Hello If external stains then cleaning will help but if internal then you have to go for bleaching

Professional cleaning,bleaching (office/home),etc.

Hello, I have gone through your query, yellowish stain may be of two types either they are external or internal stains. For external stain , ultrasonic scaling For Internal stain, Bleaching Treatment may requires. Thank You

Any treatment done in a dentist's office will be safe. If the yellow stains are extrinsic they can be removed by teeth cleaning through a procedure called as scaling. This will not lighten the teeth but will bring out the natural shade of your own teeth. If you want to lighten up the natural shade you can go for professional session of teeth bleaching. Talk to your dentist for a case evaluation so that the best options applicable for your case can be explained to you. Regards.