Hydrogen peroxides are very potent bleaching agents that could cause tooth hypersensitivity and gum irritation. If you have this condition, it is best to use bleaching agents that contain carbamide peroxide. This agent may not be as fast acting but it is far gentler and would likely be recommended by your dentist. Nonetheless, all most all of us are born with bright shiny teeth. Even the permanent tooth that follows later invisibly white is cast. Through everyday wear and tear, the gaps between the rods fill up with debris, tannins and other coloration that stains it. Anything that is put in the mouth will leave its mark trough forming a pellicle film over the teeth which initiated in the pores between the rods. The teeth could be stained from the inside that will show on the outside that will not go away no matter the strips, gels, whitening pastes, bleaching pens and gurgles done. For example, blood that has leeched inside a tooth will discolor it. For these, internal bleaching must be done by a professional. Originally, these veneers are used on the surface of the tooth in order to correct uneven teeth. And these products as well are used to cover misalignment of the teeth. But more than that, oral practitioners have discovered other uses for these veneers. Right now, these are also considered as cosmetic veneers and they are used to deliver that bright and white smile. Those stains that form beneath the enamel are intrinsic stains. Previously, intrinsic stains are believed to be resistant to treatments although today most of it could be removed with close supervision from qualified professionals. Intrinsic stains are caused by the natural process of aging, trauma to the tooth, exposure to drugs containing tetracycline and flourosis. The dirt and the stains at the surface of the teeth will be removed, and will be primed up for the whitening session courtesy of the whitening toothpaste. Buy the desensitizing toothpaste. This is one good investment if you want to take teeth whitening seriously. This can be used before and after using the teeth whitening toothpaste.