I had a cleaning but my teeth are not whiter.
 
What is going on?
 
A 'cleaning' removes the surface stains but will not whiten teeth as such. To whiten teeth you have to use a whitening agent of some type.
 
See the link on the left Whiter Teeth for more information.
                   Before cleaning the teeth
After cleaning the teeth. The yellow tartar and surface staining is what is removed in a cleaning. The teeth themselves are not 'whitened' by the cleaning process.