I have had teeth whitening done in the past. It was a home whitening procedure that I purchased from the dentist. However, I was not satisfied with the result. Rather than making my teeth whiter it simply made then brighter (as in shiny). At most I would say they were 1 shade whiter (in fact I did not even have to change my crown as the result was not that great.) My teeth are not yellow but I would like a whiter smile.
I have seen pictures of people who have had whitening procedures and in-between top ups (the 2 year period) they seem to have really yellow teeth. I was wondering if I have another procedure done such as zoom/laser whitening would my teeth become more yellow than they are now in a few years time once the procedure has worn off? And once I have the procedure done would it mean that I would have to keep it up i.e. if I have it done once in the long run will it make my teeth look worse?

Many Thanks