Compositions and methods for whitening the teeth of a patient or subject include the application of at least one tooth whitening composition having a viscosity of at least 100 centipoise to the surface of a stained tooth, accompanied by the application of a sealant composition that forms protective film or coating on the tooth surface to resist moisture contamination of the oxidizing composition. The whitening procedure can be further enhanced by removal of acquired pellicle from the tooth surface prior to application of oxidizing and sealant compositions. The novel procedure allows for a high degree of tooth whitening by protecting the oxidizing composition while it is in contact with the tooth surface.