periodontal lignment的用法和样例：
例句
- Effects of continuous and intermittent forces on the function of secreting osteoblast-like markers by human periodontal ligament cells in vitro.
比较间歇性和持续性牵张力对人牙周膜细胞成骨样细胞分泌活性的影响。 - After growing them, they found their structures had matured into the components that make teeth, including dentin, enamel, dental pulp, blood vessels, and periodontal ligaments.
经一段时间的生长，他们发现在结构上它们已形成包括牙本质，牙釉质，牙髓，血管，牙周膜的牙组织的各个组分。
