Question: What is the ruling on teeth whitening?
Answer: “There is no prohibition in [using] what does not have an opposition in it in terms of tooth reshaping or distorting the teeth. For the legislation of [using] the siwaak is for cleaning the teeth”*.
* I asked the Shaikh this question on 19 Jumada al-Awwal 1437 corresponding to Feb 29, 2016
Faisal Ibn Abdul Qaadir Ibn Hassan