人的一生有两副牙齿——乳牙和恒牙。乳牙到六岁左右开始动摇脱落,长出恒牙。最早萌出的恒牙,是在乳牙后面,左右上下新长出的四颗大磨牙。因为一般在六岁时萌生,所以称作“六龄牙”。这磨牙在整个牙列中地位重要,分布在颌骨上下左右四个中心地带,就象四个支柱,不仅在乳、恒牙交替时期担负着主要的咀嚼任务,即在整个恒牙中,也是咀嚼力量最强的牙齿。因为它最早萌生,以后乳磨牙脱换长出的恒牙和新长的恒牙,都要向它靠拢。它对颌骨的发育和正常咬合关系的建立.都有卜分重要的影响。可是有些家长对六龄牙的重要性不了解,不重视保护;有的误认为是乳牙,轻易拔去。由于六龄牙萌出早,咀嚼面积大,牙面上沟裂点隙多,因 Human life has two teeth - teeth and permanent teeth. Deciduous teeth began to shake the six-year-old off, grow permanent teeth. The earliest eruption of permanent teeth, behind the deciduous teeth, grow up and down about four new molars. Because usually germinated at the age of six, it is called “six-year-old teeth.” The molars are important in the entire dentition. They are distributed in the four centers of the mandible, like the four pillars. They not only perform the main tasks of chewing during the alternation of milk and permanent teeth, but also in the entire permanent tooth Chewing the strongest teeth. Because it is the earliest initiation, after the molar teeth out of new permanent teeth and permanent growth, we must move closer to it. It has important implications for the development of jaws and the establishment of normal occlusion. However, some parents do not understand the importance of six-year-old teeth, do not attach importance to protection; some mistaken for deciduous teeth, easily pulled. As the six-year-old teeth eruption early, chewing large area, the surface of the tooth groove crack more, due to