Most people start off adulthood with 32 teeth, not including the wisdom teeth. There are four types of teeth, and each plays an important role in how you eat, drink, and speak. Read on to learn more ...

The enamel on our teeth is the hardest tissue on the human body. A new study looks at the nanoscale structure of enamel from teeth dating as far back as 18 million years ago to see how it's changed.