d use to ring a doorbell. Too much pressure wears down your enamel and causes recession, or shrinkage in the tissue that connects your gums to your mouth.

In commercials and print ads, toothpaste always covers the bristles of the brush, from beginning to end. But adults only need a pea-sized amount, or half the length of a standard toothbrush. The fluoride in toothpaste is a mineral, and too much of it can change the shape and structure of your teeth.

To keep your toothbrush as clean as possible, rinse it to make sure all the toothpaste and debris are out of the bristles and store it upright where it can air dry. If you store it near other toothbrushes, make sure they don’t touch. Don’t cover it, or store it in a container, because bacteria love to grow in moist environments.

The lifespan of a toothbrush is about 3 to 4 months. After that, the bristles become frayed and don’t clean your teeth as well.

You’re probably most motivated to clean the front of your teeth because it’s the easiest to access and the part other people see. But the tops and backs of your teeth -- the part that faces inside your mouth -- are just as vulnerable to the 500-700 species of bacteria that live in your mouth.