Toothbruhes come in all sizes and colors—some spin and others pulsate. But a toothbrush is worthless if you're brushing incorrectly. Our ShopSmart editors consulted with Kimberly Harms, DDS, a dentist in Farmington, Minn., and a consumer adviser for the American Dental Association, on keeping your teeth healthy and when an electric toothbrush comes in handy.

Who should buy a power toothbrush? All you really need is a good soft-bristled manual toothbrush if you take the time and effort to really clean your teeth. But if you have arthritis, lack dexterity, or would like some extra power, the powered toothbrushes are wonderful.

What’s the biggest brushing mistake people make? Just swishing the toothbrush around without making sure to reach all areas of the mouth. People tend to brush their teeth very quickly, and they end up missing spots, especially in the back of their mouth. And that’s a real problem because plaque is full of bacteria and it can lead to gum disease and cavities.