In our office teeth whitening is accomplished by making customized rubber molds from accurate impressions. These are worn at home using a whitening agent provided by us. The results can also be variable but this method is usually more effective than the over-the-counter products.
Some tooth pastes will whiten teeth, however they will only remove surface stains and tend to be abrasive.
There are over-the-counter teeth whitening products which are very variable in their effectiveness.