Physical stain

• 物理性污染

Physical stain的用法和样例：

例句

1. Enamel erosion is permanent tooth damage and is easily misdiagnosed with attrition due to physical effect and enamel decalcification due to bacterial nature.
   牙釉质的腐蚀是一种永久性破坏，也常常与物理性因子所造成的磨耗及细菌性所造成的牙釉质脱钙相类似而被误诊。