An intervention could be, for example, to give some patients an electric toothbrush that helps them care for their mouths better, while other patients just get a regular toothbrush.

• 举例来说，干涉就是在一些病人用普通的牙刷时，给另一些病人一把电动牙刷，它能帮助他们更好地照顾他们的口腔。