However, no two sets of teeth are alike and may therefore react differently to different methods. No matter, it will always be safest to consult with a dentist before any teeth whitening are applied. This may cause a little inconvenience for a time but then it is always best and for the most part it is only a one time visit. 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. While brushing rids most of the materials that are accumulating, not all of it is removed. A bleaching agent will be placed and sealed inside the tooth that will make its shade lighter given time. Not all teeth are white. The teeth have sixteen varying shades. While a temporary tooth may be sparkling white, the teeth replacing it may be not. As a person grows older, the teeth darken in shade, no matter how healthy and no matter how clean. Unlike tooth whitening done at home, in-office whitening is conducted and monitored by a professional practitioner. Risks therefore, no matter how low and the aftereffects no matter how mild is attended too eliminating discomfort. Not everyone is a good candidate for in-office teeth whitening. People with tooth and gums hypersensitivity may undergo a different regimen or may be given home treatment kits for the patient to use though due to the patients hypersensitivity, the treatments and dosages are mild and will therefore take a longer period of time. The youthful glow and sparkle of young teeth will in time lost its sheen as the enamel starts developing tiny cracks that will eventually lose the crystalline rods in the tooth, thinning the enamel making the teeth more transparent and showing through the yellowish color of the dentin. Even discounting this natural aging of the teeth, eating habits, food choices, medication, lifestyles, health conditions and many other factors will develop the tiny cracks in the enamel allowing debris to accumulate between the spaces staining the teeth. Teeth whitening strips are a comparatively new addition to teeth whitening for home use. The idea is to provide the customer with less messy, more convenient, least expensive but still provide effective whitening results compared to other teeth whitening home systems. Teeth whitening strips are very flexible, very easy to use thin strips of plastic coated with bleaching agents that stick to the teeth.