I had a tooth whitening system from my dentist. He made impressions of my teeth, top and bottom. He made me dental trays. The system had cartridges of "stuff" I squeezed into the trays each night and slept with. The entire system cost $600.00. Over the coarse of six weeks my teeth looked good, however I developed a painful sensitivity in my teeth. It was worth it, I would do it again if I could.