Is it safe? Yes, absolutely. 10% CP whitening gel (used in our practice) was originally used to promote wound healing and gum health. Our bodies are equipped to handle peroxide and indeed, the human body actually makes peroxide in the liver, brain and eyes.
Does a light make any difference? All research shows that the light does not change the outcome of whitening.
Is there an advantage to in surgery whitening? Well no, the outcome of in-surgery whitening is not better than home tray whitening regardless of the number of applications.
In summary bleaching teeth has one of the major advances in cosmetic dentistry in the last 25 years. Tray based whitening with 10% CP is versatile, cost-effective and safe!