Someone who gets tooth stains may want a whitening toothpaste .
一些人牙齿染色的人可能需要增白牙膏。
Whitening toothpastes will remove only surface stains , such as those caused by smoking , tea or coffee .
增白牙膏将可以去除牙齿表面色斑，比如由吸烟，喝茶或咖啡引起来的。
Some kind of whitening agent : sometimes these are variations on hydrogen peroxide , which are toxic when ingested .
一些增白剂：有时候增白剂是过氧化氢的变体，如果被吞食是有毒性的。
People have gone hog wild for whitening pastes , and there is concern about their longterm safety , by dentists in particular .
人们对增白牙膏趋之若鹜，关于它的长期安全性，常有担忧，尤其是牙医们。
Faced with a entire aisle full of toothpaste options-one whitening , one brightening , one with extra sensitivity , and one with extra fluoride and baking soda ingredients-their eyes glaze over and they stare , circuit-fried and numb , unable to choose or buy anything .
