the pain is minimal according to my experience. the problem with cleaning all in one session is, usually cleaning half takes 1 hour, so if you do both sides together, either you will open you mouth for 2 hours, which is uncomfortable for you; or the nurse will speed up and not doing a thorough job.
【在 h***s 的大作中提到】 : 谢谢回答. : 请问: : 是什么原因"normally" each time they do half