Hello there. I would like to whiten my teeth, which are quite discoloured. I do not smoke so I guess it’s age and tea drinking mainly! (I am 65yrs old). Most dentists use peroxide based systems,but some people say these damage the teeth enamel. Are these chemicals safe to use or will they possibly damage the enamel in the long term? There seem to be some articles that suggest peroxide should not be used. Thank you.