Q. Yesterday my 16 yr old son had his teeth whitened using the Zoom professional chairside whitening system., he had been in total agony every since, he is not given to complaining about pain. He knew to expect some discomfort., is this normal? he had the procedure repeated 3 times during the session, is this normal practice? He has since said, it was not worth the pain for the sake of white teeth following removal of his brace!