Extracted wisdom tooth. Close-up of an upper wisdom tooth that has been extracted from a patient's jaw and gum. This view shows the build up of tartar formed from salts in the saliva around the gum line. At the top of the root at left is a granuloma (rounded area), a tissue mass formed by the immune system to contain an infection. Wisdom teeth are the third and last set of molars to emerge in the mouth. In many cases wisdom teeth are unable to emerge fully from the gum due to lack of available space. This may cause severe pain and usually results in their removal.