The last adult teeth to appear are the wisdom, teeth, four teeth at the corners of your mouth, which often appear around the age of 20. These teeth often come in badly aligned.
These can then crowd or damage adjacent teeth, even damage the jawbone or nerves. They may never actually appear above the gum line in which case they are called impacted. They may be more subject to decay and infection.
Wisdom teeth therefore often require extraction. Examination, including x-rays, will make it possible to determine the recommended course of action – best performed sooner rather than later. Extraction is easier when you are younger, and can prevent problems rather than waiting for them to occur.
The difficulty of removal depends on the exact situation with your wisdom teeth. An impacted wisdom tooth may have to be removed in small pieces.