From whitening toothpaste to professional teeth whitening, there are many ways to change the colour of your smile. However, many people don't realise that not all dentist-provided whitening treatments are the same. Here are some options that your dentist might offer you if you ask them to whiten your teeth. In-Office Whitening In-office teeth whitening gives the fastest and most dramatic results of any kind of whitening treatment. While you lie back in the dentist's chair, the dentist applies a potent bleaching gel to your teeth.