The over-the-counter products are weaker. That means less active whitening but also less risk to the gums, should the whitening agent come in contact. "All of the products are safe if used as directed," Messina says. Still, they can increase sensitivity of teeth and they can irritate gum tissue. "Anything that doesn't feel right, you should see your dentist." “A broken system”: the contract and the crisis facing NHS dentistry
Intrinsic stains are those that form on the interior of teeth. Intrinsic stains result from trauma, aging, exposure to minerals (like tetracycline) during tooth formation and/or excessive ingestion of fluoride. In the past, it was thought that intrinsic stains were too resistant to be corrected by bleaching. Today, cosmetic dentistry experts believe that even deep-set intrinsic stains can be removed with supervised take-home teeth whitening that is maintained over a matter of months or even a year. If all else fails, there are alternative cosmetic solutions to treat intrinsic staining, such as dental veneers. Dental Implants London - WATCH WARNING