A、They always cause problems to teenagers. B、They appear when people get old. C、People who have wisdom teeth are wiser. D、Wisdom

Wisdom teeth are normally the last teeth to appear. This usually happens when people are in their late teen years or early 20s—in other words, when they are older and wiser. Wisdom teeth are at the back of the mouth(11)and they can grow into place normally and never cause a problem. But often there is not enough room for them in the mouth. They might crowd other teeth. Sometimes they even push sideways through the gums. An impacted wisdom tooth is one that fails to completely rise through the gums—the term is erupt.(12)Wisdom teeth that only partially erupt can leave space for bacteria to enter around the tooth. Infection is a risk in these cases. Wisdom teeth that become impacted are often removed. People should have the placement of their wisdom teeth examined between the ages of 16 and 20. X-rays can show wisdom teeth that are below the gums. The American Dental Association says removal is generally advised when wisdom teeth only partly break through the gums. Removal is also advised if there is a chance that the wisdom teeth will damage other teeth.(13)And removal is called for in cases where fluid collects around a wisdom tooth that is partly or fully below the gum.
11. What do we know about wisdom teeth?
12. Why can partially erupted wisdom teeth cause infection?
13. In what cases should we remove the wisdom teeth?