pyorrhoea

例句：

1. 1. The dentist advisedhim to brush his teeth twice a dayto prevent pyorrhoea.
   牙医建议他每天刷牙两次以防止牙垢。
2. 2.The patient's mouth was filled withpyorrhoea, making it difficultfor her to eat.
   病人的嘴里满是牙垢，使她难以进食。
3. 3. The doctorprescribed a special toothpaste to helpremove the pyorrhoea from herteeth.
   医生开了一种特殊牙膏来帮助从她的牙齿上去除牙垢。