n.牙骨质
The root is covered with a hard material called cementum. 牙根上覆盖着的坚硬材料叫作牙骨质。
These findings may contribute to the development of a periodontal treatment that includes cementum regeneration. 这些结果可以有助于牙周治疗的发展，包括牙骨质的再生。
