| 3. | The teeth located between the cuspids and the molars , having either two or three cusps . the bicuspids are numbered 4 , 5 , 12 , 13 , 20 , 21 , 28 & 29 . also known as premolars 位于尖牙和磨牙(臼齿)之间的牙,所有双尖牙都有两个或三个牙尖.双尖牙被编号为4 , 5 , 12 , 13 , 20 , 21 , 28和29 .也被称为前磨牙(臼齿) |