context: You practice good dental care: You brush your teeth, floss fairly regularly, and see your dentist twice a year for checkups and cleanings. Good for you! But you're probably also engaging in one or more bad habits that can undermine the good ones and compromise your dental health. Here's our list of five of the worst dental habits, why they're harmful, and what you can do to stop them. You slurp down an ice-cold soda or iced tea and then crunch, crunch, crunch the leftover ice. What's the harm? The brittleness and cold temperature of ice cubes can actually cause teeth to fracture. They can cause microscopic cracks in the surface of the enamel, which could lead to bigger dental problems over time. Crushed ice is less harmful than bigger cubes, but it still doesn't get the blessing of most dentists. Right up there with ice cubes are popcorn kernels, which can also put undue stress on a tooth and cause it to fracture. Some people keep the pits of fruit such as peaches, apricots, and plums in their mouth to suck on and then crunch on. Sipping sugary soda throughout the day is another bad habit, research suggests. The constant exposure to sweet and acidic beverages can foster tooth decay. Be mindful of these practices when you eat or drink. Switch to crushed ice in drinks and when eating snacks eat something that's healthier to chew, such as baby carrots. Sip soda through a straw to minimize soda exposure to your teeth. Be sure the straw is positioned toward the back of the mouth, not resting against your teeth. Dentists report that patients rely on their teeth for a number of odd jobs: to tear open a bag of potato chips, uncap a bottle of nail polish, pull out a watch stem, straighten a bent fork tine, or rip a price tag off a piece of clothing. This can be hard on your teeth, traumatizing them or causing the edge of a weakened tooth to chip off or even fracture. Think about what you're putting in your mouth before you use your teeth as tools. And keep simple real tools such as a scissors and pliers handy to do the dirty work and let you maintain good dental health. Whether you grind your teeth during the day, at night, or both day and night, it wears them down. Although teeth grinding can be caused by a number of different reasons including stress and anxiety, it is more likely caused by an abnormal bite or by missing or crooked teeth. Your dentist may suggest wearing a mouth guard for teeth grinding at night. Custom models made by your dentist cost more than over-the-counter ones, but they generally fit better and work better, too. Sometimes, it helps simply to be aware that you are grinding your teeth. If it is caused by stress, consider an exercise program or counseling. You may also want to try cutting back on foods and drinks that contain caffeine; reduce or avoid alcohol consumption; don't chew on pencils or anything else that isn't food; if you notice that you clench or grind your teeth during the day, position the tip of your tongue between your teeth to train your jaw muscles to relax; and, relax your jaw muscles at night by holding a warm washcloth against your cheek, in front of the earlobe. Some people think the firmer the toothbrush, the better. This isn't so, especially for older adults. With age, the gums push back and the roots of the teeth become exposed, often increasing sensitivity. The root is covered with cementum, which is worn away more easily than enamel. A brush with too-firm bristles may irritate the gums and lead to sensitive teeth. Ask your dentist or hygienist what toothbrush might be best to maintain your dental health. Some people brush, floss, and rinse their teeth regularly, but not often enough. You should aim to brush twice a day, and be sure to replace your manual toothbrush or electric toothbrush head every three or four months. Flossing teeth should be done daily, too. If you aren't sure if you floss properly -- and dentists say many people aren't -- ask your dentist or your hygienist for a demonstration on your next visit. Antiseptic rinses help get rid of bacteria that cause gum disease and bad breath. Fluoride rinses help prevent tooth decay. Dentists recommend rinsing once or twice a day. You may find a powered toothbrush better, especially if you have hand, arm, or shoulder problems that make manual brushing difficult. If you have children, be sure to buy them child-sized brushes so they fit their hands and mouth, and are easier to use.