Expectations: Significant whitening can be achieved in many cases, but there is no absolute way to predict how light your teeth will get. Please understand that teeth with multiple colorations, bands, splotches or spots due to, tetracycline staining or fluorosis do not whiten as well and may appear more spotted after treatment. These effects are generally short in duration. chair-side professional tooth whitening is not recommended for pregnant or lactating women, children under 14 years of age or any persons having known peroxides allergies.