When my five-year-old son suddenly exclaimed: ‘Why are your teeth so dirty, Mummy?’, I knew it was time to do something. Years of drinking coffee and red wine had left my teeth stained and grey. It had bothered me — I’d started wearing only dark tops (white made my teeth look lemon-yellow) and grimacing at friends through closed lips. But the ‘dirty teeth’ comment was the final straw. That day, I made an appointment at a smart dental practice to have my teeth professionally whitened.