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肚子里的小牙牙萌芽 人的一生有两副牙,乳牙和恒牙。宝宝出生时口腔里虽没有牙,但是在他们的颌骨内却已藏着20枚乳牙牙孢,出生时已钙化。宝宝的乳牙由上下各4颗切牙(门牙)、2颗尖牙、4颗磨牙组成,共20颗。 当妈妈怀孕6周时,胎宝宝的口腔黏膜细胞在未来牙齿形成的地方迅速增生,形成上下两个弧形牙板。随后,口腔黏膜细胞继续增生,在上下弧形牙板形成10个球形隆起,这就是日后生长发育成的20个乳牙胚。
Small teeth in the stomach Buds have two teeth, teeth and permanent teeth. Although there are no teeth in the mouth when the baby was born, but in their jaws has hidden 20 teeth tooth deciduous, calcified at birth. The baby's deciduous teeth from top to bottom 4 incisors (incisors), 2 canines, 4 molars, a total of 20. When the mother is pregnant for 6 weeks, the baby's oral mucosal cells rapidly proliferate in the future where teeth form, forming two curved dental plates. Subsequently, the oral mucosal cells continue to hyperplasia, the formation of 10 spherical bulge in the upper and lower arc teeth, which is the growth of the future development of 20 primary tooth germs.