This slightly rounds out the area you 're going to whiten . Go to Image > Adjustments > Hue / Saturation . For the teeth , choose Yellow in the edit screen and slide the Saturation bar down some . Then go to the edit screen again and choose Master and slide the Lightness bar up some .

Answer the following question: What may be the reason I am giving out detailed instructions ?
I am trying to help someone edit their photos so the subjects have a whiter smile .