very effective for teeth that have been stained by smoking or by consuming substances, also by certai, such as teracycline, or speckled by fluoride as well as hereditary yellow teeth, making you enjoy a white and shiny smile for more than 2 to 5 years. Our professional teeth bleaching system is between 5 to 14 levels of shade improvement on the VITA shade guide, with an average improvement of 8 shades. the main ingredient is peroxide, which does no harm to the tooth structure. just 30 minutes-for your brightest, healthiest looking smile.