(Concern) I'm curious about teeth whitening.

My tooth color has been turning yellow for a long time.

I like coffee and drink it every day, so my teeth color has changed.

How nice it is to see clean white teeth when you smile.

I think teeth whitening would look neat and clean, so it would be good.

Is teeth whitening a one-time procedure, or do I need to do it multiple times?

I am curious about how much the cost will be.

I also want to know about precautions and side effects.