I'm curious about maintaining teeth whitening.

I love coffee too much.

Since middle school, I have been having one coffee a day... (When I was young, I didn't have money, so I survived on convenience store coffeeㅠ)

As a result, my teeth turned yellowㅠㅠㅠㅠ sob sob

My past self... I hate you ㅠㅠㅠ

Does teeth whitening last well?

Is there no way to whiten without receiving whitening treatment?