Each tooth whitener is different so you can get results that differ from medical information. This does not mean that you have performed the treatment wrong. Everybody has different teeth. There are different ways of bleaching. People use a tray that is formed to the shape of their teeth, then they put the recommended liquid into the tray and they also use whitening kits that may contain different choices of whiteners.
Different people resort to different types of whitening systems according to their expectations.
All teeth typically have three layers. The inner layer of the tooth is called dentin. The root is connected to the jawbone. They are all replaced by 32 permanent teeth, four central incisors, four lateral incisors, four cuspids , eight bicuspids and twelve molors. There are four wisdom teeth that grow in later.