If you have brown or gray teeth, then bleaching will not be as effective as you will expect. When shopping for this product, do keep in mind that the crowns, the fillings and the veneers will not be affected by the whitening action of the paste. Complement the use of the whitening toothpaste with the services of professional teeth cleaner. Even without specialty toothpastes, the sensitivity is usually over in two days. However, persons with recessed gums, faulty tooth restoration and cracked teeth are more likely to encounter shooting pains. Irritation Bleaching agents contain peroxides. Peroxides when it gets in contact with the soft tissues inside the mouth will often give a tingling sensation that may not be pleasant to about half of the patients undergoing teeth whitening. This is why local home teeth whitening products have become very popular. The dentist will always give the best advice, treatment and service, and it is recommended that even for simple cosmetic enhancements there must at least be a professional consultation. After the initial consultation, the process of getting an appointment, finding the time and actually sitting in the dentist's chair is not always convenient besides there are a lot of conditions where it is actually more practical to get a teeth whitening kit and apply it at home where the person could save enormously on fees and time. But for major teeth issues like wear and discoloration, then the porcelain veneers can be used as the answer. For extreme cases of discolored set of teeth, the porcelain veneer can be used as well. When used and fitted the way, these veneers can promise longevity and will surely enhance the smile and the whiteness of the teeth. This kind of customization ensures that the mouthpiece will be of perfect fit and that this maximizes the application of the gel that contains the peroxide. Contrast this with the commercially-produced mouthpiece trays which may be ill-fit for the person because the design of the trays is not intended for the person in the first place. Since over the counter teeth whitening trays are milder, it would take longer and more treatments but it would also prevent gum irritation and tooth sensitivity. Another popular concern is whether bleaches weaken the enamel of the tooth. A study conducted by Kugel et al confirms that indeed repetitive and prolonged use of peroxides could weaken the tooth's enamel.