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人一共有几个牙齿
更新时间: 2020-10-23 00:00:00  

人类的牙齿颗数在28-32之间。28颗牙齿是成年人最基本的配备,另外四颗则是偶有萌出的智齿。28颗牙齿是上下对称的,每半边上下两排各有2个切牙,1个尖牙,2个双尖牙和3个磨牙。

牙齿的主要构成物质为牙质,外面包有牙釉质和牙骨质。牙骨质外还有由纤维组成的牙周膜,把牙齿固定在牙槽中。牙的中央有牙髓腔,内充满牙髓,并有丰富的血管和神经。

关键词: 共有 牙齿

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