六龄牙是在第二乳磨牙后面直接萌出的第一颗恒磨牙。因为它在六岁左右萌出,所以称它为六龄牙。 正常情况下,六龄牙的牙冠最大,牙尖最多,咀嚼面积最大。咀嚼时,六龄牙所承担的咬合力也最大,是口内咀嚼功能最强的牙齿。此外,六龄牙位于牙弓中段,是比较恒定而不容易错位的牙齿,对于保持上、下牙弓间的正常咬合关系和维持面部1/3部分的高度起着重要的作用。因此,人们把六龄牙称为 Sixth teeth are the first molars directly after the second molars. Because it erupts around the age of six, it is called a six-year-old tooth. Under normal circumstances, six-year-old tooth crown the largest, most cusps, chewing the largest area. When chewing, six-year-old teeth also bear the largest bite force, is the strongest mouth chewing function of the teeth. In addition, the six-year-old teeth in the middle of the arch, is relatively constant and not easy to dislocation of the teeth, to maintain the normal occlusion between the upper and lower arch and maintain the height of the face 1/3 plays an important role. Therefore, people call their six-year-old teeth