Hello, I recently got a crown on a dental implant. It is quite pale color compared to my teeth around it. I decided to try and lighten my other teeth to match it. I tried Opalescence go 15% trays and did the whole box of 10 trays. Though they burned my gums and made white patches on them, and made a few temporary very pale white spots on my teeth, there was no color change at all to the main part of my teeth. I also used and went through a whole Colgate whitening pen, taking about a month, with no change whatsoever. I don't drink tea, coffee, red wine, or dark juice, and I don't smoke. I am wondering why the whitening isn't working, and wonder if I might have thin enamel and the yellow dentin showing through? When I was a kid I saw a dentist who polished my teeth with gritty paste every time, and one time a big chunk of my enamel broke off the next day. I also had braces, and after those I got a hole in my enamel which wasn't a cavity, which I had to get filled, and I am sure all the etching, and grinding off the glue, and buffing wasn't good for my enamel. My teeth do have a very shiny finish too, so I am kind of suspicious this could the cause of whitening products not working. Or maybe these products just aren't any good? I would be very grateful to anyone who can give me any advice, thank you!