This involves rebuilding the tooth crown using synthetic proteins, which are similar, but not quite identical, to human enamel.

这包括使用合成蛋白质重建牙冠，这种蛋白质与人类牙釉质相似，但并不完全相同。

It used to be that the common but complicated procedure to get a tooth crown required several visits to the dentist's office.

以往患者要去牙医诊所多次才能完成像安装牙冠这样普通但复杂的手术。