Whitening toothpastes does contain chemicals or polishing agents that can help to remove surface stains from teeth. Therefore if your teeth are darker then they used to be due to surface stains, whitening toothpaste can help to brighten your teeth. On the other hand if your teeth are darker due to deeper stains, either because of injury, age or certain medications, whitening toothpastes will not give effective results. Unlike bleaching whitening toothpastes do not change the color of the teeth to a whiter shade. If you fall into this case scenario then talk to your dentist to find out your other teeth whitening options.