These growth factors cue stem cells to generate dentin, the bonelike substance that teeth are mostly made of.

这些生长因子会提示干细胞修复牙本质，这是牙齿成分中的绝大部分组成物质。

The root is covered by cementum, which is a bonelike substance that the periodontal ligament's fibers attach to.

包裹着牙根的是牙骨质，是一种骨样物质，也是牙周韧带纤维连接的部分。

The outer wall of the pulp, contains odontoblasts which are cells that secrete a bonelike substance called dentin, which is filled with protein and minerals.

牙髓外层有成牙质细胞，它们可以分泌一种叫牙本质的骨样组织，其中充满了蛋白质和矿物质。