double helical tooth

例句：

1. 1. The dentist uses a double helical tooth to clean the patient's teeth.
   牙医使用双螺旋齿来清洁病人的牙齿。
2. 2. The scientist discovered a new double helical structure in the crystal.
   科学家在晶体中发现了一种新的双螺旋结构。
3. 3. The double helical tooth has been used in many applications, such as in the manufacturing of plastic products.
   双螺旋齿被广泛应用于许多领域，如塑料产品的制造。