tooth annulus

例句：

1. 1. The dentist performeda tooth extraction on the patient.
   牙医为患者进行了一次拔牙手术。
2. 2. Thetooth annulus is important for maintainingproper jaw alignment.
   牙髓韧带对于保持正确的颌骨对齐非常重要。
3. 3. The toothannulus can be damaged by traumaor infection.
   牙髓韧带可能因创伤或感染而受损。