You can refer to the reputation of a treasure, the praise list of a group, and a public question and answer. Generally, the after-sales evaluation of such platforms is more real. Want to whiten teeth, there are quick whitening and deep whitening. If your teeth are particularly dark, deep whitening is recommended. I did cold light whitening in Bailey's mouth last year, just on Huzhou Road, Gongshu District. Up to now, the color has not changed much and the side effects are not obvious.