I had laser whitening done. It was worth it (I got it cheap as it was in S Africa £150 including a mould to use with the gel myself afterwards). I wouldnt have paid UK prices. The dentist had a set of different coloured teeth which he matched up and then matched again at the end. Apparently, I went 7 shades whiter. The result depends on how white your teeth are in the first place. You can`t get lighter than your own tooth colour. I asked him how those newsreaders in the US get their teeth so white and he said they have veneers.