While you can find many over-the-counter whitening kits at your local drug store, professional whitening is a better alternative. Professional whitening services offer a longer lasting impact than over-the-counter whitening kits. Professional whitening works better because at home whitening kits use hydrogen peroxide to achieve the desired results, while professional whitening can utilize carbamide peroxide. The carbamide peroxide is comprised partially of hydrogen peroxide, but it is a more stable compound, yielding whiter teeth and less sensitivity. Professional whitening also allows the dentist to ensure that the chemicals are only coming into contact with your teeth rather than your gums or tongue.