The fact "an electric toothbrush vibrates to clean teeth better" is illustrated with the story:1. Normal toothbrushes require strong wrists.2. You have to scrub your teeth.3. But if you scrub your teeth too hard, you could damage them.4. Electric toothbrushes apply just the right amount of pressure to clean your teeth.5. That's why some people think electric toothbrushes clean teeth better than normal toothbrushes.