Before we begin to figure out how to whiten teeth we must know how they become yellow in the first place.
There are many factors that could be the cause of yellow teeth from the food and drink an individual ingests to genetics and overall oral hygiene.
Each tooth is made up of four tissues – enamel, which is the white that covers and protects the tooth; dentin, this supports the enamel and will the hard yellow material responsible for carrying nerves; pulp is at the very centre of the tooth containing the blood and lymph vessels and the cementum, which is the tissue enveloping the root of the tooth.
The two tissues that play the biggest role in the colouring of the tooth are the enamel and the dentin. Certain food and drink will have an immediate reaction, staining the enamel however the larger problem is the foods that are breaking down the enamel, weakening it as we grow older. Because the enamel is breaking down, it begins to reveal the dentin underneath.