WISDOM TEETH
智齿
The largest teeth. Some people never develop them, others have up to four, one in each corner.
智齿是所有牙齿当中体积最佳的一种，有的人一辈子都不会长出智齿，而有的人则会在牙槽骨上最里面的上下左右各冒出一颗。
PROBLEMS: Sometimes wisdom teeth don’t erupt through the gums properly and a gum flap extends over the crown. Bacteria get stuck underneath this flap, making the area inflamed.
智齿常常不会“规矩”的顺着牙龈长出，而是在牙冠的一侧冒出一瓣牙龈。而“躲藏”在牙肉空隙之内细菌往往会造成这一区块出现红肿的现象。