A large part of the white effect you see form zoom is the dehydration of the teeth which makes them look white a chalky. When the teeth rehydrate the color comes back, It is generally the protocol in the dental community to use the custom fit trays on your teeth for 1 hours a day for a period of days or months. That will get you your greatest result. If that doesn't achieve what you are looking for then you might look into veneeers.