Wisdom teeth are the last (third) set of molars in adult dentition, usually growing in around 18 years of age. For evolution reason, these teeth are rarely fully grown. A half grown or crooked wisdom tooth does not have any function only to make it impossible to clean and to cause decay because of the uncleansibility. In addition these teeth can often cause problems to adjacent teeth and make dentition crowded. Therefore, the dentists will usually recommend having these crooked or impacted wisdom teeth taken out.